Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Flicker Fusion: The point or frequency at which all flicker of an intermittent light stimulus disappears.Nitrazepam: A benzodiazepine derivative used as an anticonvulsant and hypnotic.Word Association Tests: Lists of words to which individuals are asked to respond ascertaining the conceptual meaning held by the individual.Anti-Anxiety Agents: Agents that alleviate ANXIETY, tension, and ANXIETY DISORDERS, promote sedation, and have a calming effect without affecting clarity of consciousness or neurologic conditions. ADRENERGIC BETA-ANTAGONISTS are commonly used in the symptomatic treatment of anxiety but are not included here.Psychomotor Disorders: Abnormalities of motor function that are associated with organic and non-organic cognitive disorders.Azabicyclo Compounds: Bicyclic bridged compounds that contain a nitrogen which has three bonds. The nomenclature indicates the number of atoms in each path around the rings, such as [2.2.2] for three equal length paths. Some members are TROPANES and BETA LACTAMS.Hypnotics and Sedatives: Drugs used to induce drowsiness or sleep or to reduce psychological excitement or anxiety.Lorazepam: A benzodiazepine used as an anti-anxiety agent with few side effects. It also has hypnotic, anticonvulsant, and considerable sedative properties and has been proposed as a preanesthetic agent.Clorazepate Dipotassium: A water-soluble benzodiazepine derivative effective in the treatment of anxiety. It has also muscle relaxant and anticonvulsant actions.Reaction Time: The time from the onset of a stimulus until a response is observed.Triazolam: A short-acting benzodiazepine used in the treatment of insomnia. Some countries temporarily withdrew triazolam from the market because of concerns about adverse reactions, mostly psychological, associated with higher dose ranges. Its use at lower doses with appropriate care and labeling has been reaffirmed by the FDA and most other countries.Laboratories, Dental: Facilities for the performance of services related to dental treatment but not done directly in the patient's mouth.Automobile Driving: The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.Penbutolol: A nonselective beta-blocker used as an antihypertensive and an antianginal agent.Amitriptyline: Tricyclic antidepressant with anticholinergic and sedative properties. It appears to prevent the re-uptake of norepinephrine and serotonin at nerve terminals, thus potentiating the action of these neurotransmitters. Amitriptyline also appears to antagonize cholinergic and alpha-1 adrenergic responses to bioactive amines.Histamine H1 Antagonists: Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Motor Skills: Performance of complex motor acts.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Diazepam: A benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant, and amnesic properties and a long duration of action. Its actions are mediated by enhancement of GAMMA-AMINOBUTYRIC ACID activity.Psychological Tests: Standardized tests designed to measure abilities, as in intelligence, aptitude, and achievement tests, or to evaluate personality traits.Arousal: Cortical vigilance or readiness of tone, presumed to be in response to sensory stimulation via the reticular activating system.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Benzodiazepines: A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.Ethanol: A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.Placebos: Any dummy medication or treatment. Although placebos originally were medicinal preparations having no specific pharmacological activity against a targeted condition, the concept has been extended to include treatments or procedures, especially those administered to control groups in clinical trials in order to provide baseline measurements for the experimental protocol.Affect: The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Task Performance and Analysis: The detailed examination of observable activity or behavior associated with the execution or completion of a required function or unit of work.Athletic Performance: Carrying out of specific physical routines or procedures by one who is trained or skilled in physical activity. Performance is influenced by a combination of physiological, psychological, and socio-cultural factors.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Employee Performance Appraisal: The assessment of the functioning of an employee in relation to work.Animal Feed: Foodstuff used especially for domestic and laboratory animals, or livestock.Cognition Disorders: Disturbances in mental processes related to learning, thinking, reasoning, and judgment.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Random Allocation: A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.Educational Measurement: The assessing of academic or educational achievement. It includes all aspects of testing and test construction.Animal Nutritional Physiological Phenomena: Nutritional physiology of animals.Memory, Short-Term: Remembrance of information for a few seconds to hours.Weight Gain: Increase in BODY WEIGHT over existing weight.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Equipment Design: Methods of creating machines and devices.ROC Curve: A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.Weaning: Permanent deprivation of breast milk and commencement of nourishment with other food. (From Stedman, 25th ed)Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Animal Husbandry: The science of breeding, feeding and care of domestic animals; includes housing and nutrition.Magnetic Resonance Imaging: 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.Clinical Competence: The capability to perform acceptably those duties directly related to patient care.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Discrimination (Psychology): Differential response to different stimuli.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Models, Statistical: Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.Quality Control: A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)Quality Indicators, Health Care: Norms, criteria, standards, and other direct qualitative and quantitative measures used in determining the quality of health care.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Memory Disorders: Disturbances in registering an impression, in the retention of an acquired impression, or in the recall of an impression. Memory impairments are associated with DEMENTIA; CRANIOCEREBRAL TRAUMA; ENCEPHALITIS; ALCOHOLISM (see also ALCOHOL AMNESTIC DISORDER); SCHIZOPHRENIA; and other conditions.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Achievement: Success in bringing an effort to the desired end; the degree or level of success attained in some specified area (esp. scholastic) or in general.Karnofsky Performance Status: A performance measure for rating the ability of a person to perform usual activities, evaluating a patient's progress after a therapeutic procedure, and determining a patient's suitability for therapy. It is used most commonly in the prognosis of cancer therapy, usually after chemotherapy and customarily administered before and after therapy. It was named for Dr. David A. Karnofsky, an American specialist in cancer chemotherapy.Physical Endurance: The time span between the beginning of physical activity by an individual and the termination because of exhaustion.Reagent Kits, Diagnostic: Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use.

