A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
An order of parasitic, blood-sucking, wingless INSECTS with the common name of fleas.
A richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (Jablonski, Dictionary of Dentistry, 1992)
A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.
Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.
A family of immunoglobulin-related cell adhesion molecules that are involved in NERVOUS SYSTEM patterning.
The professional practice of primary eye and vision care that includes the measurement of visual refractive power and the correction of visual defects with lenses or glasses.
A vacuum tube equipped with an electron emitting CATHODE and a fluorescent screen which emits visible light when excited by the cathode ray. Cathode ray tubes are used as imaging devises for TELEVISIONS; COMPUTER TERMINALS; TEXT TELECOMMUNICATION DEVICES; oscilloscopes; and other DATA DISPLAY devices.
The prevention of access by infecting organisms to the locus of potential infection.
The fraudulent misrepresentation of the diagnosis and treatment of disease.
Facilities or services which are especially devoted to providing palliative and supportive care to the patient with a terminal illness and to the patient's family.
A former branch of knowledge embracing the study, description, and classification of natural objects (as animals, plants, and minerals) and thus including the modern sciences of zoology, botany, and mineralogy insofar as they existed at that time. In the 17th, 18th, and 19th centuries it was much used for the generalized pursuit of certain areas of science. (Webster, 3d ed; from Dr. James H. Cassedy, NLM History of Medicine Division)
A chronic, fungal, subcutaneous infection endemic in rural regions in South America and Central America. The causal organism is Lacazia labol.

Afferent sympathetic nerve fibres with aortic endings. (1/2264)

1. We recorded the electrical impulse activity of thirty-five single afferent fibres with aortic endings isolated from the third to the sixth left thoracic sympathetic rami communicantes of anaesthetized cats. The endings of each fibre were localized by mechanical probing of the opened aorta at the end of each experiment. 2. Twenty-four fibres had a single aortic receptive field. Eleven fibres had several and distinct receptive fields (from two to four): they were usually located in nearby aortic areas or, in addition, in other proximal portions of the arterial tree or in the adjacent pleura and connective tissue. 3. Twenty-nine fibres had conduction velocities ranging between 5 and 27 m/sec (Group Adelta), while six fibres had conduction velocities between 0-2 and 1-2m/sec (Group C). 4. The spontaneous impulse activity was in phase with the aortic pressure pulse and consisted of not more than one impulse per pressure pulse. It was increased during increases in aortic pressure and, conversely, decreased during decreases in aortic pressure. In vivo and post mortem studies showed that these mechanoreceptors had an impulse activity which rapidly adapted during sustained stimuli. They thus seem to signal pulsatile aortic stretch. 5. These aortic sympathetic afferents are likely to be part of a nervous pathway through which pressor reflexes, exhibiting positive feed-back characteristics, can elicited.  (+info)

Modality-specific hyper-responsivity of regenerated cat cutaneous nociceptors. (2/2264)

1. Experiments were performed on anaesthetized cats to investigate the receptive properties of regenerated cutaneous tibial nerve nociceptors, and to obtain evidence for coupling between them and other afferent fibres as being possible peripheral mechanisms involved in neuropathic pain. These properties were studied 6-7 months after nerve section and repair. 2. Recordings were made from 25 regenerated nociceptors; 14 were A fibres and the remainder were C fibres. Their receptive field sizes and conduction velocities were similar to controls. There was no significant difference between their mechanical thresholds and those of a control population of nociceptors. 3. Regenerated nociceptors were significantly more responsive to suprathreshold mechanical stimuli than were uninjured control fibres. This increase in mechanical sensitivity occurred in both A and C fibres, although A fibres showed a greater increase in mechano-sensitivity than C fibres. Over half of the regenerated nociceptors (13/25) showed after-discharge to mechanical stimuli which was never seen in controls; the mean firing rate during this period of after-discharge was significantly related to both stimulus intensity and stimulus area. 4. There was no significant difference between the heat encoding properties of regenerated nociceptors and control nociceptors. Cold sensitivity was similarly unchanged. Thus, abnormal peripheral sprouting was unlikely to account for the increased mechanical sensitivity of the regenerated fibres. None of the regenerated nociceptors were found to be coupled to other fibres. 5. These results suggest that the clinical observation of mechanical hyperalgesia in patients after nerve injury may have a peripheral basis. Based on this model, other signs of neuropathic pain (i.e. tactile or thermal allodynia) are more likely to be due to altered central processing.  (+info)

Sensory pathways in the spinal accessory nerve. (3/2264)

We obtained samples of spinal accessory nerve from patients undergoing radical surgery for tumours or nerve grafting in the neck. These were analysed by light and electron microscopy for the type of fibre. All contained fibres consistent with non-proprioceptive sensory function including pain.  (+info)

Biomechanics of stretch-induced beading. (4/2264)

To account for the beading of myelinated fibers, and axons of unmyelinated nerve fibers as well of neurites of cultured dorsal root ganglia caused by mild stretching, a model is presented. In this model, membrane tension and hydrostatic pressure are the basic factors responsible for axonal constriction, which causes the movement of axonal fluid from the constricted regions into the adjoining axon, there giving rise to the beading expansions. Beading ranges from a mild undulation, with the smallest degree of stretch, to more globular expansions and narrow intervening constrictions as stretch is increased: the degree of constriction is physically limited by the compaction of the cytoskeleton within the axons. The model is a general one, encompassing the possibility that the membrane skeleton, composed mainly of spectrin and actin associated with the inner face of the axolemma, could be involved in bringing about the constrictions and beading.  (+info)

Determinants of excitability at transition zones in Kv1.1-deficient myelinated nerves. (5/2264)

This study examines the role of K channel segregation and fiber geometry at transition zones of mammalian nerve terminals in the peripheral nervous system. Mutant mice that are deficient in Kv1.1, a fast Shaker K channel normally localized beneath the myelin sheath, display three types of cooling-induced abnormal hyperexcitability localized to regions before the transition zones of myelinated nerves. The first type is stimulus-evoked nerve backfiring that is absent at birth, peaks at postnatal day 17 (P17), and subsides in adults. The second type is spontaneous activity that has a more delayed onset, peaks at P30, and also disappears in older mice (>P60). TEA greatly amplifies this spontaneous activity with an effective dosage of approximately 0.7 mM, and can induce its reappearance in older mutant mice (>P100). These first two types of hyperexcitability occur only in homozygous mutants that are completely devoid of Kv1.1. The third type occurs in heterozygotes and represents a synergism between a TEA-sensitive channel and Kv1.1. Heterozygotes exposed to TEA display no overt phenotype until a single stimulation is given, which is then followed by an indefinite phase of repetitive discharge. Computer modeling suggests that the excitability of the transition zone near the nerve terminal has at least two major determinants: the preterminal internodal shortening and axonal slow K channels. We suggest that variations in fiber geometry create sites of inherent instability that is normally stabilized by a synergism between myelin-concealed Kv1.1 and a slow, TEA-sensitive K channel.  (+info)

Human axons contain at least five types of voltage-dependent potassium channel. (6/2264)

1. We investigated voltage-gated potassium channels in human peripheral myelinated axons; apart from the I, S and F channels already described in amphibian and rat axons, we identified at least two other channel types. 2. The I channel activated between -70 and -40 mV, and inactivated very slowly (time constant 13.1 s at -40 mV). It had two gating modes: the dominant ('noisy') mode had a conductance of 30 pS (inward current, symmetrical 155 mM K+) and a deactivation time constant (tau) of 25 ms (-80 mV); it accounted for most ( approximately 50-75 %) of the macroscopic K+ current in large patches. The secondary ('flickery') gating mode had a conductance of 22 pS, and showed bi-exponential deactivation (tau = 16 and 102 ms -80 11 mV); it contributed part of the slow macroscopic K+ current. 3. The I channel current was blocked by 1 microM alpha-dendrotoxin (DTX); we also observed two other DTX-sensitive K+ channel types (40 pS and 25 pS). The S and F channels were not blocked by 1 microM DTX. 4. The conductance of the S channel was 7-10 pS, and it activated at slightly more negative potentials than the I channel; its deactivation was slow (tau = 41.7 ms at -100 mV). It contributed a second component of the slow macroscopic K+ current. 5. The F channel had a conductance of 50 pS; it activated at potentials between -40 and +40 V, deactivated very rapidly (tau = 1.4 ms at -100 mV), and inactivated rapidly (tau = 62 ms at +80 mV). It accounted for the fast-deactivating macroscopic K+ current and partly for fast K+ current inactivation. 6. We conclude that human and rat axonal K+ channels are closely similar, but that the correspondence between K+ channel types and the macroscopic currents usually attributed to them is only partial. At least five channel types exist, and their characteristics overlap to a considerable extent.  (+info)

Distal axonopathy in peripheral nerves of PMP22-mutant mice. (7/2264)

A partial duplication of chromosome 17 is associated with Charcot-Marie-Tooth disease type 1A (CMT1A), a demyelinating peripheral neuropathy that causes progressive distal muscle atrophy and sensory impairment. Trisomic expression of peripheral myelin protein 22 (PMP22) whose gene is contained within the duplicated region is considered to be responsible for the disease. By using recombinant gene technology in rodents, we had demonstrated previously that PMP22 is sensitive to gene dosage. Homozygous PMP22 knockout (PMP22(0/0)) mice and transgenic animals carrying additional copies of the PMP22 gene develop distinct peripheral polyneuropathies. We have now performed a detailed morphometrical analysis of the L3 roots, quadriceps and saphenous nerves of these PMP22-mutant mice to study whether the myelin and potential axonal deficits are evenly distributed. The L3 roots and the peripheral nerves were chosen as representatives of the proximal and distal segments of the peripheral nervous system. When the roots were compared with the peripheral nerves, myelin deficiencies appeared more severe at the radicular levels, in particular the ventral roots. Decreased numbers of large calibre axons were a prominent feature in the motor branches of both strains of PMP22-mutant mice, and these axonal deficits were more severe distally. Active axonal damage was only observed in the nerves of PMP22(0/0) mice. Despite the distinct effects on myelination and the Schwann cell phenotype that characterize the neuropathies of PMP22-mutant mice, both strains develop a distally accentuated axonopathy as a common disease mechanism which is likely to be responsible for the neurological deficits.  (+info)

Fibre composition in the interosseous nerve of the pigeon. (8/2264)

The interosseous nerve of birds innervates a string of Herbst corpuscles located near the interosseous membrane between the tibia and fibula. Fibre composition of this nerve was assessed including both myelinated and unmyelinated axons. The diameter of the whole nerve is approximately 100 microm. Complete data were obtained for 3 nerves. The mean total number of myelinated fibres and unmyelinated axons was 2872 +/- 53. The mean number of myelinated fibres was 280 +/- 20 and that for unmyelinated axons was 2600 +/- 47. There was a broad distribution of diameters for myelinated fibres ranging from approximately 2 microm to 10 microm with a distinct peak at approximately 3-5 microm and a less prominent second peak at 6-8 microm. Similarly, myelin sheath thickness distribution showed 2 peaks, one at 0.6-0.8 microm and another at 1.4-1.6 microm. It is suggested that the group represented by the second peak innervates the Herbst corpuscles. The group of smaller myelinated fibres and the unmyelinated axons are assumed to innervate other types of receptors, some of which may be nociceptors.  (+info)

