A subtype of epilepsy characterized by seizures that are consistently provoked by a certain specific stimulus. Auditory, visual, and somatosensory stimuli as well as the acts of writing, reading, eating, and decision making are examples of events or activities that may induce seizure activity in affected individuals. (From Neurol Clin 1994 Feb;12(1):57-8)
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
A disorder characterized by the onset of myoclonus in adolescence, a marked increase in the incidence of absence seizures (see EPILEPSY, ABSENCE), and generalized major motor seizures (see EPILEPSY, TONIC-CLONIC). The myoclonic episodes tend to occur shortly after awakening. Seizures tend to be aggravated by sleep deprivation and alcohol consumption. Hereditary and sporadic forms have been identified. (From Adams et al., Principles of Neurology, 6th ed, p323)
Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.
Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASES; (e.g., EPILEPSY, MYOCLONIC). Nocturnal myoclonus is the principal feature of the NOCTURNAL MYOCLONUS SYNDROME. (From Adams et al., Principles of Neurology, 6th ed, pp102-3).
An ovoid densely packed collection of small cells of the anterior hypothalamus lying close to the midline in a shallow impression of the OPTIC CHIASM.
Posterior portion of the CEREBRAL HEMISPHERES responsible for processing visual sensory information. It is located posterior to the parieto-occipital sulcus and extends to the preoccipital notch.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)
Use of electric potential or currents to elicit biological responses.
Application of electric current in treatment without the generation of perceptible heat. It includes electric stimulation of nerves or muscles, passage of current into the body, or use of interrupted current of low intensity to raise the threshold of the skin to pain.
The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.
Act of eliciting a response from a person or organism through physical contact.
A technique that involves the use of electrical coils on the head to generate a brief magnetic field which reaches the CEREBRAL CORTEX. It is coupled with ELECTROMYOGRAPHY response detection to assess cortical excitability by the threshold required to induce MOTOR EVOKED POTENTIALS. This method is also used for BRAIN MAPPING, to study NEUROPHYSIOLOGY, and as a substitute for ELECTROCONVULSIVE THERAPY for treating DEPRESSION. Induction of SEIZURES limits its clinical usage.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The use of specifically placed small electrodes to deliver electrical impulses across the SKIN to relieve PAIN. It is used less frequently to produce ANESTHESIA.
Elements of limited time intervals, contributing to particular results or situations.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Established cell cultures that have the potential to propagate indefinitely.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
Use of sound to elicit a response in the nervous system.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The rate dynamics in chemical or physical systems.
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
Area of the FRONTAL LOBE concerned with primary motor control located in the dorsal PRECENTRAL GYRUS immediately anterior to the central sulcus. It is comprised of three areas: the primary motor cortex located on the anterior paracentral lobule on the medial surface of the brain; the premotor cortex located anterior to the primary motor cortex; and the supplementary motor area located on the midline surface of the hemisphere anterior to the primary motor cortex.
Lens-shaped structure on the inner aspect of the INTERNAL CAPSULE. The SUBTHALAMIC NUCLEUS and pathways traversing this region are concerned with the integration of somatic motor function.
Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
The function of opposing or restraining the excitation of neurons or their target excitable cells.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
Stimulation of the brain, which is self-administered. The stimulation may result in negative or positive reinforcement.

Competitive mechanisms subserve attention in macaque areas V2 and V4. (1/15800)

It is well established that attention modulates visual processing in extrastriate cortex. However, the underlying neural mechanisms are unknown. A consistent observation is that attention has its greatest impact on neuronal responses when multiple stimuli appear together within a cell's receptive field. One way to explain this is to assume that multiple stimuli activate competing populations of neurons and that attention biases this competition in favor of the attended stimulus. In the absence of competing stimuli, there is no competition to be resolved. Accordingly, attention has a more limited effect on the neuronal response to a single stimulus. To test this interpretation, we measured the responses of neurons in macaque areas V2 and V4 using a behavioral paradigm that allowed us to isolate automatic sensory processing mechanisms from attentional effects. First, we measured each cell's response to a single stimulus presented alone inside the receptive field or paired with a second receptive field stimulus, while the monkey attended to a location outside the receptive field. Adding the second stimulus typically caused the neuron's response to move toward the response that was elicited by the second stimulus alone. Then, we directed the monkey's attention to one element of the pair. This drove the neuron's response toward the response elicited when the attended stimulus appeared alone. These findings are consistent with the idea that attention biases competitive interactions among neurons, causing them to respond primarily to the attended stimulus. A quantitative neural model of attention is proposed to account for these results.  (+info)