*  NIOSHTIC-2 Publications Search - 00202964 - Effects of respirators on performance of physical, psychomotor and cognitive tasks.

The three types of work rates, physical, psychomotor and cognitive, were selected to represent the broadest spe ... was conducted to investigate test procedures which could be used to determine quantitatively any decrement in work performance ... Effects on performance were noted in the physical work task, with increased exertion and in the psychomotor tasks with lessened ... These tests indicated that respirators appeared to have no effect on the performance of certain tasks such as cognitive and ...

*  The Use and Misuse of Sleeping Pills : a Clinical Guide (eBook, 1980) []

Psychomotor Measures of Residual Effects --. Subjective Evaluation of Daytime Performance --. Hypnotics and Driving --. Summary ... Psychomotor Measures of Residual Effects -- Subjective Evaluation of Daytime Performance -- Hypnotics and Driving -- Summary ...

*  The John Sutton Memorial Lecture, 2009. Conductance systems: an integrative approach to the physiology of extreme conditions.

Psychomotor Performance. Regional Blood Flow. Respiratory Mechanics. Chemical. Reg. No./Substance: 124-38-9/Carbon Dioxide; ...

*  Nonvisual learning of intrinsic object properties in a reaching task dissociates grasp from reach.

Psychomotor Performance / physiology*. Touch / physiology. From MEDLINE®/PubMed®, a database of the U.S. National Library of ...

*  Comparison of active motor items in infants born preterm and infants born full term.

Psychomotor Performance / physiology*. Randomized Controlled Trials as Topic. Time Factors. Treatment Outcome. ...

*  Plus it

Perrott DR, Saberi K, Brown K, and Strybel TZ. Auditory psychomotor coordination and visual search performance. Percept ... that visual orientation in the presence of a centrally disparate auditory stimulus was significantly improved and performance ...

*  manual dexterity |

in psychomotor learning: Simple components of bodily skills A number of basic motor abilities underlie the performance of many ...

*  8 | NZ Transport Agency

Level of arousal - excessive arousal may impair performance and judgement. Underarousal (eg the psychomotor retardation of ... 1 psychomotor functioning. 2 behaviour. 3 mood (including suicidal ideation). 4 medication. 5 insight. Same factors to consider ... 8.1.1 Psychomotor and cognitive functioning. Medical practitioners should consider the following factors, if appropriate:. * ...