MalaCards based summary : Neuropathy, Hereditary Motor and Sensory, with Deafness, Mental Retardation, and Absent Sensory Large Myelinated Fibers, also known as hereditary motor and sensory neuropathy with hearing loss, intellectual disability and absent sensory large myelinated fibers, is related to charcot-marie-tooth disease and deafness and branchiootic syndrome 1. An important gene associated with Neuropathy, Hereditary Motor and Sensory, with Deafness, Mental Retardation, and Absent Sensory Large Myelinated Fibers is GJB1 (Gap Junction Protein Beta 1). Related phenotypes are intellectual disability, mild and decreased nerve conduction velocity ...
TY - JOUR. T1 - White Matter Hyperintensity Volume and Cerebral Perfusion in Older Individuals with Hypertension Using Arterial Spin-Labeling. AU - van Dalen, J. W.. AU - Mutsaerts, H. J. M. M.. AU - Nederveen, A. J.. AU - Vrenken, H.. AU - Steenwijk, M. D.. AU - Caan, M. W. A.. AU - Majoie, C. B. L. M.. AU - van Gool, W. A.. AU - Richard, E.. PY - 2016/10. Y1 - 2016/10. U2 - 10.3174/ajnr.A4828. DO - 10.3174/ajnr.A4828. M3 - Article. C2 - 27282862. VL - 37. SP - 1824. EP - 1830. JO - American Journal of Neuroradiology. JF - American Journal of Neuroradiology. SN - 0195-6108. IS - 10. ER - ...
Dive into the research topics of Association of white matter hyperintensity volume with decreased cognitive functioning: The Framingham Heart Study. Together they form a unique fingerprint. ...
Decreased glomerular filtration rate (GFR) and albuminuria may be accompanied by brain pathology. Here we investigated whether changes in these kidney measures are linked to development of new MRI-detected infarcts and microbleeds, and progression of white matter hyperintensity volume. The study included 2671 participants from the population-based AGES-Reykjavik Study (mean age 75, 58.7% women). GFR was estimated from serum creatinine, and albuminuria was assessed by urinary albumin-to-creatinine ratio. Brain MRI was acquired at baseline (2002-2006) and 5 years later (2007-2011). New MRI-detected infarcts and microbleeds were counted on the follow-up scans. White matter hyperintensity progression was estimated as percent change in white matter hyperintensity volumes between the two exams. Participants with a large eGFR decline (over 3 ml/min/1.73m2 per year) had more incident subcortical infarcts (odds ratio 1.53; 95% confidence interval 1.05, 2.22), and more marked progression of white matter ...
The article below may contain offensive and/or incorrect content.. Objective: Mean speed of responding is the most commonly used measure in the assessment of reaction time (RT). An alternative measure is intraindividual variability (IIV): the inconsistency of responding across multiple trials of a test. IIV has been suggested as an important indicator of central nervous system functioning, and as such, there has been increasing interest in the associations between IIV and brain imaging metrics. Results however, have been inconsistent. The present seeks to provide a comprehensive evaluation of the associations between a variety of measures of brain white matter integrity and individual differences in choice RT (CRT) IIV. Method: MRI brain scans of members of the Lothian Birth Cohort 1936 were assessed to obtain measures of the volume and severity of white matter hyperintensities, and the integrity of brain white matter tracts. CRT was assessed with a 4 CRT task on a separate occasion. Data were ...
TY - JOUR. T1 - Cerebral tract integrity relates to white matter hyperintensities, cortex volume, and cognition. AU - Seiler, Stephan. AU - Fletcher, Evan. AU - Hassan-Ali, Kinsy. AU - Weinstein, Michelle. AU - Beiser, Alexa. AU - Himali, Jayandra J.. AU - Satizabal, Claudia L.. AU - Seshadri, Sudha. AU - DeCarli, Charles. AU - Maillard, Pauline. PY - 2018/12/1. Y1 - 2018/12/1. N2 - We examined the relationship among white matter (WM) tract integrity, WM hyperintensities (WMH), lobar gray matter (GM) volumes, and cognition in the cross-sectional Framingham Offspring Study. Six hundred eighty participants (71.7 ± 7.7 years) completed cognitive testing and magnetic resonance imaging. Diffusion tensor imaging probabilistic tractography was used to reconstruct major WM tracts. We computed tract-specific mean fractional anisotropy (FA) and tract-specific WMH ratio. Linear regressions identified relations between tracts and lobar GM volumes. Partial least squares regression examined associations ...
The Framingham Offspring Cohort were recruited in 1971 and consisted of 5124 children and spouses of children of the original Framingham Cohort.28 Offspring subjects have been examined 7 times since 1971, and between 1999 and 2001, they were invited to undergo a brain MRI using a standard protocol. For the current analysis, only subjects attending examination 5 were included, and risk factor data from this examination were related to findings from brain MRI examinations. Data from examination 5 were used because a larger number of subjects had risk factor and MRI data available than from exam 6 or 7. Subjects were excluded from MRI examination if they had metal in the eyes or central nervous system, claustrophobia, valvular prosthesis, cardiac pacemaker, vascular clip, cochlear implant or other implantable device, or if they refused.. Of those offspring who attended examination 5, 3562 were alive as of September 2001, the cutoff for the analysis. Of them, 1939 had an MRI examination of the brain ...
Using advanced diffusion MRI, we aimed to assess the microstructural properties of normal-appearing white matter (NAWM) preceding conversion to white matter hyperintensities (WMHs) using 3-tissue diffusion signal compositions in ischemic stroke. Data were obtained from the Cognition and Neocortical Volume After Stroke (CANVAS) study. Diffusion-weighted MR and high-resolution structural brain images were acquired 3- (baseline) and 12-months (follow-up) post-stroke. WMHs were automatically segmented and longitudinal assessment at 12-months was used to retrospectively delineate NAWM voxels at baseline converting to WMHs. NAWM voxels converting to WMHs were further dichotomized into either: “growing” WMHs if NAWM adhered to existing WMH voxels, or “isolated de-novo WMHs if NAWM was unconnected to WMH voxels identified at baseline. Microstructural properties were assessed using 3-tissue diffusion signal compositions consisting of white matter-like (WM-like: TW), gray matter-like (GM-like:
Published in The Journal of Pediatrics, 2014. Recommended citation: Rollins, Caitlin K and Watson, Christopher G and Asaro, Lisa A and Wypij, David and Vajapeyam, Sridhar and Bellinger, David C and DeMaso, David R and Robertson, Richard L and Newburger, Jane W and Rivkin, Michael J (2014). White matter microstructure and cognition in adolescents with congenital heart disease. The Journal of Pediatrics. 165(5):936-944. https://doi.org/10.1016/j.jpeds.2014.07.028 ...
PURPOSE OF REVIEW: There has been a rapid increase in studies using diffusion-weighted magnetic resonance imaging (DWI) to interrogate white matter structure in the human brain. This review considers the evidence that interindividual variation in white matter structure is behaviourally relevant. RECENT FINDINGS: Maturation or deterioration of white matter throughout the lifespan relates to development or decline in specific cognitive skills. In addition, age-independent relationships between white matter anatomy and ability are found in healthy adult populations. Such relationships may in part be determined by genetics but can also be driven by experience. SUMMARY: Individual differences in white matter anatomy, visible using DWI, have consequences for behaviour. The discovery of such relationships highlights the potential for identification of imaging biomarkers that could predict how well patients will respond to specific interventions.
|jats:title|Abstract|/jats:title||jats:p|Microscopic features (i.e., microstructure) of axons affect neural circuit activity through characteristics such as conduction speed. Deeper understanding of structure-function relationships and translating this into human neuroscience has been limited by the paucity of studies relating axonal microstructure in white matter pathways to functional connectivity (synchrony) between macroscopic brain regions. Using magnetic resonance imaging data in 11354 subjects, we constructed multi-variate models that predict the functional connectivity of pairs of brain regions from the microstructural signature of white matter pathways that connect them. Microstructure-derived models provide predictions of functional connectivity that were significant in up to 86% of the brain region pairs considered. These relationships are specific to the relevant white matter pathway and have high reproducibility. The microstructure-function relationships are associated to genetic variants
S. Mori, S. Wakana, L.M. Nagae-Poetscher, and P.C.M. van Zijl. Amsterdam: Elsevier; 2005, 284 pages, $195.. Diffusion tensor imaging (DTI) is becoming increasingly available on clinical scanners, thus providing neuroradiologists and other investigators with the ability to assess and quantify white matter abnormalities in ways that were impossible with conventional MR imaging methods. DTI is an MR imaging technique that is sensitive to the diffusion of water in anisotropic tissue and is thus ideal for the imaging and characterization of white matter fiber bundles. Because of the complexity of white matter anatomy, the localization of tracts is difficult without a good understanding of their 3D relationships. This volume provides annotated 3D and cross-sectional maps derived from DTI data and is intended to enable the interpretation of the complex 3D white matter anatomy visualized with DTI and the identification of specific white matter tracts.. Chapter 1 includes a brief introduction to the ...
In this cohort of community-dwelling older adults, greater arterial stiffness was associated with greater volume of WMH localized within the left superior longitudinal fasciculus as measured 10 years later. Our results suggest selective spatial vulnerability of the white matter to long-term cerebrovascular consequences of central arterial stiffness in aging.. Our study extends previous cross-sectional findings in racially homogeneous cohorts of adults ranging in age from late 50s to mid-70s in 2 ways.13-17 First, we examined longitudinal associations in a racially diverse cohort of older adults living in the community, and second, we examined the spatial distribution of objective measures of white matter abnormalities, including hyperintensities and FA. Most neuroimaging studies have relied on semiquantitative ratings of hyperintensities combined across 2 large brain areas: periventricular and deep. Among the reports of a spatial distribution of brain abnormalities in relationship with arterial ...
NOS1-ex1f VNTR is associated with WM microstructure in females in a large sample of participants with ADHD and healthy controls. Whether this association is part of a neurodevelopmental pathway from NOS1 to ADHD symptoms should be further investigated in future studies.
Clinical Trials - clinicaltrials.gov Animal studies have shown that thyroid hormone can improve white matter integrity after damage to myelin, which insulates a...
Functional brain images are extraordinarily rich data sets that reveal distributed brain networks engaged in a wide variety of cognitive operations. It is a substantial challenge both to create models of cognition that mimic behavior and underlying cognitive processes and to choose a suitable analytic method to identify underlying brain networks.. Most of the contemporary techniques used in analyses of functional neuroimaging data are based on univariate approaches in which single image elements (i.e. voxels) are considered to be computationally independent measures. Beyond univariate methods (e.g. statistical parametric mapping), multivariate approaches, which identify a network across all regions of the brain rather than a tessellation of regions, are potentially well suited for analyses of brain imaging data. A multivariate method (e.g. partial least squares) is a computational strategy that determines time-varying distributed patterns of the brain (as a function of a cognitive task). ...
BACKGROUND Studies detailing the anatomy of the basal forebrain (BF) from a neurosurgical perspective are missing. OBJECTIVE To describe the anatomy of the BF and of the anterior perforated substance (APS), the BF emphasizing surgical useful anatomical relationship between surface landmarks and deep structures. METHODS White matter fiber microdissection was performed on 5 brain specimens to analyze the topographic anatomy of the APS and expose layer-by-layer fiber tracts and nuclei of the BF. RESULTS The APS, as identified anatomically, surgically, and neuroradiologically, has clear borders measured 23.3 ± 3.4 mm (19-27) in the mediolateral and 12.5 ± 1.2 mm (11-14) in the anteroposterior directions. A detailed stratigraphy of the BF was performed from the APS up to basal ganglia and thalamus allowing identification and dissection of the main components of the BF (septum, nucleus accumbens, amygdala, innominate substance) and its white matter tracts (band of Broca, extracapsular thalamic ...
Read about a study suggesting that analysis of white matter hyperintensity (a measure of the risk of stroke) may serve as a biomarker for SCD children.
TY - JOUR. T1 - A cyclooxygenase-2 inhibitor attenuates white matter damage in chronic cerebral ischemia. AU - Wakita, Hideaki. AU - Tomimoto, Hidekazu. AU - Akiguchi, Ichiro. AU - Lin, Jin Xi. AU - Miyamoto, Katsuichi. AU - Oka, Nobuyuki. PY - 1999/5/14. Y1 - 1999/5/14. N2 - The effects of nimesulide, a cyclooxygenase-2 inhibitor, were examined during chronic cerebral hypoperfusion. After bilateral ligation of the common carotid arteries in 30 rats, 21 received dosages of 2 or 5mg/kg nimesulide daily and nine received vehicle daily for 14 days. The serum was then analyzed biochemically, and pathological changes were estimated in the white matter by the emergence of major histocompatibility complex (MHC) antigen- immunoreactive activated microglia and white matter lesions. In the vehicle- treated animals, activated microglia and white matter lesions were observed. Following treatment with either 2 or 5mg/kg nimesulide, the magnitude of these changes was reduced (p , 0.001) without significant ...
Recent advances in magnetic resonance research have opened up new opportunities for gathering functional information about the brain. The development of diffusion imaging and diffusion tensor imaging (DTI) has offered the possibility to go beyond anatomical imaging and study tissue structure at a microscopic level in vivo. Currently, DTI provides an invaluable tool for the study and diagnosis of white-matter diseases. Increasing research focus has been placed on studying neuronal connectivity. An important application of DTI is fiber tracking, which allows elucidation of white-matter tracts. Combined with fMRI, information about white-matter tracts reveals important information about neurocognitive networks, and may improve our understanding of brain function. Recently, the potential of applying SENSE to DTI was demonstrated at 3.0 Tesla to improve acquisition speed and image quality. These studies have demonstrated the feasibility of fast fiber tracking in the human brain. Future research will ...
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Methods: Total daily activity (exercise and nonexercise physical activity) was measured for up to 11 days with actigraphy (Actical; Philips Respironics, Bend, OR) in 167 older adults without dementia participating in the Rush Memory and Aging Project. Eleven motor performances were summarized into a previously described global motor score. WMH volume was expressed as percent of intracranial volume. Linear regression models, adjusted for age, education, and sex, were performed with total WMH volume as the predictor and global motor score as the outcome. Terms for total daily physical activity and its interaction with WMH volume were then added to the model. ...
Transmission Electron Micrograph (TEM) of nerve; section of Schwann cell and myelinated axon. Myelin sheath in blue. Magnification: 45,000X; 9 x 7 print. - Stock Image C022/0085
In a major study that uses cutting-edge imaging, researchers show that people with depression have alterations in the white matter part of the brain.
Neurological function in patients with slowly growing brain tumors can be preserved even after extensive tumor resection. However, the global process of cortical reshaping and cerebral redistribution cannot be understood without taking into account the white matter tracts. The aim of this study was to predict the functional consequences of tumor-induced white matter damage by computer simulation. A computational model was proposed, incorporating two cortical patches and the white matter connections of the uncinate fasciculus. Tumor-induced structural changes were modeled such that different aspects of the connectivity were altered, mimicking the biological heterogeneity of gliomas. The network performance was quantified by comparing memory pattern recall and the plastic compensatory capacity of the network was analyzed. The model predicts an optimal level of synaptic conductance boost that compensates for tumor-induced connectivity loss. Tumor density appears to change the optimal plasticity ...
see equation (2.2)), that is elastin volume fraction VE, collagen volume fraction VC, radius rF of collagen fibres, density Λc of intermolecular cross-links, and the inverse of standard deviation measure μ−1F of collagen fibres orientation distribution. Mechanical problem M for obtaining arterial current (loaded) configuration (Pi: luminal pressure; ri (re): internal (external) radius; r: radial coordinate) from the (stress-free) reference configuration (α: opening angle; ri,o (re,o): internal (external) radius; ro: radial coordinate). Stages S0, S1, S2 and S3 of the addressed physiopathological mechanism. TGF-β, transforming growth factor beta; MMPs, matrix metalloproteinases; IL, interleukin; SMC, smooth muscle cell. For model details, readers can refer to §5. ...
Here is an interesting article in the LA Times that doesnt actually mention MS, let alone CCSVI, but it does mention cortisone, myelin, brain white matter, and oligodendrocytes: Basically the article seems to be saying (toward the end of the ...
The fundamental basis of axonal ensheathment in any species is to faithfully transmit neuronal signals along the nerve fibers and optimize desired cellular responses. To maximize the speed of conduction and/or to minimize the loss of nerve signals, many species evolved mechanisms in which axonal lengths remained short (as seen in insects) by increasing the diameter of the axons or by clustering voltage-gated Na+ channels to discrete unmyelinated regions of the axon, the node of Ranvier, as seen in myelinated nerve fibers of vertebrates. Most invertebrate species use some type of glial cells to ensheath their axons without generating a myelin sheath. The insulation is contiguous without any breaks, suggesting that primitive nodal structures or clustering of voltage-gated Na+ channels may not exist in invertebrates ...
able abnormalities abuse acquisition addition alcohol alterations analyses annual another assessed atlas axial barker bipolar brain cannon capsule cerebellar children clarify clinical clinically cluster clusters cognitive cohorts confirmed connections conservative consistent contradictory contrasts control controlled controls corr corrected correlated correlations covariates criteria deemed dept described developmental diagnosis diffuse diffusion disorder distortion drug duration eigenvector error evidence examine exclusion extensive extent findings functional gender gradient help hospital illness include included inclusion increasing independent inferior institute internal investigate kernel kingdom learning limb limbic linear longitudinal matrix meeting mixed model modulation month morbid motion much networks neurological patients periods population populations posterior potential prior processing prospectively psychiatric quality radiology rating reduction reductions registration related ...
Choline is an essential nutrient found in some foods and is taken as a supplement for memory, mood, muscle control and other brain and nervous system functions (1). Choline bitartrate is related to the B-vitamins and serves several vital biological functions throughout the body. One of its roles is to increase choline in the body. The body needs choline to synthesize phosphatidylcholine and sphingomyelin, two major phospholipids vital for cell membranes.. Phosphatidylcholine accounts for about 95 percent of total choline in tissues. Sphingomyelin is found in cell membranes and in the fatty sheath that wraps myelinated nerve fibers (2).. Choline is also needed to produce acetylcholine, a significant neurotransmitter involved in memory, mood, muscle control, circadian rhythm and other neuronal functions.. Choline also plays important roles in modulating gene expression, cell membrane signaling, lipid transport and metabolism, and early brain development (3).. According to the authors of the ...
I am trying to develop a simple axon model that represents nodes of Ranvier connected by perfectly insulating myelinated internodal segments. Sweeney channel mechanics are used at the nodes (sodium and leakage currents). I would like to apply stimulation to this model using the extracellular mechanism, with the extracellular potentials at the nodes of Ranvier calculated through interpolation within a FEM program (ANSYS Ansoft). Since the internodal myelinated segments are perfectly insulating, I did not add any channel mechanics or transmembrane capacitance to these segments, nor did I apply a non-zero extracellular voltage. My procedure code for creating such an axon is below ...
A team has found that external stimulation has an impact on the postnatal development of a specific region of the brain. The team is from the Childrens National Medical Center.
Health,...MIT team says cognition suffers as nervous system network decays with ...THURSDAY Jan. 15 (HealthDay News) -- The white matter that connects... By comparing brain scans of groups of healthy young and old adults M... White matter is made up of the neuronal axons that connect neurons in...,Memory,Loss,Tied,to,Brains,White,Matter,medicine,medical news today,latest medical news,medical newsletters,current medical news,latest medicine news
Colour enhanced Transmission Electron Micrograph (TEM) showing myelinated axon of a nerve cell in section. Magnification unknown. - Stock Image C017/5995
The traditional description of MS emphasizes the notion that this disease is an inflammatory and demyelinating condition of the white matter of the CNS. Consistent with this, a large number of MR imaging studies have been devoted to the detection, description, and quantification of white matter abnormalities of the brain and spinal cord of patients with MS (16). The increased use of MR imaging in the assessment of MS has, however, disclosed that the extent of white matter abnormalities measured using conventional MR imaging contributes only partially to the clinical manifestations of the disease, including the accumulation of irreversible disability. One of the main reasons for this discrepancy is likely to be the inability of conventional MR imaging to detect subtle structural changes (including axonal loss) known to occur in the so-called normal appearing tissue of the brain of patients with MS (1-4, 17, 18). In this context, several studies have shown that quantitative MR imaging technology ...
This unique volume is a comprehensive, well-illustrated study of the organization of the white matter pathways of the brain. Schmahmann and Pandya have analyzed and synthesized the corticocortical and corticosubcortical connections of the major areas of the cerebral cortex of the rhesus monkey. The result is a detailed understanding of the constituents of the cerebral white matter and the organization of the fiber tracts.
UCL Discovery is UCLs open access repository, showcasing and providing access to UCL research outputs from all UCL disciplines.
Panizzon MS, Fennema-Notestine C, Kubarych TS, Chen CH, Eyler LT, Fischl B, Franz CE, Grant MD, Hamza S, Jak A, Jernigan TL, Lyons MJ, Neale MC, Prom-Wormley EC, Seidman L, Tsuang MT, Wu H, Xian H, Dale AM, Kremen WS. Genetic and environmental influences of white and gray matter signal contrast: a new phenotype for imaging genetics? Neuroimage. 2012 Apr 15; 60(3):1686-95 ...
Nonspecific white matter changes is a condition in which white tissues in the brain change for some unknown reason. Though there...
White matter is brain tissue that is located below the surface gray matter. It is composed of nerve fibers that connect the different areas of the brain.
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Formisano, L., Lu, Y., Servetto, A., Hanker, A. B., Jansen, V. M., Bauer, J. A., Sudhan, D. R., Guerrero-Zotano, A. L., Croessmann, S., Guo, Y., Ericsson, P. G., Lee, K. M., Nixon, M. J., Schwarz, L. J., Sanders, M. E., Dugger, T. C., Cruz, M. R., Behdad, A., Cristofanilli, M., Bardia, A. 及其他11, OShaughnessy, J., Nagy, R. J., Lanman, R. B., Solovieff, N., He, W., Miller, M., Su, F., Shyr, Y., Mayer, I. A., Balko, J. M. & Arteaga, C. L., 2019 十二月 1, 於: Nature communications. 10, 1, 1373.. 研究成果: Article › 同行評審 ...
ObjectiveTo examine the association between a Mediterranean-style diet (MeDi) and brain magnetic resonance imaging white matter hyperintensity volume (WMHV).Des
Charcot-Marie-Tooth Disease with Deafness - Mental Retardation - Absence of Large Myelinated Fibers (Hereditary Motor and Sensory Neuropathy with Deafness - Mental Retardation - Absence of Large Myelinated Fibers): Read more about Symptoms, Diagnosis, Treatment, Complications, Causes and Prognosis.
TY - JOUR. T1 - Peripheral nerve injury triggers central sprouting of myelinated afferents. AU - Woolf, Clifford J.. AU - Shortland, Peter. AU - Coggeshall, Richard E.. PY - 1992/1/2. Y1 - 1992/1/2. N2 - THE central terminals of primary afferent neurons are topographically highly ordered in the spinal cord1. Peripheral receptor sensitivity is reflected by dorsal horn laminar location: low-threshold mechanoreceptors terminate in laminae III and IV (refs 2, 3) and high-threshold nociceptors in laminae I, II and V (refs 4, 5). Unmyelinated C fibres, most of which are nociceptors6, terminate predominantly in lamina II (refs 5, 7). There is therefore an anatomical framework for the transfer of specific inputs to localized subsets of dorsal horn neurons. This specificity must contribute to the relationship between a low-intensity stimulus and an innocuous sensation and a noxious stimulus and pain. We now show that after peripheral nerve injury the central terminals of axotomized myelinated afferents, ...
Background and purpose: White matter hyperintensities are characteristic of old age and identifiable on FLAIR and T2-weighted MR imaging. They are typically separated into periventricular or deep categories. It is unclear whether the innermost segment of periventricular white matter hyperintensities is truly abnormal or is imaging artifacts. Materials and methods: We used FLAIR MR imaging from 665 community-dwelling subjects 72-73 years of age without dementia. Periventricular white matter hyperintensities were visually allocated into 4 categories: 1) thin white line; 2) thick rim; 3) penetrating toward or confluent with deep white matter hyperintensities; and 4) diffuse ill-defined, labeled as subtle extended periventricular white matter hyperintensities. We measured the maximum intensity and width of the periventricular white matter hyperintensities, mapped all white matter hyperintensities in 3D, and investigated associations between each category and hypertension, stroke, diabetes, ...
View Stock Photo of Human Skin Crosssection Showing The Epidermis Dermis Perichondrium Elastic Cartilage A Myelinated Nerve Fiber And A Muscular Artery. Find premium, high-resolution photos at Getty Images.
Background and Purpose: White matter hyperintensities (WMH) are commonly seen on structural MRI of older adults and are a manifestation of underlying and adjacent tissue damage. WMH may contribute to cortical disconnection and cognitive dysfunction, but it is unclear how WMH affect intersecting or nearby white matter tract integrity. This study investigated the effects of WMH on tract microstructure by determining the spatial distribution of water diffusion characteristics in white matter tract areas adjacent to both intersecting and nearby WMH.Methods: We used diffusion and structural MRI data from 52 representative participants from the Lothian Birth Cohort 1936 (72.2 ± 0.7 years) including a range of WMH burden. We segmented WMH, reconstructed 18 main white mater tracts using automated quantitative tractography and identified intersections between tracts and WMH. We measured mean diffusivity (MD) and fractional anisotropy (FA) in tract tissue at 2 mm incremental distances from tract-intersecting and
Looking for online definition of dorsal longitudinal fasciculus in the Medical Dictionary? dorsal longitudinal fasciculus explanation free. What is dorsal longitudinal fasciculus? Meaning of dorsal longitudinal fasciculus medical term. What does dorsal longitudinal fasciculus mean?
The newly-diagnosed, neuroleptic-naive patients had lower FA scores in the brain compared with controls. There was positive correlation between FA scores and positive symptoms scores in frontotemporal tracts, including left fronto-occipital fasciculus and left inferior longitudinal fasciculus. This …
Myelinated fibers and axons distribution in phrenic nerve of male and female wistar- kyoto (WKY) and spontaneously hypertensive rats (SHR). Anaceres Ribeiro Rodrigues1, Renata da Silva Ferreira1, Helio Cesar Salgado2, Carlos Augusto Carvalho de Vasconcelos3, Valéria Paula Sassoli Fazan1* Abstract. Histological examination of the diaphragm showed gender differences in fiber composition but gender differences on phrenic nerve myelinated fiber morphometry were not thoroughly addressed. A descriptive morphologic and morphometric study of the phrenic nerves in male and female SHR and WKY was recently published but the myelinated fiber morphometry needs further exploration. After arterial pressure and heart rate recordings, phrenic nerves of young adult (20 week-old) male and female SHR and WKY were prepared for epoxy resin embedding and light microscopy. Morphometric analysis was performed with the aid of computer software, with special attention to myelinated fiber and their respective axons area ...
To better understand why this finding is important, you need to know the players. Subclinical cerebrovascular disease is defined as the presence of silent brain infarcts and white matter hyperintensities. Research has shown that individuals with greater white matter hyperintensity volume and evidence of subclinical infarcts are at greater risk of experiencing an ischemic stroke (especially cryptogenic stroke) or dying. (2). An ischemic stroke, also known as a cerebral infarction, is caused by a blockage in a blood vessel in the brain. Ischemic stroke is the most common type of stroke. Of the more than 795,000 people in the United States who have a stroke every year, about 87 percent of them are ischemic stroke.(3) Silent brain infarcts are strokes that are void of clinically overt stroke-like symptoms. However, they are associated with subtle cognitive and physical deficits that often are not noticed. According to a study reported in Stroke, about 20 percent of stroke-free older adults have ...
To assess whether there was a relationship between these functional interactions and white matter microstructure across participants, we used tract-based spatial statistics (TBSS) to investigate local correlations between FA and ppTMS/spTMS MEP ratio effect size (16). We used MEP ratios with 6- and 12-ms IPLs from right hand response trials in the pre-SMA/M1 IPL experiment and the rIFG/M1 IPL experiment. Therefore, we had four different and uncorrelated regressors in the TBSS multiple regression analysis. Effects were reported as being significant at a one-tailed statistical threshold of P , 0.001 (uncorrected) and a cluster size of ,10 voxels (16). We found 2 clusters significantly correlated with the TMS effect in the pre-SMA/M1 experiment at an IPL of 6 ms. These clusters lay in dorsal white matter likely to connect pre-SMA, premotor, motor, and parietal areas. At an IPL of 12 ms, we found 6 clusters significantly correlated with pre-SMA/M1 interactions. Again, some of these clusters lay in ...
There is a strong genetic risk for late-onset Alzheimers disease (AD), but so far few gene variants have been identified that reliably contribute to that risk. A newly confirmed genetic risk allele C of the clusterin (CLU) gene variant rs11136000 is carried by ∼88% of Caucasians. The C allele confers a 1.16 greater odds of developing late-onset AD than the T allele. AD patients have reductions in regional white matter integrity. We evaluated whether the CLU risk variant was similarly associated with lower white matter integrity in healthy young humans. Evidence of early brain differences would offer a target for intervention decades before symptom onset. We scanned 398 healthy young adults (mean age, 23.6 ± 2.2 years) with diffusion tensor imaging, a variation of magnetic resonance imaging sensitive to white matter integrity in the living brain. We assessed genetic associations using mixed-model regression at each point in the brain to map the profile of these associations with white matter ...
TY - JOUR. T1 - Relative conduction velocities of small myelinated and non-myelinated fibres in the central nervous system.. AU - Waxman, S. G.. AU - Bennett, Michael V. L.. PY - 1972/8/16. Y1 - 1972/8/16. UR - http://www.scopus.com/inward/record.url?scp=0015512637&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=0015512637&partnerID=8YFLogxK. M3 - Article. C2 - 4506206. AN - SCOPUS:0015512637. VL - 238. SP - 217. EP - 219. JO - Nature. JF - Nature. SN - 0028-0836. IS - 85. ER - ...
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
Regression of myelinated peripheral nerve fibers in the lower extremities contributes to sarcopenia and balance dysfunction in normal aging. This subclinical regression of myelinated fibers (MFs) is heavily influenced by alterations in microvasculature, though the mechanism underlying these age-related degenerative phenomena remains unclear. The aim of the present study was to examine age-related regressions in myelinated distal peripheral nerve fibers as well as capillary architecture in rats using both morphological and histochemical methods. MFs were categorized into tertiles of large, medium, and small sizes based on the distribution of MF diameters. A two-way ANOVA was used to assess effects of fiber size (large/medium/small) and group (young/elderly) on myelin thickness, axon diameter, myelin perimeter, axon perimeter, and G-ratio (axon diameter/fiber diameter). Significant main effects were observed for both MF size and group with respect to all dimensions except for G-ratio. Values for
Background: Schizophrenia can be conceptualized as a form of dysconnectivity between brain regions. To investigate the neurobiological foundation of dysconnectivity, one approach is to analyze white matter structures, such as the pathology of fiber tracks. S100B is considered a marker protein for glial cells, in particular oligodendrocytes and astroglia, that passes the blood brain barrier and is detectable in peripheral blood. Earlier Studies have consistently reported increased S100B levels in schizophrenia. In this study, we aim to investigate associations between S100B and structural white matter abnormalities.Methods: We analyzed data of 17 unmedicated schizophrenic patients (first and recurrent episode) and 22 controls. We used voxel based morphometry (VBM) to detect group differences of white matter structures as obtained from T1-weighted MR-images and considered S100B serum levels as a regressor in an age-corrected interaction analysis. Results: S100B was increased in both patient subgroups.
New findings by Columbia researchers suggest that for the development of Alzheimers disease, along with amyloid deposits, white matter hyperintensities (WMHs) may be a second necessary factor.