*  DHP FY15.1 SBIR Solicitation Topics

Develop a simulation-based system to provide psychomotor skills training to advanced health care providers in the performance ... Human performance can then be compared to the model predictions in order to calibrate model performance. The results of this ... Phase II - Performance Parameters: Design of a dosimeter or packaging to provide stability for a minimum of 30 days after ... Phase I - Performance Parameters: Success will be measured by the number of classes of compounds (described above) that were ...

*  Tiocolchicósido - Wikipedia

Assessment of efficacy and psychomotor performances of thiocolchicoside and tizanidine in patients with acute low back pain». ...ósido

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The experimental data show that participants adjust their grasping behavior to compensate for target location uncertainty introduced by errors both in visual and eye position sensing (CTU). These results suggest that the brain represents CTU and incorporates its effects on estimates of target location. Previous studies have shown that the brain represents the reliability of sensory data both within (Landy et al. 1995; Saunders and Knill 2004) and between modalities (Atkins et al. 2001; Battaglia et al. 2003; Ernst and Banks 2002), in addition to representing the endpoint variance of motor movements (Harris and Wolpert 1998; Trommershauser et al. 2003, 2005). By representing CTU, the brain has all the components required to predict performance of complex sensorimotor behaviors involving perception-action cycles.. Although we attribute the change in grasping behavior in the occluded condition to target uncertainty, it may be that holding eye position away from forward view creates an ...

*  S&W Performance Model 66-4 .357 3'

Good evening all! I am new to this forum and this is my first post, which is actually a question. I have a S&W Performance Model 66-4 .357 with a 3' barrel which is considered more rare or un