The clinical evidences of variable epileptic propagation in occipital lobe epilepsy (OLE) have been demonstrated by several studies. However the exact localization of the epileptic focus sometimes represents a problem because of the rapid propagation to frontal, parietal, or temporal regions. Each white matter pathway close to the supposed initial focus can lead the propagation towards a specific direction, explaining the variable semiology of these rare epilepsy syndromes. Some new insights in occipital white matter anatomy are herein described by means of white matter dissection and compared to the classical epileptic patterns, mostly based on the central position of the primary visual cortex. The dissections showed a complex white matter architecture composed by vertical and longitudinal bundles, which are closely interconnected and segregated and are able to support specific high order functions with parallel bidirectional propagation of the electric signal. The same sublobar lesions may ...
Also called brain rust, DeCarli says that when he began his research in 1990, everyone thought these hyperintensities were just innocent changes associated with aging.. He has since focused his attention on an emerging connection between white matter and neurological maladies and their less-mysterious counterparts in other parts of the body: stroke, heart attack, diabetes, hypertension and atherosclerosis.. Stroke and white matter hyperintensities, for instance, share the same risk factors, DeCarli says. Having these hyperintensities on your brain scan indicates that you are at risk for stroke.. Referring to it as the million-dollar question of my research, DeCarli has sought links between Alzheimers disease and white matter hyperintensities.. We found that hyperintensities injure the frontal lobes of the brain and impair the brains ability to manipulate and store information, he explains. DeCarlis research team also discovered that white matter hyperintensity-causing vascular ...
Critical white matter structures in the brains of babies who are born so prematurely that they weigh less than 1,500 grams develop more robustly when their mothers breast-feed them, compared with preemie peers who are fed formula.
The results remained the same regardless of a persons age, gender, ethnic group, education, and if they had a gene thought to be a strong risk factor for dementia, called the ApoEe4 gene.. The most interesting finding in this study was that white matter hyperintensities, or ministrokes, predicted memory problems, while strokes predicted non-memory problems, said study author Jose Luchsinger, MD, MPH, with Columbia University Medical Center in New York.. Traditionally, ministrokes and strokes are thought to have a common origin and to more strongly predict non-memory cognitive problems. There are an increasing number of studies challenging the idea that all white matter hyperintensities are similar to strokes. The fact that white matter hyperintensities more strongly predicted memory problems could challenge traditional views that white matter hyperintensities are milder versions of stroke that are produced only by conditions such as high blood pressure, said Luchsinger. Luchsinger says more ...
PubMedID: 26541556 | The cross-sectional and longitudinal relationships between white matter hyperintensities and dementia in patients with Parkinsons disease: A retrospective analysis of 132 patients in a single center. | Archives of gerontology and geriatrics | 11/28/2015
Following on from research showing that long-term meditation is associated with gray matter increases across the brain, an imaging study involving 27 long-term meditators (average age 52) and 27 controls (matched by age and sex) has revealed pronounced differences in white-matter connectivity between their brains.. The differences reflect white-matter tracts in the meditators brains being more numerous, more dense, more myelinated, or more coherent in orientation (unfortunately the technology does not yet allow us to disentangle these) - thus, better able to quickly relay electrical signals.. While the differences were evident among major pathways throughout the brain, the greatest differences were seen within the temporal part of the superior longitudinal fasciculus (bundles of neurons connecting the front and the back of the cerebrum) in the left hemisphere; the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord), and the ...
Following on from research showing that long-term meditation is associated with gray matter increases across the brain, an imaging study involving 27 long-term meditators (average age 52) and 27 controls (matched by age and sex) has revealed pronounced differences in white-matter connectivity between their brains.. The differences reflect white-matter tracts in the meditators brains being more numerous, more dense, more myelinated, or more coherent in orientation (unfortunately the technology does not yet allow us to disentangle these) - thus, better able to quickly relay electrical signals.. While the differences were evident among major pathways throughout the brain, the greatest differences were seen within the temporal part of the superior longitudinal fasciculus (bundles of neurons connecting the front and the back of the cerebrum) in the left hemisphere; the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord), and the ...
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Evidence-Based Complementary and Alternative Medicine (eCAM) is an international peer-reviewed, Open Access journal that seeks to understand the sources and to encourage rigorous research in this new, yet ancient world of complementary and alternative medicine.
Polydisperse fiber networks are the basis of many natural and manufactured structures, ranging from high-performance biobased materials to components of living cells and tissues. The formation and behavior of such networks are given by fiber properties such as length and stiffness as well as the number density and fiber-fiber interactions. Studies of fiber network behavior, such as connectivity or rigidity thresholds, typically assume monodisperse fiber lengths and isotropic fiber orientation distributions, specifically for nano scale fibers, where the methods providing time-resolved measurements are limited. Using birefringence measurements in a microfluidic flow-focusing channel combined with a flow stop procedure, we here propose a methodology allowing investigations of length-dependent rotational dynamics of nanoscale polydisperse fiber suspensions, including the effects of initial nonisotropic orientation distributions. Transition from rotational mobility to rigidity at entanglement ...
Honor Whiteman/ Medical News Today) - Scientists may have advanced our understanding of the brain mechanisms behind Alzheimers disease, after uncovering a process that precedes the buildup of toxic proteins that is a hallmark of the condition.. In a mouse study, scientists at the University of Southern California (USC) in Los Angeles reveal how damage to cells called pericytes can trigger white matter disease, which is associated with dementia.. Also, the study findings suggest that these brain changes may occur as early as the age of 40.. White matter disease is characterized by the degeneration of white matter. This is the brain tissue that contains nerve fibers, the thread-like structures that carry signals from the nerve cells, or neurons, to other areas of the body.. In white matter disease, these nerve fibers become damaged, and this causes problems with memory, thinking, and balance. (…). read full story ...
The present study suggests that localization of WMH within a specific neurotransmitter system may have a measurable negative impact on cognition in a selected population of AD patients with WMH. CHIPS score was associated with cognitive performance on the DRS, and accounted for 12% of the observed variance. Although the magnitude of this effect appears modest, it compares favorably with similar associations using general WMH.22 General WMH burden as measured by the ARWMC scale was correlated with CHIPS score, but was not significantly related to cognitive performance. This suggests that CHIPS is not simply a marker for greater WMH burden, but rather is reflecting a pathogenesis that may be more specific to cognition.. Previous work from our group has suggested that strategic WMH within cholinergic pathways is associated with executive and visual attentional dysfunction in a heterogeneous cohort of patients with cognitive impairment, both of vascular and degenerative etiologies.21 The present ...
A volume corrected Kratky model and the influence of the shape of the orientation distribution function on the molecular orientation in PPV and its precursor ...
DTI looks at the ability of polar molecules, such as water, to move in their local environment. For example, water molecules in the ventricles should be free to move in any direction; this roughly spherical movement is termed isotropic movement. At the opposite extreme, water molecules in the white matter tend to have their movement restricted by the membranes around them (axon and myelin) so that they can move relatively freely in one direction but not in others, resulting in elliptical shaped movement, referred to as anisotropic movement. Think of yourself stuck in the center island of a busy road trying to cross the street: your movement across traffic in front of you and behind you is restricted but you could likely move up and down the street in the direction of traffic. By connecting the adjacent anisotropic voxels, pathways and tracts can be inferred and disruptions to them identified.3 When compared to more conventional forms of imaging (i.e., diffusion weighted, T2-weighted alone [such ...
In vivo experiments in which continuous superperfusion of peripheral nerve allows equilibration with drug and experiments in which a drug bolus is delivered by percutaneous injection, analogous to clinical peripheral nerve block, show unequivocally that small myelinated axons (Aγ motor and Aδ sensory fibers) are the most susceptible to impulse annihilation. Next in order of block are the large myelinated (Aα and Aβ) fibers, and the least susceptible are the small, nonmyelinated C fibers ...
In this thesis we develop algorithms for quantitative analysis of white matter fiber tracts from diffusion MRI. The presented methods enable us to look at the variation of a diffusion measure along a fiber tract in a single ...
Di Paola, M., Moscatelli, A., Bigler, E. D., Caltagirone, C., & Carlesimo, G. A. (2011). White matter changes in patients with hypoxic amnesia. Neurocase, 17(1), 46-56. doi:10.1080/13554794.2010. ...
In my opinion the recent research paper, Differences in White Matter Fiber Tract Development Present from 6 to 24 Months in Infants with Autism (Am J Psychiatry 2012 ; 169 :589-600), reports a very important finding and represents a huge amount of work, but the study is quite incomplete both in what was chosen to be measured and how the findings are interpreted by the investigators, Jason Wolff et al. Moreover, even though this study has been touted in the news as a way of detecting autism early, it really isn t ready for prime time as a clear indicator of the autism diagnosis. I think this finding is about things that occur downstream of other biological factors that are driving these changes. And because these changes are downstream, they are fuzzier in that they reflect a mixture of lots of other influences. This makes it hard for them to clearly demarcate risk from lack of risk. Measuring what s upstream might bring us closer to a clinically useful brain measure of autism risk in young ...
Conclusion: These findings highlight white matter differences associated with breastfeeding that differ by sex and are not accounted for by perinatal/sociodemographic factors. Our results in females align with previous research in infants/children showing that breastfeeding exclusivity/duration is associated with greater white matter connectivity. Our results in males do not align with previous research, but different developmental trajectories in males and females may explain these sex-specific findings. The nutritional content of breastmilk and/or caregiver-infant interactions during breastfeeding may influence white matter development and may suggest the need for sex-specific nutritional strategies for infants to optimize neurodevelopment ...
Chris started his post-doc in the lab in September of 2015. He is interested in diffusion, motor learning, segmentation, and classification - and is spending most of his time at the lab developing methods to parcellate white-matter tracts with targeted tractography. He is currently exploring how diffusion metrics and white-matter connectional anatomy can be used to quantify and define the lobules of the human cerebellum - with applications in neurological disease, assessing population variability, and heritability.. Chris received his PhD an MA in Psychology at Concordia University, Montreal, under the supervision of Dr. Virginia Penhune. His graduate investigated the behavioural, structural, and functional correlates of learning and expert performance in young adults. He recently completed a post-doctoral fellowship with Dr. Arno Villringer and Patrick Ragert in the Motor Plasticity lab at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig (MPI-CBS) where he continued ...
We use functional MRI to identify the brain regions of the motor network involved in different aspects of motor learning and action observation. We also use structural MRI to investigate structural changes induced by motor training on in gray matter volume and white matter microstructure. These figures illustrates some of our recent findings,which are detailed in the actual publication.. ...
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Abstract Objective To evaluate progressive white matter (WM) degeneration in amyotrophic lateral sclerosis (ALS). Methods Sixty-six patients with ALS and
Researchers have confirmed and expanded on changes in structural efficiency of white matter in the brain that can be related to positive behavioral changes in subjects practicing the technique for a month and a minimum of 11 hours total.
1 Answer - Posted in: head injury, headache, neck pain, brain, disease - Answer: Im sure that didnt help. There are many types of it. Once the type ...
Most brains exhibit a substantial distinction between grey matter and white matter. Gray matter consists of the cell bodies of the neurons, while white matter consists of the fibers (axons) that connect neurons. The axons are surrounded by a fatty insulating sheath called myelin, giving the white matter its distinctive color. The outer layer of the brain is gray matter called cerebral cortex. Deep in the brain, compartments of white matter (fasciculi, fiber tracts), gray matter (nuclei) and spaces filled with cerebrospinal fluid (ventricles) are found.. The brain innervates the head through cranial nerves, and it communicates with the spinal cord, which innervates the body through spinal nerves. Nervous fibers transmitting signal from the brain are called efferent fibers. The fibers transmitting signals to the brain are called afferent (or sensory) fibs. Nerves can be afferent, efferent or mixed (i.e., containing both types of fibers).. ...
A study by researchers at Childrens National Health System provided direct evidence that targeting specific receptors in white matter cells after brain injury promotes cellular and functional recovery.
Marner, L.; Nyengaard, J.R.; Tang, Y.; Pakkenberg, B. (2003). "Marked loss of myelinated nerve fibers in the human brain with ... Marner, L; Nyengaard, JR; Tang, Y; Pakkenberg, B. (2003). "Marked loss of myelinated nerve fibers in the human brain with age ... While individual muscle fibers have similar strength between male and female, males have more fibers as a result of their ... Other differences that have been established include greater length in males of myelinated axons in their white matter (176,000 ...
Marner, Lisbeth; Nyengaard, Jens R.; Tang, Yong; Pakkenberg, Bente (2003). "Marked loss of myelinated nerve fibers in the human ... The midsagittal & fiber numbers in the anterior commissure that connect the temporal poles and mass intermedia that connects ...
Marner L, Nyengaard JR, Tang Y, Pakkenberg B (July 2003). "Marked loss of myelinated nerve fibers in the human brain with age ... Men were found to have a total myelinated fiber length of 176 000 km at the age of 20, whereas in women the total length was ... Testosterone has been found to act as an antagonist of the TrkA and p75NTR, receptors for the neurotrophin nerve growth factor ... resistance exercise and fiber type". The Journal of Steroid Biochemistry and Molecular Biology. 110 (1-2): 130-37. doi:10.1016/ ...
ISBN 978-1-84310-426-1. Marner L, Nyengaard JR, Tang Y, Pakkenberg B (July 2003). "Marked loss of myelinated nerve fibers in ... Peters A (1 January 2007). "The Effects of Normal Aging on Nerve Fibers and Neuroglia in the Central Nervous System". In Riddle ... reduction each decade in the total length of the brain's myelinated axons. Age can result in visual impairment, whereby non- ...
Marner, Lisbeth; Nyengaard, Jens R.; Tang, Yong; Pakkenberg, Bente (2003). "Marked loss of myelinated nerve fibers in the human ... that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical ... At the age of 20, the total length of myelinated fibers in men is 176,000 km while that of a woman is 149,000 km. There is a ... The total number of long range fibers within a cerebral hemisphere is 2% of the total number of cortico-cortical fibers (across ...
Marner L, Nyengaard JR, Tang Y, Pakkenberg B (July 2003). "Marked loss of myelinated nerve fibers in the human brain with age ... Recent evidence suggests that aging is also related to the loss of myelinated nerve fiber length and the mass of white matter, ... of total nerve fiber length as they age. These changes that develop through the aging process affect the connectivity of the ... Brunner F, Schmid A, Sheikhzadeh A, Nordin M, Yoon J, Frankel V (July 2007). "Effects of aging on Type II muscle fibers: a ...
ISBN 978-0-674-05730-2. Marner L, Nyengaard JR, Tang Y, Pakkenberg B (July 2003). "Marked loss of myelinated nerve fibers in ...
Waxman, S.; Ritchie, J. (1985). "Organization of ion channels in the myelinated nerve fiber". Science. 228 (4707): 1502-1507. ... In 1954 he turned his attention to the properties of mammalian non-myelinated nerve fibres, and since then has made many ... Waxman, S. G.; Ritchie, J. M. (1993). "Molecular dissection of the myelinated axon". Annals of Neurology. 33 (2): 121-136. doi: ... binding of tetrodotoxin has provided new information about the density of sodium channels in various types of nerve." Ritchie ...
... serves a protective function for peripheral nerve fibers. Damaged nerve fibers may regenerate if the cell body is ... axons are myelinated by oligodendrocytes, thus lack neurilemma. The myelin Blay Ambrose sheaths of oligodendrocytes do not have ... It forms the outermost layer of the nerve fiber in the peripheral nervous system. The neurilemma is underlain by the myelin ...
"Direct determination of membrane resting potential and action potential in single myelinated nerve fibers". The Journal of ... "Electro-saltatory transmission of nerve impulse and effect of narcosis upon nerve fiber". Am. J. Physiol. 127: 211-27. doi: ... Huxley AF, Stämpfli R (May 1949). "Evidence for saltatory conduction in peripheral myelinated nerve fibres". The Journal of ... Hartline DK, Colman DR (January 2007). "Rapid conduction and the evolution of giant axons and myelinated fibers". Current ...
In peripheral nerves, a loss of large myelinated sensory fibers occurs. Structures in the brain are also affected by FRDA, ... The disease primarily affects the spinal cord and peripheral nerves. The spinal cord becomes thinner and nerve cells lose some ... "Man with rare nerve condition climbs Mount Kilimanjaro to raise money for charity". ITV. Archived from the original on 15 ... Degeneration of nerve tissue in the spinal cord causes the ataxia; particularly affected are the sensory neurons essential for ...
Diagnostic tests include electromyography (EMG) and nerve conduction studies (NCSs), which assess large myelinated nerve fibers ... These nerves are not under a person's conscious control and function automatically. Autonomic nerve fibers form large ... the type of nerve fiber predominantly affected (motor, sensory, autonomic), or the process affecting the nerves; e.g., ... and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the ...
Recent studies show that septate junctions are also identified in the myelinated nerve fibers of the vertebrates. The main ... "A Drosophila neurexin is required for septate junction and blood-nerve barrier formation and function". Cell. 87 (6): 1059-68. ...
These nerves enter the tooth through the apical foramen as myelinated nerve bundles. They branch to form the subodontoblastic ... Sensory nerve fibers that originate from inferior and superior alveolar nerves innervate the odontoblastic layer of the pulp ... There are two types of nerve fiber that mediate the sensation of pain: A-fibers conduct rapid and sharp pain sensations and ... The dental pulp nerve is innervated by one of the Trigeminal nerves, otherwise known as the fifth cranial nerve. The neurons ...
Therefore, in a myelinated nerve fiber, a large number of molecular bonds are ordered around a radial axis of symmetry. Such a ...
The gray rami communicantes contain postganglionic nerve fibers of the sympathetic nervous system and are composed of largely ... This is in contrast to the white rami communicantes, in which heavily myelinated neurons give the rami their white appearance. ... Once the preganglionic nerve has traversed a white ramus communicans, it can do one of three things. The preganglionic neuron ... Each spinal nerve receives a branch called a gray ramus communicans (plural rami communicantes) from the adjacent paravertebral ...
The fibers are largely myelinated and run close to the spinal central gray for the length of the cord. Shorter fibers are ... Ventral propriospinal tract is a collection of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect ... closer to, longer fibers further from the gray. Other prominent components of the anterior columns are the medial longitudinal ...
Its fibers are largely myelinated. It is a component of the white lateral columns. Most prominent in the cervical and lumbar ... Lateral propriospinal tract is a collection of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect ... Shorter fibers are closer to, longer fibers further from the gray The tract is one of three propriospinal tracts in which most ...
Bone tissue is innervated by both myelinated (A beta and A delta fiber) and unmyelinated (C fiber) sensory neurons. In ... Stimulation of specialized pain-sensitive nerve fibers (nociceptors) that innervate bone tissue leads to the sensation of bone ... initiated by the faster myelinated fibers, followed by a slower and longer-lasting dull pain initiated by unmyelinated fibers. ... McCredie J (2007). Nerves in bone: the silent partners. Skeletal Radiology. 36: 473-475. Mach, D. Rogers, S. Sabino, M. Luger, ...
Myelinated fibers are located adjacent to the spinal central gray. Shorter fibers are closer to, longer fibers further from the ... The dorsal propriospinal tract is a collection of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect ... Some fibers are unmyelinated and scattered through the posterior column. The tract is one of three propriospinal tracts in ...
Underneath the gray matter of the cortex lies white matter, made up largely of myelinated nerve fibers running to and from the ... The cerebellum receives nearly 200 million input fibers; in contrast, the optic nerve is composed of a mere one million fibers ... Mossy fibers enter the granular layer from their main point of origin, the pontine nuclei. These fibers form excitatory ... Then the fibers decussate and form the middle cerebellar peduncle, terminating in the cerebellar cortex as mossy fibers. This ...
Underneath the gray matter of the cortex lies white matter, made up largely of myelinated nerve fibers running to and from the ... The mossy fiber and climbing fiber inputs each carry fiber-specific information; the cerebellum also receives dopaminergic, ... originating from mossy fibers and climbing fibers, both eventually terminating in the deep cerebellar nuclei. Mossy fibers ... this zone is devoid of parallel fiber inputs. Climbing fibers fire at low rates, but a single climbing fiber action potential ...
However, the myelin layer does not ensure a perfect regeneration of the nerve fiber. Some regenerated nerve fibers do not find ... Myelinated fibers lack voltage-gated sodium channels along the myelinated internodes, exposing them only at the nodes of ... In unmyelinated fibers, electrical impulses (action potentials) travel as continuous waves, but, in myelinated fibers, they " ... Damage to the myelin sheath and nerve fiber is often associated with increased functional insufficiency. Unmyelinated fibers ...
This myelinated division can then enter the sympathetic chain. Here four options are available to the fibers: (1) they can run ... Preganglionic nerves from the spinal cord synapse at one of the chain ganglia, and the postganglionic fiber extends to an ... Afferent nerve cell bodies bring information from the body to the brain and spinal cord, while efferent nerve cell bodies bring ... The general rule of interaction of the nerve fibers in the sympathetic nervous system begins at the spinal cord. Here they ...
... expression of integrins and the rate of regeneration of myelinated nerve fibers. In addition, GHK also increased axon count and ... GHK promotes nerve regeneration. Axon regeneration was studied using collagen tubes with incorporated peptides. GHK increased ... The human peptide GHK (glycyl-l-histidyl-l-lysine) has been found to stimulate blood vessel and nerve growth, increase collagen ... "Initial upregulation of growth factors and inflammatory mediators during nerve regeneration in the presence of cell adhesive ...
... which are often bundled together in what are called nerve fiber tracts. A myelinated axon is wrapped in a fatty insulating ... There are also unmyelinated axons). Myelin is white, making parts of the brain filled exclusively with nerve fibers appear as ... Some types of worms, such as leeches, also have an enlarged ganglion at the back end of the nerve cord, known as a "tail brain ... The fundamental bilateral body form is a tube with a hollow gut cavity running from the mouth to the anus, and a nerve cord ...
Tasaki, I (1954). "Nerve impulses in individual auditory nerve fibers of guinea pig". Journal of Neurophysiology. 17 (2): 97- ... He also was the first to show that electrical impulses traveling along myelinated nerve cells actually "jump" between the ... Tasaki, I. The electro-saltatory transmission of the nerve impulse and the effect of narcosis upon the nerve fiber. Am J ... While in Japan, he studied vertebrate nerve fibers and discovered the insulating function of the myelin sheath, a material that ...
... group A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are ... or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in ... Along myelinated nerve fibers, gaps in the myelin sheath known as nodes of Ranvier occur at evenly spaced intervals. The ... Lower motor neurons have two kind of fibers: Different sensory receptors innervate different types of nerve fibers. ...
For those with visual field defects optical coherence tomography has been recommended for follow up of nerve fiber layer ... Other causes of disc elevation clinicians must exclude may be: hyaloid traction, epipapillary glial tissue, myelinated nerve ... The optic nerve head, or optic disc is the anterior end of the nerve that is in the eye and hence is visible with an ... ODD can compress and eventually compromise the vasculature and retinal nerve fibers. Rarely, choroidal neovascularization may ...
... occurs widely in the myelinated nerve fibers of vertebrates, but was later discovered in a pair of medial ... Xu K, Terakawa S (1993). "Saltatory conduction and a novel type of excitable fenestra in shrimp myelinated nerve fibers". The ... Günther J (August 1976). "Impulse conduction in the myelinated giant fibers of the earthworm. Structure and function of the ... Hsu K, Tan TP, Chen FS (1975). "Saltatory conduction in the myelinated giant fiber of shrimp (Penaeus orientalis)". ...
They are all innervated by Aβ fibers, except the mechanorecepting free nerve endings, which are innervated by Aδ fibers. ... As all these types of mechanoreceptors are myelinated, they can rapidly transmit sensory information regarding joint positions ... Each muscle spindle consists of sensory nerve endings wrapped around special muscle fibers called spindle fibers (also called ... The Merkel nerve endings (also known as Merkel discs) detect sustained pressure. The lamellar corpuscles (also known as ...
The optimal ratio of axon diameter divided by the total fiber diameter (which includes the myelin) is 0.6.[20] ... Two oligodendrocyte cell bodies are clearly visible as well as several myelinated axons. These are hollow tubes and so appear ... Oligodendrocytes interact closely with nerve cells and provide trophic support by the production of glial cell line-derived ... Oligodendrocytes form the electrical insulation around the axons of CNS nerve cells. ...
Marner L, Nyengaard JR, Tang Y, Pakkenberg B. (2003Marked loss of myelinated nerve fibers in the human brain with age. J Comp ... கோடிக்கணக்கான மயலின் உடைய நரம்பிழைகள் (myelinated fibre) வெண்பொருளையும், பெருமூளைப் புறணியையும் இணைக்கின்றன. 20 வயதான ஆணின் ...
It is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain.[1] It has up to six layers of nerve ... In contrast to gray matter that is formed from neurons and their unmyelinated fibers, the white matter below them is formed ... predominantly by myelinated axons interconnecting neurons in different regions of the cerebral cortex with each other and ...
... s have Aα axons, which are large-caliber, heavily myelinated fibers that conduct action potentials rapidly. ... some of which contain the cell bodies of neurons belonging to the cranial nerves. Not all cranial nerve nuclei contain α-MNs; ... Alpha motor neurons send fibers that mainly synapse on extrafusal muscle fibers. Other fibers from α-MNs synapse on Renshaw ... By contrast, gamma motor neurons have Aγ axons, which are slender, lightly myelinated fibers that conduct less rapidly. ...
"Evidence for saltatory conduction in peripheral myelinated nerve-fibers". Journal of Physiology. 108 (3): 315-39. doi:10.1113/ ... Tasaki I (1939). "Electro-saltatory transmission of nerve impulse and effect of narcosis upon nerve fiber". Am. J. Physiol. 127 ... "Direct determination of membrane resting potential and action potential in single myelinated nerve fibers". Journal of ... Hursh JB (1939). "Conduction velocity and diameter of nerve fibers". American Journal of Physiology. 127: 131-39.. ...
Michael A Henry, et al, Unmyelinated nerve fibers in the human dental pulp express markers for myelinated fibers and show ... Key factors in testing are the enamel and dentine thickness and the number of nerve fibers underlying the pulp. Pulp nerve ... The dull aches are associated with C-fibers and slow Aδ-fibers. As inflammation intensifies, the A-fibers are increasingly ... C-fiber innervation and Aδ-fibers are polymodal receptors that are sensitive to capsaicin and inflammatory mediators.[7] ...
Myelination of nerve fibers[edit]. The complex changes that the Schwann cell undergoes during the process of myelination of ... Nodes of Ranvier (/ˌrɑːnviˈeɪ/ RAHN-vee-AY, /ˈrɑːnvieɪ/ -⁠ay),[1] also known as myelin-sheath gaps, occur along a myelinated ... Nerve conduction in myelinated axons is referred to as saltatory conduction (from the Latin saltare "to hop or to leap") due to ... Soon afterwards, he discovered gaps in sheaths of nerve fibers, which were later called the Nodes of Ranvier. This discovery ...
1° (Free nerve ending → A delta fiber) → 2° (Anterior white commissure → Lateral and Anterior Spinothalamic tract → Spinal ... made up of myelinated axons, constitute white matter. ... A bundle of nerve fibers (axons) connecting neighboring or ... sensory decussation/arcuate fibers (Posterior external arcuate fibers, Internal arcuate fibers) → Medial lemniscus/Trigeminal ... 1° (Group C nerve fiber → Spinoreticular tract → Reticular formation) → 2° (MD of Thalamus) → 3° (Cingulate cortex) ...
All nerve fibers are sensitive to LAs, but due to a combination of diameter and myelination, fibers have different ... Although type B fibers are thicker than type C fibers, they are myelinated, thus are blocked before the unmyelinated, thin C ... Peripheral nerve block is injection of LA in the vicinity of a peripheral nerve to anesthetize that nerve's area of innervation ... Small and large peripheral nerves can be anesthetized individually (peripheral nerve block) or in anatomic nerve bundles ( ...
Thus, not all neurons correspond to the stereotypical motor neuron with dendrites and myelinated axons that conduct action ... Synapses are gaps between nerve cells. These cells convert their electrical impulses into bursts of neurochemical relayers, ... modulate synaptic connections between presynaptic terminals of motor neuron endplates and muscle fibers at neuromuscular ... Some neurons such as photoreceptor cells, for example, do not have myelinated axons that conduct action potentials. Other ...
Diagnostic tests include electromyography (EMG) and nerve conduction studies (NCSs), which assess large myelinated nerve fibers ... These nerves are not under a person's conscious control and function automatically. Autonomic nerve fibers form large ... and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the ... the type of nerve fiber predominantly affected (motor, sensory, autonomic), or the process affecting the nerves; e.g., ...
The axons (as afferent nerve fibers) of sensory neurons connect with, or respond to, various receptor cells. These sensory ... Merkel and bulbous cells - slow-response - are myelinated; the rest - fast-response - are not. All of these receptors are ... if sensation is in parts of the head or neck not covered by the cervical nerves, it will be the trigeminal nerve ganglia or the ... Merkel cell nerve endings are found in the basal epidermis and hair follicles; they react to low vibrations (5-15 Hz) and deep ...
Two-thirds of an octopus's neurons are found in the nerve cords of their arms. Octopus arms show a variety of complex reflex ... It consists of the grey matter, or neuronal cell bodies and unmyelinated fibers, surrounding the deeper white matter ( ... myelinated axons) in the cerebrum. The neocortex is smooth in rodents and other small mammals, whereas in primates and other ... process that will eventually be explained in terms of molecular signaling pathways used by interacting populations of nerve ...
Johnson, Don H.; Swami, Ananthram (1983-08-01). "The transmission of signals by auditory‐nerve fiber discharge patterns". The ... Neuron and myelinated axon, with signal flow from inputs at dendrites to outputs at axon terminals ... Taberner, Annette M.; Liberman, M. Charles (2005-01-01). "Response Properties of Single Auditory Nerve Fibers in the Mouse". ... "Analysis of discharges recorded simultaneously from pairs of auditory nerve fibers". Biophysical Journal. 16 (7): 719-734. ...
... whereas Groups A and B are myelinated. Group C fibers include postganglionic fibers in the autonomic nervous system (ANS), and ... C fibers are one class of nerve fiber found in the nerves of the somatic sensory system.[1] They are afferent fibers, conveying ... Group C nerve fibers are one of three classes of nerve fiber in the central nervous system (CNS) and peripheral nervous system ... After a nerve lesion of either C fibers or Aδ fibers, they become abnormally sensitive and cause pathological spontaneous ...
In fact, all cells expend a large fraction of the ATP they produce (typically 30% and up to 70% in nerve cells) to maintain ... Dutka TL, Lamb GD (September 2007). "Na+-K+ pumps in the transverse tubular system of skeletal muscle fibers preferentially use ... pump on myelinated axons, in human brain, was demonstrated to be along the internodal axolemma, and not within the nodal ... Skou JC (February 1957). "The influence of some cations on an adenosine triphosphatase from peripheral nerves". Biochimica et ...