Flicker (screen): Flicker is a visible fading between cycles displayed on video displays, especially the refresh interval on cathode ray tube (CRT) based computer screens. Flicker occurs on CRTs when they are driven at a low refresh rate, allowing the brightness to drop for time intervals sufficiently long to be noticed by a human eye – see persistence of vision and flicker fusion threshold.NitrazepamWhately Carington: Walter Whately Carington (1892–1947) was a British parapsychologist. His name, originally Walter Whately Smith, was changed in 1933.Anxiolytic: An anxiolytic (also antipanic or antianxiety agent) is a medication or other intervention that inhibits anxiety. This effect is in contrast to anxiogenic agents, which increase anxiety.EszopicloneNonbenzodiazepine: Nonbenzodiazepines (sometimes referred to colloquially as "Z-drugs") are a class of psychoactive drugs that are very benzodiazepine-like in nature. Nonbenzodiazepines pharmacodynamics are almost entirely the same as benzodiazepine drugs and therefore employ similar benefits, side-effects, and risks.LorazepamDipotassium guanylateTriazolamTema Motorway: The Tema Motorway is a highway that links Tema to Accra—capital of Ghana. It was the only motorway in Ghana.CyclobenzaprinePlacebo-controlled study: Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment.Adult interaction with infants: When adults come into contact with infants, it is unlikely that they would be able to have a proper conversation, as the infant would not know enough about pop culture or general knowledge to create a stimulating conversation for the adult. Also, the adult may not understand baby-language and cannot relate to their situation properly.Non-rapid eye movement sleepLow arousal theory: Low arousal}}Cognitive skill: Cognitive functioning is a term referring to a human’s ability to process to (thoughts) that should not deplete on a large scale in healthy individuals. Cognition mainly refers to things like memory, the ability to learn new information, speech, understanding of written material.Explicit memory: Explicit memory is the conscious, intentional recollection of previous experiences and information. People use explicit memory throughout the day, such as remembering the time of an appointment or recollecting an event from years ago.Benzodiazepine misuse: The non-medical use of Benzodiazepine drugs (called misuse or abuse in public health journals) is the use of benzodiazepines without a prescription, often for recreational purposes, which poses risks of dependence, withdrawal and other long-term effects. Benzodiazepines are one of the more common prescription drugs used recreationally.Ethanol fuel: Ethanol fuel is ethanol (ethyl alcohol), the same type of alcohol found in alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline.Gary H. Posner: Gary H. Posner (born c.Repeatable Battery for the Assessment of Neuropsychological Status: The Repeatable Battery for the Assessment of Neuropsychological Status is a neuropsychological assessment initially introduced in 1998. It consists of ten subtests which give five scores, one for each of the five domains tested (immediate memory, visuospatial/constructional, language, attention, delayed memory).Drug interaction: A drug interaction is a situation in which a substance (usually another drug) affects the activity of a drug when both are administered together. This action can be synergistic (when the drug's effect is increased) or antagonistic (when the drug's effect is decreased) or a new effect can be produced that neither produces on its own.Temporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingDan BuckinghamGeneralizability theory: Generalizability theory, or G Theory, is a statistical framework for conceptualizing, investigating, and designing reliable observations. It is used to determine the reliability (i.Assay sensitivity: Assay sensitivity is a property of a clinical trial defined as the ability of a trial to distinguish an effective treatment from a less effective or ineffective intervention. Without assay sensitivity, a trial is not internally valid and is not capable of comparing the efficacy of two interventions.Clonal Selection Algorithm: In artificial immune systems, Clonal selection algorithms are a class of algorithms inspired by the clonal selection theory of acquired immunity that explains how B and T lymphocytes improve their response to antigens over time called affinity maturation. These algorithms focus on the Darwinian attributes of the theory where selection is inspired by the affinity of antigen-antibody interactions, reproduction is inspired by cell division, and variation is inspired by somatic hypermutation.Dry matter: The dry matter (or otherwise known as dry weight) is a measurement of the mass of something when completely dried.Postoperative cognitive dysfunction: Postoperative cognitive dysfunction (POCD) is a short-term decline in cognitive function (especially in memory and executive functions) that may last from a few days to a few weeks after surgery. In rare cases, this disorder may persist for several months after major surgery.High-performance liquid chromatography: High-performance liquid chromatography (HPLC; formerly referred to as high-pressure liquid chromatography), is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pass a pressurized liquid solvent containing the sample mixture through a column filled with a solid adsorbent material.Interval boundary element method: Interval boundary element method is classical boundary element method with the interval parameters.
Beta encoder: A beta encoder is an analog to digital conversion (A/D) system in which a real number in the unit interval is represented by a finite representation of a sequence in base beta, with beta being a real number between 1 and 2. Beta encoders are an alternative to traditional approaches to pulse code modulation.Subtherapeutic antibiotic use in swine: Antibiotics are commonly used in commercial swine production in the United States and around the world. They are used for disease treatment, disease prevention and control, and growth promotion.College of Veterinary Science and Animal Husbandry, Anand: The College of Veterinary Science and Animal Husbandry, Anand was founded in 1964. It is a part of AAU, Anand, Gujarat, India.HyperintensityInverse probability weighting: Inverse probability weighting is a statistical technique for calculating statistics standardized to a population different from that in which the data was collected. Study designs with a disparate sampling population and population of target inference (target population) are common in application.Analytical quality control: Analytical quality control, commonly shortened to AQC refers to all those processes and procedures designed to ensure that the results of laboratory analysis are consistent, comparable, accurate and within specified limits of precision.analytical quality control (AQC) program to ensure the highest level of confidence in reported data Constituents submitted to the analytical laboratory must be accurately described to avoid faulty interpretations, approximations, or incorrect results.Beef cattle: Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk production). The meat of adult cattle is known as beef.Memory clinic: A memory clinic is a dedicated medical clinic specialising in the assessment and diagnosis of memory disorders. Memory clinics were first seen in the UK in the 1980s, mainly in academic research centres.Physical strength: Strength (physics)}}Bioline Reagents: Bioline Reagents is a primary manufacturer and developerBioline: The PCR Company | Company Profile of a wide range of specialised molecular biology products for the life science industry and research markets. It manufactures reagents including ultra-pure nucleotides, DNA polymerases and mixes, DNA markers, competent cells, products for RNA analysis and other general reagents for molecular biology.

(1/9774) Signal-, set- and movement-related activity in the human brain: an event-related fMRI study.

Electrophysiological studies on monkeys have been able to distinguish sensory and motor signals close in time by pseudorandomly delaying the cue that instructs the movement from the stimulus that triggers the movement. We have used a similar experimental design in functional magnetic resonance imaging (fMRI), scanning subjects while they performed a visuomotor conditional task with instructed delays. One of four shapes was presented briefly. Two shapes instructed the subjects to flex the index finger; the other two shapes coded the flexion of the middle finger. The subjects were told to perform the movement after a tone. We have exploited a novel use of event-related fMRI. By systematically varying the interval between the visual and acoustic stimuli, it has been possible to estimate the significance of the evoked haemodynamic response (EHR) to each of the stimuli, despite their temporal proximity in relation to the time constant of the EHR. Furthermore, by varying the phase between events and image acquisition, we have been able to achieve high temporal resolution while scanning the whole brain. We dissociated sensory and motor components of the sensorimotor transformations elicited by the task, and assessed sustained activity during the instructed delays. In calcarine and occipitotemporal cortex, the responses were exclusively associated with the visual instruction cues. In temporal auditory cortex and in primary motor cortex, they were exclusively associated with the auditory trigger stimulus. In ventral prefrontal cortex there were movement-related responses preceded by preparatory activity and by signal-related activity. Finally, responses associated with the instruction cue and with sustained activity during the delay period were observed in the dorsal premotor cortex and in the dorsal posterior parietal cortex. Where the association between a visual cue and the appropriate movement is arbitrary, the underlying visuomotor transformations are not achieved exclusively through frontoparietal interactions. Rather, these processes seem to rely on the ventral visual stream, the ventral prefrontal cortex and the anterior part of the dorsal premotor cortex.  (+info)

(2/9774) Cerebellar Purkinje cell simple spike discharge encodes movement velocity in primates during visuomotor arm tracking.

Pathophysiological, lesion, and electrophysiological studies suggest that the cerebellar cortex is important for controlling the direction and speed of movement. The relationship of cerebellar Purkinje cell discharge to the control of arm movement parameters, however, remains unclear. The goal of this study was to examine how movement direction and speed and their interaction-velocity-modulate Purkinje cell simple spike discharge in an arm movement task in which direction and speed were independently controlled. The simple spike discharge of 154 Purkinje cells was recorded in two monkeys during the performance of two visuomotor tasks that required the animals to track targets that moved in one of eight directions and at one of four speeds. Single-parameter regression analyses revealed that a large proportion of cells had discharge modulation related to movement direction and speed. Most cells with significant directional tuning, however, were modulated at one speed, and most cells with speed-related discharge were modulated along one direction; this suggested that the patterns of simple spike discharge were not adequately described by single-parameter models. Therefore, a regression surface was fitted to the data, which showed that the discharge could be tuned to specific direction-speed combinations (preferred velocities). The overall variability in simple spike discharge was well described by the surface model, and the velocities corresponding to maximal and minimal discharge rates were distributed uniformly throughout the workspace. Simple spike discharge therefore appears to integrate information about both the direction and speed of arm movements, thereby encoding movement velocity.  (+info)

(3/9774) Complete compensation in skilled reaching success with associated impairments in limb synergies, after dorsal column lesion in the rat.

Each of the dorsal columns of the rat spinal cord conveys primary sensory information, by way of the medullary dorsal column nucleus, to the ventrobasal thalamus on the contralateral side; thus the dorsal columns are an important source of neural input to the sensorimotor cortex. Damage to the dorsal columns causes impairments in synergistic proximal or whole-body movements in cats and distal limb impairments in primates, particularly in multiarticulated finger movements and tactile foviation while handling objects, but the behavioral effects of afferent fiber lesions in the dorsal columns of rodents have not been described. Female Long-Evans rats were trained to reach with a forelimb for food pellets and subsequently received lesions of the dorsomedial spinal cord at the C2 level, ipsilateral to their preferred limb. Reaching success completely recovered within a few days of dorsal column lesion. Nevertheless, a detailed analysis of high-speed video recordings revealed that rotatory limb movements (aiming, pronation, supination, etc.) were irreversibly impaired. Compensation was achieved with whole-body and alternate limb movements. These results indicate the following: (1) in the absence of the dorsal columns, other sensorimotor pathways support endpoint success in reaching; (2) sensory input conveyed by the dorsal columns is important for both proximal and distal limb movements used for skilled reaching; and (3) detailed behavioral analyses in addition to endpoint measures are necessary to completely describe the effects of dorsal column lesions.  (+info)

(4/9774) Behavioral, toxic, and neurochemical effects of sydnocarb, a novel psychomotor stimulant: comparisons with methamphetamine.