... l tissues are frequently innervated by sensory nerve endings. These include myelinated as well as unmyelinated nerves. ... These collagen fibers are produced by fibroblasts located within the fascia.[1] ... It serves as a storage medium of fat and water; as a passageway for lymph, nerve and blood vessels; and as a protective padding ... A fascial compartment is a section within the body that contains muscles and nerves and is surrounded by fascia. In the human ...
Lamina VI or SGP, the stratum griseum profundum ("deep gray layer"), consists of loosely packed neurons and myelinated fibers. ... Scheme showing central connections of the optic nerves and optic tracts. (Superior colliculus visible near center.) ... Lamina I or SZ, the stratum zonale, is a thin layer consisting of small myelinated axons together with marginal and horizontal ... Lamina V or SAI, the stratum album intermedium ("intermediate white layer"), consists mainly of fibers from various sources. ...
The fibers transmitting signals to the brain are called afferent (or sensory) fibers. Nerves can be afferent, efferent or mixed ... White matter in the brain is myelinated neurons, while grey matter contains mostly cell soma, dendrites, and unmyelinated ... which innervates the body through spinal nerves. Nervous fibers transmitting signal from the brain are called efferent fibers. ... Anatomically, the majority of afferent and efferent nerves (with the exception of the cranial nerves) are connected to the ...
... which are often bundled together in what are called nerve fiber tracts. A myelinated axon is wrapped in a fatty insulating ... There are also unmyelinated axons). Myelin is white, making parts of the brain filled exclusively with nerve fibers appear as ... He postulated that nerves activate muscles mechanically by carrying a mysterious substance he called pneumata psychikon, ... Nervous system of a generic bilaterian animal, in the form of a nerve cord with segmental enlargements, and a "brain" at the ...
Marner L, Nyengaard JR, Tang Y, Pakkenberg B (Jul 2003). "Marked loss of myelinated nerve fibers in the human brain with age". ... Men were found to have a total myelinated fiber length of 176 000 km at the age of 20, whereas in women the total length was ... Testosterone has been found to act as an antagonist of the TrkA and p75NTR, receptors for the neurotrophin nerve growth factor ... resistance exercise and fiber type". The Journal of Steroid Biochemistry and Molecular Biology. 110 (1-2): 130-37. doi:10.1016/ ...
... whereas a single nerve fiber innervates many outer hair cells. Inner hair cell nerve fibers are also very heavily myelinated, ... Nerve fiber innervation is much denser for inner hair cells than for outer hair cells. A single inner hair cell is innervated ... "Cranial Nerve VIII. Vestibulocochlear Nerve". Meddean. Loyola University Chicago. Retrieved 2008-06-04.. ... Neurons of the auditory or vestibulocochlear nerve (the eighth cranial nerve) innervate cochlear and vestibular hair cells.[19] ...
... made up largely of myelinated nerve fibers running to and from the cortex. Embedded within the white matter-which is sometimes ... CF: Climbing fiber. • CFC: Climbing fiber collateral. • GC: Granule cell. • PF: Parallel fiber. • PC: Purkinje cell. • GgC: ... The mossy fiber and climbing fiber inputs each carry fiber-specific information; the cerebellum also receives dopaminergic, ... mossy fibers and climbing fibers (which enter the cerebellum from outside), and parallel fibers (which are the axons of granule ...
... myelinated somatic nerves, unmyelinated motor nerve terminals, nicotinic acetylcholine receptors, the motor end plate, and the ... It reduces skeletal muscle strength by inhibiting the excitation-contraction coupling in the muscle fiber. In normal muscle ... Normally, a nerve impulse arrives at the motor nerve terminal, initiating an influx of calcium ions, which causes the ...
... myelinated) fibers in 1959. The fast (myelinated) fibers block the slow (unmyelinated) fibers, "fast blocks slow".[3] ... Afferent pain-receptive nerves, those that bring signals to the brain, comprise at least two kinds of fibers - a fast, ... also receive input from Aβ fibers.[7] The nonnociceptive fibers indirectly inhibit the effects of the pain fibers, 'closing a ... Gate control theory asserts that activation of nerves which do not transmit pain signals, called nonnociceptive fibers, can ...
However, the myelin layer does not ensure a perfect regeneration of the nerve fiber. Some regenerated nerve fibers do not find ... non-myelinated axons (or intermittently myelinated axons, meaning axons with long non-myelinated regions between myelinated ... Myelinated fibers lack voltage-gated sodium channels along the myelinated internodes, exposing them only at the nodes of ... In unmyelinated fibers, electrical impulses (action potentials) travel as continuous waves, but, in myelinated fibers, they " ...
Marner, L; Nyengaard, JR; Tang, Y; Pakkenberg, B (2003). "Marked loss of myelinated nerve fibers in the human brain with age". ...
Conduction in myelinated nerve fibers was blocked by the application of local pressure to the superficial radial nerve. The ... A Role for Nociceptive, Myelinated Nerve Fibers in Itch Sensation. Matthias Ringkamp, Raf J. Schepers, Steven G. Shimada, Lisa ... A Role for Nociceptive, Myelinated Nerve Fibers in Itch Sensation. Matthias Ringkamp, Raf J. Schepers, Steven G. Shimada, Lisa ... A Role for Nociceptive, Myelinated Nerve Fibers in Itch Sensation Message Subject (Your Name) has forwarded a page to you from ...
Asymmetrical displacement currents and Na currents of single myelinated nerve fibers ofXenopus laevis were studied in the ... Asymmetrical displacement currents and Na currents of single myelinated nerve fibers ofXenopus laevis were studied in the ... Temperature dependence of gating current in myelinated nerve fibers. *Peter Jonas1 ... Jonas, P. Temperature dependence of gating current in myelinated nerve fibers. J. Membrain Biol. 112, 277-289 (1989). https:// ...
Neuroretinitis Secondary to Bartonella Henselae in a Patient with Myelinated Retinal Nerve Fibers: Diagnostic Dilemmas and ... in a patient with myelinated retinal nerve fibers (MRNFs). Methods: A 56-year-old male presented for a consultation, because of ... The presence of myelinated nerve sheath in combination with the expected swelling in neuroretinitis may have caused an ...
This thesis is concerned with the development of a new distributed-parameter model of the myelinated nerve fiber that includes ... "A distributed-parameter model of the myelinated nerve fiber." (1989) Diss., Rice University. https://hdl.handle.net/1911/16506. ... was performed and tables containing the biophysical properties of the amphibian and mammalian myelinated nerve fibers were ... Physiological conduction velocities of 20.2 m/s at 20$\sp\circ$C for a 15$\mu$m diameter amphibian fiber and 57.6 m/s at 37$\sp ...
Myelinated Nerve Fibers and Astroglia Visualized in a Sagittal Section of Rat Brain. Myelin was targeted in the sagittal rat ... Myelinated Nerve Fibers and Astroglia Visualized in a Sagittal Section of Rat Brain ...
View this Crosssection Of A Nerve Fiber In Intestinal Connective Tissue Showing Both Myelinated And Unmyelinated Axons Tem ... Cross-section of a nerve fiber in intestinal connective tissue showing both myelinated and unmyelinated axons. TEM X47,000. ...
"Nerve Fibers, Myelinated" by people in this website by year, and whether "Nerve Fibers, Myelinated" was a major or minor topic ... NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves. ... A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated ... "Nerve Fibers, Myelinated" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical ...
... Nerve fibers in the retina, which are covered with patches of a fat like substance (arrows) called ...
... myelinated nerve fibers, neck, nerve cell, nerve cell body, nerve cells, nerve fibers, nerves, nervous tissue, network of ... transverse nerve fibers, trigeminal nerves, trochlear nerves, trunk, tumor, type of fish, unmyelinated fibers, uppermost part ... Tag Archives: myelinated nerve fibers. A Glance into the Human Brain. Posted on 04/12/2014. by Aditya Sardana ... facial nerves, Facts about the Human Brain, fear, feedback to the motor areas, feelings of pleasure, fibers, fibers of nervous ...
The effects of aging on myelinated nerve fibers of the central nervous system are complex. Many myelinated nerve fibers in ... Other myelinated nerve fibers are affected differently, because only their sheaths degenerate, leaving the axons intact. Such ... The Effects of Normal Aging on Myelinated Nerve Fibers in Monkey Central Nervous System. ... While the loss of some myelinated nerve fibers leads to some disconnections, the degeneration of other myelin sheaths and the ...
... are retinal nerve fibers anterior to the lamina cribrosa that, unlike normal retinal nerve fibers, have a myelin sheath. ... Disappearance of MRNF have also been reported after surgery and insults to the optic nerve. ... Myelinated Retinal Nerve Fiber Layer. Myelinated retinal nerve fiber layers (MRNF) are retinal nerve fibers anterior to the ... Figure 2. OCT in which red arrows identify the hyperreflective appearance of a myelinated retinal nerve fiber layer.. ...
The bottom photograph is of a normal optic nerve. the top four demonstrate myelinated nerve fibers. Nerve fibers are usually ... MYELINATED NERVE FIBERS. The bottom photograph is of a normal optic nerve. the top four demonstrate myelinated nerve fibers. ... Nerve fibers are usually insulated with myelin, that aids in transmission of nerve impulses. Usually this insulation ends as ... the fibers enter the eyeball. But occasionally, as is the case below, the insulation will continue, and you can see it as the ...
NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves. ... The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and ... Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers ( ... A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. ...
Not all patients with unilateral peripapillary myelinated nerve fibers, an abnormal macula, and myopia will have refractory ... Not all patients with unilateral peripapillary myelinated nerve fibers, an abnormal macula, and myopia will have refractory ... Not all patients with unilateral peripapillary myelinated nerve fibers, an abnormal macula, and myopia will have refractory ... Not all patients with unilateral peripapillary myelinated nerve fibers, an abnormal macula, and myopia will have refractory ...
Tags: monitoring myelinated nerve fiber layer, myelinated nerve fiber layer, vision loss with myelinated nerve fiber layer, ... Myelinated nerve fiber layer is a benign finding where the myelin sheath that typically lines and insulates the optic nerve ... Studies show that myelinated nerve fiber layer is very rare (less than one percent of the population!). The presence of myelin ... It is unusual but possible to develop myelinated nerve fiber layer changes after birth in cases of ocular tumors or trauma, but ...
Myelinated nerve fiber in the largest biology dictionary online. Free learning resources for students covering all major areas ... Nerve fiber enveloped by a sheath of myelin believed to be associated with saltatory conduction, which is a physiological ... mechanism for faster conduction of action potential along the nerve fiber.. Supplement. See also: dyemyelinated nerve. ...
Jonas, P. M. (1989). Temperature dependence of gating current in myelinated nerve fibers. Journal of Membrane Biology, 112(3), ... P. M. Jonas, "Temperature dependence of gating current in myelinated nerve fibers," Journal of Membrane Biology, vol. 112, no. ... Jonas, Peter M. "Temperature Dependence of Gating Current in Myelinated Nerve Fibers." Journal of Membrane Biology 112, no. 3 ( ... Jonas, Peter M. "Temperature Dependence of Gating Current in Myelinated Nerve Fibers." Journal of Membrane Biology, vol. 112, ...
Follow-up data are presented on a previously described child in whom myelinated nerve fibers presumably developed 5½ months ... the myelinated nerve fibers have progressively enlarged. Five years after surgery, myelinated nerve fibers appeared in the ... Follow-up data are presented on a previously described child in whom myelinated nerve fibers presumably developed 5½ months ... An additional two cases of documented acquired myelinated nerve fibers without any predisposing factors are reported. ...
Atrophy of myelinated nerve fibers in pituitary adenoma. Together they form a unique fingerprint. * Myelinated Nerve Fibers ... Atrophy of myelinated nerve fibers in pituitary adenoma. Amod Gupta, Birgit Khandalavala, R. K. Bansal, I. S. Jain, S. P.S. ... Atrophy of myelinated nerve fibers in pituitary adenoma. / Gupta, Amod; Khandalavala, Birgit; Bansal, R. K.; Jain, I. S.; ... title = "Atrophy of myelinated nerve fibers in pituitary adenoma",. abstract = "A one-eyed patient was referred as a case of ...
... and non-myelinated (C) fibres in the common peroneal nerve of rabbits were studied during and after acute, graded compression ... of the nerve at 200 or 400 mmHg applied for 2 h or during ischaemia created by nitrogen inhalation or aortic occlusion. Comp … ... Nerve Fibers / physiology* * Nerve Fibers, Myelinated / physiology* * Neural Conduction* / drug effects * Nitrogen / ... Effects of nerve compression or ischaemia on conduction properties of myelinated and non-myelinated nerve fibres. An ...
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9.5 to identify all nerve fibers, tyrosine hydroxylase (TH) to identify sympathetic fibers, contactin-associated protein (caspr ... of NaCh clusters in unmyelinated fibers suggests an inherent capacity for the unmyelinated segments of myelinated fibers to ... and in fibers with NFH that lack Schwann cell associations. The expression of NFH in most axons suggests a myelinated origin ... yet recent findings in experimental animals suggest many pulpal afferents originate from fibers that are myelinated at more ...
Treatment for Myelinated Retinal Nerve Fiber layer (NMNF) johnmaydeck1969 Hi Dr. We are supporting a few orphans in Cambodia. ...
Modeling the electrical activity in myelinated nerve fibers Towards the electrophysiological validation of neuronal bridges * ... sciatic nerve in frog, b) giant lateral axons and giant medial axon in earthworm, and c) infraorbital nerve in rats. Results ... The proposed model could become a valuable tool to determine the percentage of functionally connected fibers through neural ... a simplified empirical model is proposed to describe the action potential generation and conduction through myelinic fibers. ...
... ... All patients presented extensive peripapillary myelinated nerve fibers associated with myopic anisometropia. After routine ... Myelination of optic nerve fibers terminate at lamina cribrosa. Yet in some patients, myelination progresses into the ... Unilateral extensive myelination of the peripapillary nerve fibers may be associated with anisometropic myopia, strabismus, and ...
... Posted on September 29, 2017 at ... In mammalian peripheral nerves, unmyelinated C-fibers outnumber myelinated A-fibers usually. a combined 129 C57Bl6 history and ... 1ACF). An identical pattern was seen in another cutaneous nerve analyzed, the sural nerve. The mean C:A-fiber proportion in the ... Beliefs for C:A-fiber proportion in ... Desk 1 Overview of Saphenous, Sural, and Common Peroneal Nerve Fibers Data for every ...
In the present study, a 10 mm long gap in the median nerve was repaired with 12 mm SilkBridgeTM conduit and evaluated at middle ... In the present study, a 10 mm long gap in the median nerve was repaired with 12 mm SilkBridge conduit and evaluated at middle ... conduit led to a very good functional and morphological recovery of the median nerve, similar to that observed with the ... The SilkBridgeTM conduit led to a very good functional and morphological recovery of the median nerve, similar to that observed ...
However, the myelin layer does not ensure a perfect regeneration of the nerve fiber. Some regenerated nerve fibers do not find ... non-myelinated axons (or intermittently myelinated axons, meaning axons with long non-myelinated regions between myelinated ... Myelinated fibers lack voltage-gated sodium channels along the myelinated internodes, exposing them only at the nodes of ... In unmyelinated fibers, electrical impulses (action potentials) travel as continuous waves, but, in myelinated fibers, they " ...
OCT in a Myelinated Retinal Nerve Fiber Syndrome with Reduced Vision. Bass, Sherry J.; Westcott, Jacqueline; Sherman, Jerome ...
Anatomy of a Nerve More than ten thousand million nerve cells and their fibers, or axons, make up the nervous system. The axons ... They are called myelinated nerve fibers. The myelinated sheath has regular indentations along its length called the nodes of ... Anatomy of a Nerve. More than ten thousand million nerve cells and their fibers, or axons, make up the nervous system. The ... and motor fibers, which carry information to the central nervous system of the body. The nerve fibers which carry information ...
  • Neuroretinitis Secondary to Bartonella Henselae in a Patient with Myelinated Retinal Nerve Fibers: Diagnostic Dilemmas and Treatment. (nih.gov)
  • To report an unusual case of Bartonella henselae neuroretinitis (BHNR) in a patient with myelinated retinal nerve fibers (MRNFs). (nih.gov)
  • Myelinated retinal nerve fiber layers (MRNF) are retinal nerve fibers anterior to the lamina cribrosa that, unlike normal retinal nerve fibers, have a myelin sheath. (eyewiki.org)
  • The German pathologist Rudolf Virchow was the first to describe myelinated retinal nerve fibers, writing in 1856 that the "retina was white, very thick and wrinkled. (eyewiki.org)
  • A one-eyed patient was referred as a case of amblyopia secondary to myelinated retinal nerve fibers. (nebraska.edu)
  • Yet in some patients, myelination progresses into the peripapillary retinal nerve fibers and may affect the visual acuity. (maltepe.edu.tr)
  • Acquired bilateral myelinated retinal nerve fibers after unilateral optic nerve sheath fenestration in a child with idiopathic intracranial hypertension. (duke.edu)
  • PURPOSE: To report the unusual development of bilateral myelinated retinal nerve fibers (MRNF) adjacent to the optic nerve in a child after treatment of idiopathic intracranial hypertension (IIH) with unilateral optic nerve sheath fenestration (ONSF) and to discuss the etiology of acquired MRNF. (duke.edu)
  • It also covers intraocular tumors and congenital conditions such as myelinated retinal nerve fibers. (springer.com)
  • This thesis is concerned with the development of a new distributed-parameter model of the myelinated nerve fiber that includes an adequate representation of the anatomical complexity present at the node of Ranvier, considers the peri-axonal conductance pathway and includes active ionic channels in the axolemmal membrane beneath the myelin sheath. (rice.edu)
  • The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. (umassmed.edu)
  • Myelinated nerve fiber layer is a benign finding where the myelin sheath that typically lines and insulates the optic nerve when it exists the eye, persist even inside the eye. (eyedolatryblog.com)
  • Normally, the myelin sheath stops before the nerve enters the eye because myelin (the dense white material you see above the nerve in this photo) will prevent light information from reaching any retinal cells underneath it. (eyedolatryblog.com)
  • Rather, each myelin sheath insulates the axon over a single long section and, in general, each axon comprises multiple long myelinated sections separated from each other by short gaps called nodes of Ranvier . (wikipedia.org)
  • The discontinuous structure of the myelin sheath results in saltatory conduction , whereby the action potential "jumps" from one node of Ranvier, over a long myelinated stretch of the axon called the internode, before "recharging" at the next node of Ranvier, and so on, until it reaches the axon terminal . (wikipedia.org)
  • When NRG1-erbB signaling was blocked, the mice had more oligodendrocytes than normal mice, but these cells had fewer branches and formed a significantly thinner myelin sheath around nerve fibers. (schizophrenia.com)
  • a. axon, axolemma, axoplasm b. cell membrane c. cyton d. dendrites e. myelin sheath f. nodes of Ranvier, internodes g. terminal axon fibers h. (cuny.edu)
  • Cross-section of a nerve fiber in intestinal connective tissue showing both myelinated and unmyelinated axons. (gettyimages.com)
  • Other myelinated nerve fibers are affected differently, because only their sheaths degenerate, leaving the axons intact. (bu.edu)
  • Indeed, not only do these neuroglial cell remyelinate axons, with age they also continue to add lamellae to the myelin sheaths of intact nerve fibers, so that sheaths become thicker. (bu.edu)
  • While the loss of some myelinated nerve fibers leads to some disconnections, the degeneration of other myelin sheaths and the subsequent remyelination of axons by shorter internodes slow down the rate conduction along nerve fibers. (bu.edu)
  • Here we use the human dental pulp and confocal microscopy to examine the staining relationships of neurofilament heavy (NFH), a protein commonly expressed in myelinated afferents, with other markers to test the possibility that unmyelinated pulpal afferents originate from myelinated axons. (biomedcentral.com)
  • Results show NFH expression in most PGP9.5 fibers except those with TH and include the broad expression of NFH in axons lacking MBP. (biomedcentral.com)
  • The expression of NFH in most axons suggests a myelinated origin for many pulpal afferents, while the presence of NaCh clusters in unmyelinated fibers suggests an inherent capacity for the unmyelinated segments of myelinated fibers to form NaCh accumulations. (biomedcentral.com)
  • Taken together, these results suggest that many of the unmyelinated axons within the dental pulp originate from parent axons that are myelinated at more proximal locations. (biomedcentral.com)
  • The present study examines the expression of neurofilament heavy (NFH) protein, a protein commonly expressed within sensory neurons that give rise to myelinated afferents [ 12 ], to test the hypothesis that many of the unmyelinated pulpal afferents within the human dental pulp originate from myelinated axons. (biomedcentral.com)
  • In this study we take the opportunity to characterize the fibers with NaCh accumulations at non-nodal sites to test the hypothesis that the unmyelinated segments of myelinated axons show an inherent ability to cluster NaChs. (biomedcentral.com)
  • The model's electrophysiological validation was performed through qualitative analysis in three experimental situations that call for action potential: a) sciatic nerve in frog, b) giant lateral axons and giant medial axon in earthworm, and c) infraorbital nerve in rats. (mdp.edu.ar)
  • 5 mm), a graft must be used to bridge the gap between the two nerve stumps and to guide regenerating axons towards target organs. (frontiersin.org)
  • Myelin is a lipid -rich (fatty) substance that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials ) are passed along the axon. (wikipedia.org)
  • In the CNS, axons carry electrical signals from one nerve cell body to another. (wikipedia.org)
  • In vertebrates, not all axons are myelinated. (wikipedia.org)
  • More than ten thousand million nerve cells and their fibers, or axons, make up the nervous system. (youtube.com)
  • The axons are grouped together in nerve trunks containing sensory fibers, which conduct information from the sensory organs to the central nervous system, and motor fibers, which carry information to the central nervous system of the body. (youtube.com)
  • The peripheral axons of auditory nerve fibers form synaptic connections with the hair cells of the cochlea via ribbon synapses using the neurotransmitter glutamate . (wikipedia.org)
  • These central axons exit the cochlea at its base and form a nerve trunk , which, in humans, is approximately one inch long. (wikipedia.org)
  • In mammals, the axons from each cochlear nerve terminate in the cochlear nuclear complex that is ipsilaterally located in the medulla of the brainstem. (wikipedia.org)
  • Peripheral nerves contain fascicles of nerve fibers consisting of axons. (nysora.com)
  • In peripheral nerve fibers, axons are ensheathed by Schwann cells, which may or may not form myelin around the axons, depending on their diameter. (nysora.com)
  • Optic nerve head drusen (ONHD) represent congenital anomaly, which is a form of calcium degeneration of optic nerve head axons. (intechopen.com)
  • By reducing intraocular pressure, the compression to the optic nerve axons decreases, thus improving perfusion of the optic nerve head. (intechopen.com)
  • This is a form of calcium degeneration of the axons of the optic nerve head (ONH). (intechopen.com)
  • We have recently developed a method for imaging myelinated axons in vivo (Spectral confocal reflectance microscopy SCoRe), which we are currently using to explore questions related to myelin's role in degeneration and regeneration. (yale.edu)
  • Label-free in vivo imaging of myelinated axons in health and disease with spectral confocal reflectance microscopy. (yale.edu)
  • The reasons for the impossibility of treating transected axons using surgical sutures are discussed, and finally the cause of the absence of swelling properties in myelinated fibers with hypotension environment is solved. (novapublishers.com)
  • B f's myelinated preganglionic autonomic axons having a fiber diameter less than 3 μm and a conduction velocity of 3 to 15 meters per second. (thefreedictionary.com)
  • These include cutaneous and subcutaneous fibers, somesthetic and proprioceptive fibers, and motor axons of equivalent diameter. (medscape.com)
  • Stimulation produces an action potential that travels up the axon toward the spinal cord and past the cell bodies of the sensory axons of the large-fiber sensory system in the dorsal root ganglia to the ipsilateral posterior columns of the spinal cord. (medscape.com)
  • This protein is localized at the juxtaparanodes of myelinated axons, and mediates interactions between neurons and glia during nervous system development and is also involved in localization of potassium channels within differentiating axons. (nih.gov)
  • Required, with CNTNAP1, for radial and longitudinal organization of myelinated axons. (nih.gov)
  • The brain plays the role of the control tower or control center of the human body, and relies on a vast network of nerves (bundles of fibers of nervous tissue carrying impulses) spread throughout the body. (adidarwinian.com)
  • Nerves can be compared to the electrical wiring as they carry electrical impulses. (adidarwinian.com)
  • Nerve fibers are usually insulated with myelin, that aids in transmission of nerve impulses. (sonorandeserteye.com)
  • Neurons transmit nerve impulses to and from the central nervous system (CNS), thereby integrating motor and sensory functions. (nysora.com)
  • accelerating f's ( accelerator f's ) adrenergic fibers that transmit the impulses that accelerate the heart beat. (thefreedictionary.com)
  • As a result, the nerve fibers conducted electrical impulses more slowly, the researchers found. (schizophrenia.com)
  • 14. Describe why nerve impulses travel at higher velocities in myelinated nerve fibers compared with unmyelinated nerve fibers. (cuny.edu)
  • Plays a role in the formation of functional distinct domains critical for saltatory conduction of nerve impulses in myelinated nerve fibers. (nih.gov)
  • In mammalian peripheral nerves, unmyelinated C-fibers outnumber myelinated A-fibers usually. (researchhunt.com)
  • Peripheral nerves are widely spread throughout the body and are therefore highly vulnerable to injury as a consequence of multiple causes, i.e., car accidents, domestic falls, military and sports injuries. (frontiersin.org)
  • The aim of this study was to determine whether aerobic exercise (AE) in old age contributes to improving the morphologies of myelinated fibers (MFs) in peripheral nerves as well as capillaries. (elsevier.com)
  • Levels of BDNF and VEGF in the serum and peripheral nerves were analyzed via enzyme-linked immunosorbent assay. (elsevier.com)
  • In conclusion, our study indicates that regular AE induces enlargement of the capillaries and thickens the myelin in aged peripheral nerves, likely via .complementary process involving BDNF and VEGF. (elsevier.com)
  • NEW & NOTEWORTHY Accumulating evidence indicates that age-related sarcopenia is accompanied by the degeneration of myelinated fibers (MFs) in peripheral nerves. (elsevier.com)
  • This chapter provides basis for understanding of the structure, classification, and organization of the peripheral nerves and insight into how the characteristics of the peripheral nerves ( Figure 1 ) relate to the clinical practice of regional anesthesia. (nysora.com)
  • The PNS consists of peripheral nerves (craniospinal, somatic, autonomic) with their associated ganglia and connective tissue investments. (nysora.com)
  • Already partially dysfunctional peripheral nerves may be more susceptible to local compression. (medscape.com)
  • SEPs provide information concerning the integrity of the pathway through the brain, brain stem, spinal cord, dorsal roots, and peripheral nerves. (medscape.com)
  • Paralyzed rabbits had pathological changes in their peripheral nerves identical with those present in Guillain-Barré syndrome. (pnas.org)
  • Immunization of mice with the lipooligosaccharide generated a mAb that reacted with GM1 and bound to human peripheral nerves. (pnas.org)
  • GBS was considered a demyelinating disease of the peripheral nerves, but the existence of primary "axonal GBS" has been confirmed and is now widely recognized ( 3 , 4 ). (pnas.org)
  • To verify that molecular mimicry between an environmental agent and the peripheral nerves causes GBS, we sensitized animals with C. jejuni LOS and produced a replica of human GBS, generated anti-GM1 mAb by immunization with the LOS, and determined the distribution of GM1 in human spinal nerve roots. (pnas.org)
  • Human brain is comprised of about 100 billion neurons or nerve cells. (adidarwinian.com)
  • Knowledge concerning the relative contribution of pulpal innervation from sensory neurons that give rise to either myelinated or unmyelinated peripheral nerve fibers is important since the fiber type strongly influences the characteristic quality of pain experienced following peripheral nociceptor activation [ 13 - 15 ]. (biomedcentral.com)
  • The mechanism of simultaneous currents bidirectional axoplasm, disappearance streams and reappearance of the apical dendrites of pyramidal neurons in the brain during stress were revealed, as well as the causes of the similarity of nerve terminals regardless of their very different physiological functions. (novapublishers.com)
  • Not all patients with unilateral peripapillary myelinated nerve fibers, an abnormal macula, and myopia will have refractory amblyopia. (umn.edu)
  • Summers, CG , Romig, L & Lavoie, JD 1991, ' Unexpected good results after therapy for anisometropic amblyopia associated with unilateral peripapillary myelinated nerve fibers ', Journal of Pediatric Ophthalmology and Strabismus , vol. 28, no. 3, pp. 134-136. (umn.edu)
  • Lavoie, J. D. / Unexpected good results after therapy for anisometropic amblyopia associated with unilateral peripapillary myelinated nerve fibers . (umn.edu)
  • All patients presented extensive peripapillary myelinated nerve fibers associated with myopic anisometropia. (maltepe.edu.tr)
  • The presence of myelinated nerve sheath in combination with the expected swelling in neuroretinitis may have caused an irreversible mechanical nerve damage. (nih.gov)
  • A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. (umassmed.edu)
  • Nerve fiber enveloped by a sheath of myelin believed to be associated with saltatory conduction, which is a physiological mechanism for faster conduction of action potential along the nerve fiber . (biologyonline.com)
  • The nerve fibers which carry information quickly are enclosed in a thick sheath made of the fatty substance myelin. (youtube.com)
  • The myelinated sheath has regular indentations along its length called the nodes of Ranvier. (youtube.com)
  • The nonmyelinated nerve fibers, which carry information slowly, are grouped together and enclosed in a single sheath. (youtube.com)
  • Working with mice, the researchers blocked NRG1-erbB signaling in oligodendrocytes --the cells that form the fatty sheath, known as myelin, which insulates nerve fibers. (schizophrenia.com)
  • [1] The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. (wikipedia.org)
  • Once it reaches the axon terminal, this electrical signal provokes the release of a chemical message or neurotransmitter that binds to receptors on the adjacent post-synaptic cell (e.g., nerve cell in the CNS or muscle cell in the PNS) at specialised regions called synapses . (wikipedia.org)
  • Fiber diameter, myelin thickness, axon diameter, myelin perimeter, axon perimeter and G-ratio of the young and elderly groups for the three myelinated fiber sizes (large, medium, and small myelinated fibers). (biomedcentral.com)
  • Regression coefficients and intercepts indicate those of regression lines on total fiber diameter, myelin thickness, axon diameter, myelin perimeter, axon perimeter, and g-ratio for the young and elderly groups. (biomedcentral.com)
  • Both the peripheral process and the axon are myelinated . (wikipedia.org)
  • Each type I axon innervates only a single inner hair cell, but each inner hair cell is innervated by up to 30 such nerve fibers, depending on species and location within the cochlea. (wikipedia.org)
  • The nerve cell body, dendrites, and proximal part of the axon are within the CNS. (nysora.com)
  • This is not surprising given the strong evidence for interaction between myelin and axon gene expression in development and after experimental nerve lesions. (medscape.com)
  • As an action potential (nerve impulse) travels down an axon there is a change in polarity across the membrane of the axon. (wikipedia.org)
  • Physiological conduction velocities of 20.2 m/s at 20$\sp\circ$C for a 15$\mu$m diameter amphibian fiber and 57.6 m/s at 37$\sp\circ$C for a 17.5$\mu$m diameter mammalian fiber were achieved. (rice.edu)
  • [7] Both myelinated and unmyelinated fibers within a region of MRNF have been shown to be larger in diameter than fibers within normal retina. (eyewiki.org)
  • Although the morphometric data of myelinated fibers showed that about 44% having larger diameter between 3 to 4 µm and the mean value was 4.5 µm. (bvsalud.org)
  • The unmyelinated fibers showed the largest diameter (62%) varying from 0.25 to 0.75 µm. (bvsalud.org)
  • The smallest diameter was obtained in 44% of unmyelinated fibers which the diameter ranges from 0.2 to 0.4 µm.Then maximum value obtained was 1 µm and the minimum was 0.12 µm. (bvsalud.org)
  • The in vivo studies showed that chitin conduit combined with exosomes from GMSCs could significantly increase the number and diameter of nerve fibers and promote myelin formation. (hindawi.com)
  • or = 9.0 microm diameter) myelinated fibers than the saline treated nerves. (nih.gov)
  • Accornero N, Bini G, Lenzi GL, Manfredi M. Selective activation of peripheral nerve fibre groups of different diameter by triangular shaped stimulus pulses. (degruyter.com)
  • A f's myelinated fibers of the somatic nervous system having a diameter of 1 to 22 μm and a conduction velocity of 5 to 120 meters per second. (thefreedictionary.com)
  • alpha f's motor and proprioceptive fibers of the A type having conduction velocities of 70 to 120 meters per second and ranging from 13 to 22 micrometers in diameter. (thefreedictionary.com)
  • also, the unmyelinated fibers at the dorsal roots and at free nerve endings having a diameter of 0.3 to 1.3 μm and a conduction velocity of 0.6 to 2.3 meters per second. (thefreedictionary.com)
  • The stimulus activates predominantly the large-diameter, fast-conducting group in muscles and group II cutaneous fibers. (medscape.com)
  • Type A fibers are the myelinated fibers ranging from 1-22 um in diameter with Neural Conduction rates of 5-120 m/sec. (online-medical-dictionary.org)
  • Nerve selectivity: rapid firing, small diameter 'C' fibers and medium diameter, myelinated B sympathetic preganglionic fibers. (sporcle.com)