Sydnocarb (3-(beta-phenylisopropyl)-N-phenylcarbamoylsydnonimine) is a psychostimulant in clinical practice in Russia as a primary and adjunct therapy for a host of psychiatric disorders, including schizophrenia and depression. It has been described as a stimulant with an addiction liability and toxicity less than that of amphetamines. The present study undertook to evaluate the psychomotor stimulant effects of sydnocarb in comparison to those of methamphetamine. Sydnocarb increased locomotor activity of mice with reduced potency (approximately 10-fold) and efficacy compared with methamphetamine. Sydnocarb blocked the locomotor depressant effects of haloperidol at doses that were inactive when given alone. The locomotor stimulant effects of both methamphetamine and sydnocarb were dose-dependently blocked by the dopamine D1 and D2 antagonists SCH 39166 and spiperone, respectively; blockade generally occurred at doses of the antagonists that did not depress locomotor activity when given alone. In mice trained to discriminate methamphetamine from saline, sydnocarb fully substituted for methamphetamine with a 9-fold lower potency. When substituted for methamphetamine under self-administration experiments in rats, 10-fold higher concentrations of sydnocarb maintained responding by its i.v. presentation. Sydnocarb engendered stereotypy in high doses with approximately a 2-fold lower potency than methamphetamine. However, sydnocarb was much less efficacious than methamphetamine in inducing stereotyped behavior. Both sydnocarb and methamphetamine increased dialysate levels of dopamine in mouse striatum; however, the potency and efficacy of sydnocarb was less than methamphetamine. The convulsive effects of cocaine were significantly enhanced by the coadministration of nontoxic doses of methamphetamine but not of sydnocarb. Taken together, the present findings indicate that sydnocarb has psychomotor stimulant effects that are shared by methamphetamine while demonstrating a reduced behavioral toxicity.  (+info)

(5/9774) Evidence for an eye-centered spherical representation of the visuomotor map.

During visually guided movement, visual coordinates of target location must be transformed into coordinates appropriate for movement. To investigate the representation of this visuomotor coordinate transformation, we examined changes in pointing behavior induced by a local visuomotor remapping. The visual feedback of finger position was limited to one location within the workspace, at which a discrepancy was introduced between the actual and visually perceived finger position. This remapping induced a change in pointing that extended over the entire workspace and was best captured by a spherical coordinate system centered near the eyes.  (+info)

(6/9774) Visuomotor processing as reflected in the directional discharge of premotor and primary motor cortex neurons.

Premotor and primary motor cortical neuronal firing was studied in two monkeys during an instructed delay, pursuit tracking task. The task included a premovement "cue period," during which the target was presented at the periphery of the workspace and moved to the center of the workspace along one of eight directions at one of four constant speeds. The "track period" consisted of a visually guided, error-constrained arm movement during which the animal tracked the target as it moved from the central start box along a line to the opposite periphery of the workspace. Behaviorally, the animals tracked the required directions and speeds with highly constrained trajectories. The eye movements consisted of saccades to the target at the onset of the cue period, followed by smooth pursuit intermingled with saccades throughout the cue and track periods. Initially, an analysis of variance (ANOVA) was used to test for direction and period effects in the firing. Subsequently, a linear regression analysis was used to fit the average firing from the cue and track periods to a cosine model. Directional tuning as determined by a significant fit to the cosine model was a prominent feature of the discharge during both the cue and track periods. However, the directional tuning of the firing of a single cell was not always constant across the cue and track periods. Approximately one-half of the neurons had differences in their preferred directions (PDs) of >45 degrees between cue and track periods. The PD in the cue or track period was not dependent on the target speed. A second linear regression analysis based on calculation of the preferred direction in 20-ms bins (i.e., the PD trajectory) was used to examine on a finer time scale the temporal evolution of this change in directional tuning. The PD trajectories in the cue period were not straight but instead rotated over the workspace to align with the track period PD. Both clockwise and counterclockwise rotations occurred. The PD trajectories were relatively straight during most of the track period. The rotation and eventual convergence of the PD trajectories in the cue period to the preferred direction of the track period may reflect the transformation of visual information into motor commands. The widely dispersed PD trajectories in the cue period would allow targets to be detected over a wide spatial aperture. The convergence of the PD trajectories occurring at the cue-track transition may serve as a "Go" signal to move that was not explicitly supplied by the paradigm. Furthermore, the rotation and convergence of the PD trajectories may provide a mechanism for nonstandard mapping. Standard mapping refers to a sensorimotor transformation in which the stimulus is the object of the reach. Nonstandard mapping is the mapping of an arbitrary stimulus into an arbitrary movement. The shifts in the PD may allow relevant visual information from any direction to be transformed into an appropriate movement direction, providing a neural substrate for nonstandard stimulus-response mappings.  (+info)

(7/9774) Visual control of locomotion in Parkinson's disease.

The effect of placing parallel lines on the walking surface on parkinsonian gait was evaluated. To identify the kind of visual cues (static or dynamic) required for the control of locomotion, we tested two visual conditions: normal lighting and stroboscopic illumination (three flashes/s), the latter acting to suppress dynamic visual cues completely. Sixteen subjects with idiopathic Parkinson's disease (nine males, seven females; mean age 68.8 years) and the same number of age-matched controls (seven males; nine females, mean age 67.5 years) were studied. During the baseline phase, Parkinson's disease patients walked with a short-stepped, slow velocity pattern. The double limb support duration was increased and the step cadence was reduced relative to normal. Under normal lighting, visual cues from the lines on the walking surface induced a significant improvement in gait velocity and stride length in Parkinson's disease patients. With stroboscopic illumination and without lines, both groups reduced their stride length and velocity but the changes were significant only in the Parkinson's disease group, indicating greater dependence on dynamic visual information. When stroboscopic light was used with stripes on the floor, the improvement in gait due to the stripes was suppressed in parkinsonian patients. These results demonstrate that the perceived motion of stripes, induced by the patient's walking, is essential to improve the gait parameters and thus favour the hypothesis of a specific visual-motor pathway which is particularly responsive to rapidly moving targets. Previous studies have proposed a cerebellar circuit, allowing the visual stimuli to by-pass the damaged basal ganglia.  (+info)

(8/9774) Common 3 and 10 Hz oscillations modulate human eye and finger movements while they simultaneously track a visual target.

1. A 10 Hz range centrally originating oscillation has been found to modulate slow finger movements and anticipatory smooth eye movements. To determine if an interaction or linkage occurs between these two central oscillations during combined visuo-manual tracking, frequency and coherence analysis were performed on finger and eye movements while they simultaneously tracked a visual target moving in intermittently visible sinusoidal patterns. 2. Two different frequencies of common or linked oscillation were found. The first, at 2-3 Hz, was dependent on visual feedback of target and finger tracking positions. The second, at around 10 Hz, still occurred when both target and finger positions were largely obscured, indicating that this common oscillation was generated internally by the motor system independent of visual feedback. Both 3 and 10 Hz oscillation frequencies were also shared by the right and left fingers if subjects used these together to track a visual target. 3. The linking of the 10 Hz range oscillations between the eyes and finger was task specific; it never occurred when eye and finger movements were made simultaneously and independently, but only when they moved simultaneously and followed the target together. However, although specific for tracking by the eyes and fingers together, the linking behaviour did not appear to be a prerequisite for such tracking, since significant coherence in the 10 Hz range was only present in a proportion of trials where these combined movements were made. 4. The experiments show that common oscillations may modulate anatomically very distinct structures, indicating that single central oscillations may have a widespread distribution in the central nervous system. The task-specific manifestation of the common oscillation in the eye and finger suggests that such mechanisms may have a functional role in hand-eye co-ordination.  (+info)


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