  • The chitin conduit was prepared and combined with the exosomes to repair rat sciatic nerve defect. (hindawi.com)
  • Histology, electrophysiology, and gait analysis were used to test the effects of exosomes on sciatic nerve function recovery in vivo. (hindawi.com)
  • Low dose intermittent (0.2 units thrice weekly) Toronto (regular) insulin was injected at the sciatic notch and knee near the left sciatic nerve of rats rendered diabetic with citrate buffered streptozotocin or nondiabetic rats given citrate only. (nih.gov)
  • Identical volumes of normal saline were injected near the contralateral right sciatic nerve. (nih.gov)
  • Metabotropic glutamate receptor 5 (mGluR5) protein increased after sciatic nerve section in ipsilateral L4 and L5 DRG neuronal profiles, with most of the increase occurring in myelinated A-fiber somata. (jneurosci.org)
  • mGluR5 also increased in lamina II of the ipsilateral spinal cord and the proximal sciatic nerve stump in this model. (jneurosci.org)
  • Interestingly, after partial sciatic nerve section, mGluR5 expression did not change in either L4 or L5 DRG neuronal profiles. (jneurosci.org)
  • Both spinal nerve ligation and sciatic nerve partial section produced significant mechanical and thermal hyperalgesia and tactile allodynia. (jneurosci.org)
  • After partial sciatic nerve section, the mGluR5-specific antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) had no effect on any of these behaviors. (jneurosci.org)
  • The ability to selectively stimulate Aα, Aβ-fibers and Aδ-fibers in an isolated rat sciatic nerve (SNR) was assessed. (degruyter.com)
  • Compound action potentials of both myelinated (A) and non-myelinated (C) fibres in the common peroneal nerve of rabbits were studied during and after acute, graded compression of the nerve at 200 or 400 mmHg applied for 2 h or during ischaemia created by nitrogen inhalation or aortic occlusion. (nih.gov)
  • In this respect, auditory nerve fibers are somewhat unusual in that action potentials pass through the soma. (wikipedia.org)
  • Two routine non-invasive electrophysiological techniques, before and after LILT, will be used for outcome measures: 1) antidromic sensory nerve action potentials (SNAPs) will be recorded from index finger in response to stimulation of the median nerve at the wrist and, 2) current perception threshold (CPT) testing of the index finger will be performed using the standard 2000 Hz, 250 Hz, and 5 Hz sinusoidal frequencies. (nova.edu)
  • It was concluded that action potentials (APs) were activated in the Aβ-fibers and Aδ-fibers along with a slight AP inhibition in the Aβ-fibers. (degruyter.com)
  • Asymmetrical displacement currents and Na currents of single myelinated nerve fibers of Xenopus laevis were studied in the temperature range from 5 to 24°C. The time constant of the on-response at E =4 mV, τ on , was strongly temperature dependent, whereas the amount of displaced charge at E =39 mV, Q on , was only slightly temperature dependent. (springer.com)
  • Histopathological analysis demonstrates that myelinated fibers are not confined to a patch or fascicle, and single myelinated fibers can be found in between fascicles of unmyelinated fibers. (eyewiki.org)
  • Myelinated nerve fibers are present in somatic and autonomic nerves. (umassmed.edu)
  • Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). (umassmed.edu)
  • To investigate the role of small myelinated afferents in nonhistaminergic itch, we tested, in psychophysical studies in humans, the effect of a differential nerve block on itch produced by intradermal insertion of spicules from the pods of a cowhage plant ( Mucuna pruriens ). (jneurosci.org)
  • [9] Due to its high prevalence, multiple sclerosis, which specifically affects the central nervous system (brain, spinal cord and optic nerve), is the best known disorder of myelin. (wikipedia.org)
  • and represent a major cause for morbidity, bringing to total or partial loss of motor, sensory and autonomic functions, with a devastating impact on a patients' quality of life, especially for severe nerve injury. (frontiersin.org)
  • To clarify the relationship between autonomic neuropathy and cardiovascular morbidity and mortality, it is important to evaluate both parasympathetic and sympathetic nerve functions. (diabetesjournals.org)
  • Autonomic dysfunction was revealed in 45-59% of uremic patients by autonomic nerve tests. (medscape.com)
  • brain, spinal cord and optic nerve) by glial cells called oligodendrocytes and in the peripheral nervous system (PNS) by glial cells called Schwann cells . (wikipedia.org)
  • 1. The nervous system is broadly organized into the central nervous system (CNS) - brain and spinal cord, and the peripheral nervous system (PNS) - the 12 pairs of cranial nerves and 31 pairs of spinal nerves. (cuny.edu)
  • The repair of a traumatic spinal cord injury comes with great difficulties, because the nerve tissue cannot simply form anew. (wingsforlife.com)
  • The nerve fiber bundles were verified inside of the connective tissue of lamina propria . (bvsalud.org)
  • These nerve fibers branched several times and into the connective tissue papillae they form a single or ramified sensory nerve endings . (bvsalud.org)
  • collagen f's ( collagenous f's ) the soft, flexible, white fibers that are the most characteristic constituent of all types of connective tissue, consisting of the protein collagen, and composed of bundles of fibrils that are in turn made up of smaller units ( microfibrils ) that show a characteristic crossbanding with a major periodicity of 65 nm. (thefreedictionary.com)
  • A fibrofatty connective tissue, which forms a bed for glands and skeletal muscle fibers and serves to anchor them. (anatomyatlases.org)
  • Other staining relationships studied included myelin basic protein (MBP), protein gene product (PGP) 9.5 to identify all nerve fibers, tyrosine hydroxylase (TH) to identify sympathetic fibers, contactin-associated protein (caspr) to identify nodal sites, S-100 to identify Schwann cells and sodium channels (NaChs). (biomedcentral.com)
  • Fibers with NFH and MBP show NaCh clusters at nodal sites as expected, but surprisingly, NaCh accumulations are also seen in unmyelinated fibers with NFH, and in fibers with NFH that lack Schwann cell associations. (biomedcentral.com)
  • The effects of exosomes on peripheral nerve regeneration in vitro were evaluated by coculture with Schwann cells and DRGs. (hindawi.com)
  • In the peripheral nervous system (PNS) myelinating Schwann cells synthesize large amounts of myelin protein zero (P0) glycoprotein, an abundant component of peripheral nerve myelin. (rero.ch)
  • Sympathetic nerve function was assessed by measurement of the vasoconstriction (VAC) index by laser Doppler perfusion imaging of a locally heated finger followed by indirect cooling. (diabetesjournals.org)
  • Sympathetic and parasympathetic nerve functions correlated in type 1 but not in type 2 diabetic patients. (diabetesjournals.org)
  • Although spectral analysis may have the advantage of assessing not only parasympathetic (high frequency variation) but also sympathetic (low frequency variation) nerve function ( 15 ), the advantage of spectral analysis has recently been challenged ( 16 ). (diabetesjournals.org)
  • To investigate sympathetic nerve function, tests other than spectral analysis may be preferred. (diabetesjournals.org)
  • To obtain a convenient and quantitative test of sympathetic nerve function, we have developed a laser Doppler perfusion imaging (LDPI) test in which alterations in finger skin blood flow upon local heating followed by indirect cooling are evaluated by assessment of the vasoconstriction (VAC) index. (diabetesjournals.org)
  • When the VAC index was compared before and after sympathectomy, we could clearly show that the VAC index is a test of sympathetic nerve function ( 17 ). (diabetesjournals.org)
  • Anterior or posterior nerve roots carry sympathetic outflow? (brainscape.com)
  • adrenergic f's nerve fibers of the sympathetic nervous system that liberate norepinephrine (and possibly small amounts of epinephrine ) at a synapse when a nerve impulse passes. (thefreedictionary.com)
  • The results revealed that subepithelial nerve fiber bundles of the anterior, medium and posterior regions of tongue were arise from deep muscular layer of tongue . (bvsalud.org)
  • In psychophysical experiments, we used a selective conduction block of myelinated fibers to test the hypothesis that activity in A-fibers contributes to cowhage-induced itch. (jneurosci.org)
  • In reviewing the literature, 8 of 10 cases of acquired MRNF in children had previous abnormalities of the optic nerve, 4 of 10 had associated bilateral optic nerve head drusen, 3 of 10 had associated optic nerve glioma, and 3 of 10 had a history of significant increased intracranial pressure requiring surgical intervention. (duke.edu)
  • CONCLUSIONS: Although the etiology of acquired MRNF is uncertain, this case plus a review of the literature suggest that it may be related to changes in the lamina cribosa combined with possible optic nerve injury caused by optic nerve head drusen, optic nerve glioma, or increased intracranial pressure and that it can occur months to years after intervention. (duke.edu)
  • Optic nerve head drusen (ONHD) represent the congenital, developmental anomaly of the second cranial nerve. (intechopen.com)
  • Genetically, optic nerve head drusen are inherited in autosomal dominant (AD) type of inheritance with variable penetration. (intechopen.com)
  • If you are a suspect for glaucoma in any way (high pressures, suspicious anatomy, family history) then it would be a good idea to establish a baseline visual field test to map the area of defect associated with your myelinated nerve fiber layer. (eyedolatryblog.com)
  • Visual results in these patients suggest that aggressive amblyopia therapy should be considered in patients with anisometropic amblyopia associated with extensive myelination continuous with the optic nerve. (umn.edu)
  • Magerl, 1991 ) suggest that activity in thinly myelinated Aδ-fibers may contribute to the sensation of itch. (jneurosci.org)
  • Taken together, all these results demonstrated that SilkBridge TM has an optimized balance of biomechanical and biological properties, which allowed proceeding with a first-in-human clinical study aimed at evaluating safety and effectiveness of using the device for the reconstruction of digital nerve defects in humans. (frontiersin.org)
  • In humans, there are on average 30,000 nerve fibers within the cochlear nerve. (wikipedia.org)
  • Electrophysiological experiments in anesthetized monkey were used to investigate the responsiveness of cutaneous, nociceptive, myelinated afferents to different chemical stimuli (cowhage spicules, histamine, capsaicin). (jneurosci.org)
  • An identical pattern was seen in another cutaneous nerve analyzed, the sural nerve. (researchhunt.com)
  • Amount 2 The reduced C:A-fiber proportion in naked mole-rats is fixed to cutaneous nerves generally. (researchhunt.com)
  • A,B: Nude mole-rats possess a considerably lower C:A-fiber proportion in cutaneous saphenous and sural nerves weighed against all other types. (researchhunt.com)
  • The electrophysiological finding of conduction block in the absence of abnormalities in sensory nerves is the hallmark of MMN, but can be difficult to detect. (nature.com)
  • Results show most fibers are unmyelinated, yet recent findings in experimental animals suggest many pulpal afferents originate from fibers that are myelinated at more proximal locations. (biomedcentral.com)
  • In the late 1960s, neurophysiologic testing allowed the classification of CMT into 2 groups, one with slow nerve conduction velocities and histologic features of a hypertrophic demyelinating neuropathy (hereditary motor and sensory neuropathy type 1 or CMT1) and another with relatively normal velocities and axonal and neuronal degeneration (hereditary motor and sensory neuropathy type 2 or CMT2). (medscape.com)
  • Myelination of optic nerve fibers terminate at lamina cribrosa. (maltepe.edu.tr)
  • Amount 1 Naked mole-rats possess a lesser C:A-fiber proportion in saphenous nerves weighed against various other Bathyergidae significantly. (researchhunt.com)
  • Rats in the AE group performed treadmill running for 1 h per day for 2 wk, following which the bilateral tibial nerves of the two groups were removed to examine MF and capillary structure. (elsevier.com)
  • The purpose of this paper was to study the sensory myelinated and unmyelinated nerve fibers found in the subepithelial lamina propria of tongue mucosa of aging rats . (bvsalud.org)
  • induced by chronic constriction injury of the infraorbital nerve in rats. (rochester.edu)
  • Saphenous, sural, common peroneal, tibial, lateral gastrocnemius, and medial gastrocnemius nerves had been dissected from both hip and legs and postfixed in 4% paraformaldehyde/2.5% glutaraldehyde in 0.1 JW-642 M PBS for 3 times (only saphenous and tibial nerves had been extracted from mice). (researchhunt.com)
  • 1987). Right here we also discovered that the C:A-fiber ratios had been lower in the normal peroneal and tibial nerves (Fig. 2C,D) weighed against the saphenous and sural nerves in every species examined (Fig. 2A,B), aside from the nude mole-rat. (researchhunt.com)
  • Many myelinated nerve fibers in white matter degenerate and are lost, leading to some disconnections between various parts of the central nervous system. (bu.edu)
  • What is a collection of nerve cell bodies outside of the central nervous system called? (histology-world.com)
  • The effect of temperature on the sodium and potassium permeability changes in myelinated nerve fibres of Xenopus laevis . (springer.com)
  • Effects of nerve compression or ischaemia on conduction properties of myelinated and non-myelinated nerve fibres. (nih.gov)
  • Compression of the nerve at 200 mmHg blocked the AI component (large myelinated fibres) after about 23 min, while compression at 400 mmHg shortened this time to 11 min. (nih.gov)
  • The A2 component (thinner myelinated fibres) had a lower conduction velocity and a higher resistance to compression. (nih.gov)
  • There was just a slight decrease in conduction velocity of the non-myelinated fibres when the nerves were compressed at 200 mmHg for 2 h. (nih.gov)
  • The thinner myelinated fibres were more susceptible to deprivation of oxygen than the thicker ones, while non-myelinated fibres differed in response according to method of ischaemia induction. (nih.gov)
  • It is concluded that non-myelinated fibres are very resistant to compression and a very high pressure (greater than 400 mmHg) is needed to affect these fibres. (nih.gov)
  • Unilateral extensive myelination of the peripapillary nerve fibers may be associated with anisometropic myopia, strabismus, and reduced vision. (umn.edu)
  • RESULTS: The child developed bilateral MRNF adjacent to the optic nerve 5 months after unilateral ONSF. (duke.edu)
  • However, rigorous psychophysical and neurophysiological evidence for a functional role of A-fibers in the mediation of nonhistaminergic itch in primates is lacking. (jneurosci.org)
  • The SilkBridge TM conduit led to a very good functional and morphological recovery of the median nerve, similar to that observed with the reference autograft nerve reconstruction procedure. (frontiersin.org)
  • Although autologous nerve transplantation remains the preferred strategy for reconstruction, it is limited by donor tissues, the sacrifice of functional nerves, and the potential formation of neuromas [ 4 - 6 ]. (hindawi.com)
  • The newly regenerated nerve fibers were functional and myelinated. (wingsforlife.com)
  • Nerve fibers are grouped into fascicles of variable numbers. (nysora.com)
  • The size, number, and pattern of fascicles vary in different nerves and at different levels along their paths. (nysora.com)
  • Studies show that myelinated nerve fiber layer is very rare ( less than one percent of the population! ). (eyedolatryblog.com)
  • It is unusual but possible to develop myelinated nerve fiber layer changes after birth in cases of ocular tumors or trauma, but this is exceedingly rare and a result of a disruption to the normal ocular tissue. (eyedolatryblog.com)
  • If you have myelinated nerve fiber layer, your doctor will definitely talk to you about this finding (even though it is normal) because it is permanent inside of your eye. (eyedolatryblog.com)
  • The obtained results, could serve as a tool for developing multi-electrode systems that potentially enable fiber-type selective stimulation of nerve fibers. (degruyter.com)
  • We tested the hypothesis that insulin itself influences conduction of myelinated fibers independent of hyperglycemia in experimental diabetes. (nih.gov)
  • depressor f's afferent nerve fibers that when stimulated reflexly cause diminished vasomotor tone and thus decreased arterial pressure. (thefreedictionary.com)
  • The patient had bilateral retinal fiber myelination and greater vision loss in the more hyperopic eye . (bvsalud.org)
  • The paper presents young female patient with bilateral optic nerve drusen and progressive visual field defects (scotomas), which implies topical hypotensive therapy. (intechopen.com)
  • Grewal, S. P.S. / Atrophy of myelinated nerve fibers in pituitary adenoma . (nebraska.edu)
  • The repair of peripheral nerve injury is a very complicated pathological process, and it is difficult to obtain satisfactory results because of slow nerve regeneration, Wallerian degeneration, tissue adhesion, and muscle and motor endplate atrophy. (hindawi.com)
  • We show that the intensity profiles of the major Raman bands vary significantly between the three major regions of myelinated nerve fiber: internode, paranode and the node of Ranvier. (ipmnet.ru)
  • Disappearance of MRNF have also been reported after surgery and insults to the optic nerve. (eyewiki.org)
  • Although some MRNF may appear macroscopically contiguous with the optic disc, one histological study demonstrated that the region of myelination was not contiguous with that of the optic nerve. (eyewiki.org)
  • A detailed review of the current anatomical and electrophysiological literature was performed and tables containing the biophysical properties of the amphibian and mammalian myelinated nerve fibers were compiled. (rice.edu)