The neuronal basis of a sensory analyser, the acridid movement detector system. I. Effects of simple incremental and decremental stimuli in light and dark adapted animals. (2/15800)

1. The response of the movement detector (MD) system to proportionally constant incremental and decremental stimuli has been studied at various degrees of light and dark adaptation. Action potentials in the descending contralateral movement detector neurone were taken as the indicator of response. 2. Over a range of at least six log10 units of adapting luminance, the MD system behaves as an ON/OFF unit, giving responses to both incremental and decremental changes in the illumination of a 5 degrees target. 3. With increasing amplitudes of stimuli, both the ON and OFF responses saturate rapidly. Saturation is reached sooner at higher levels of light adaptation. At all levels of light adaptation, the OFF response is greater than the ON. The ratio for saturating stimuli is approximately constant at around 3:2. 4. At the brightest adapting luminances used (20 000 cd/m2) the ON response is reduced but not lost. At the lowest (0-004 cd/m2) the OFF response to a 5 degrees disc fails, but can be regained by increasing the test area to 10 degrees. 5. From what is known of the retina of locusts and other insects, it is thought that light and dark adaptation in the MD system can be adequately explained by events at the retinula cell.  (+info)

MST neuronal responses to heading direction during pursuit eye movements. (3/15800)

As you move through the environment, you see a radial pattern of visual motion with a focus of expansion (FOE) that indicates your heading direction. When self-movement is combined with smooth pursuit eye movements, the turning of the eye distorts the retinal image of the FOE but somehow you still can perceive heading. We studied neurons in the medial superior temporal area (MST) of monkey visual cortex, recording responses to FOE stimuli presented during fixation and smooth pursuit eye movements. Almost all neurons showed significant changes in their FOE selective responses during pursuit eye movements. However, the vector average of all the neuronal responses indicated the direction of the FOE during both fixation and pursuit. Furthermore, the amplitude of the net vector increased with increasing FOE eccentricity. We conclude that neuronal population encoding in MST might contribute to pursuit-tolerant heading perception.  (+info)

Eye movement deficits following ibotenic acid lesions of the nucleus prepositus hypoglossi in monkeys II. Pursuit, vestibular, and optokinetic responses. (4/15800)

The eyes are moved by a combination of neural commands that code eye velocity and eye position. The eye position signal is supposed to be derived from velocity-coded command signals by mathematical integration via a single oculomotor neural integrator. For horizontal eye movements, the neural integrator is thought to reside in the rostral nucleus prepositus hypoglossi (nph) and project directly to the abducens nuclei. In a previous study, permanent, serial ibotenic acid lesions of the nph in three rhesus macaques compromised the neural integrator for fixation but saccades were not affected. In the present study, to determine further whether the nph is the neural substrate for a single oculomotor neural integrator, the effects of those lesions on smooth pursuit, the vestibulo-ocular reflex (VOR), vestibular nystagmus (VN), and optokinetic nystagmus (OKN) are documented. The lesions were correlated with long-lasting deficits in eye movements, indicated most clearly by the animals' inability to maintain steady gaze in the dark. However, smooth pursuit and sinusoidal VOR in the dark, like the saccades in the previous study, were affected minimally. The gain of horizontal smooth pursuit (eye movement/target movement) decreased slightly (<25%) and phase lead increased slightly for all frequencies (0.3-1.0 Hz, +/-10 degrees target tracking), most noticeably for higher frequencies (0.8-0.7 and approximately 20 degrees for 1.0-Hz tracking). Vertical smooth pursuit was not affected significantly. Surprisingly, horizontal sinusoidal VOR gain and phase also were not affected significantly. Lesions had complex effects on both VN and OKN. The plateau of per- and postrotatory VN was shortened substantially ( approximately 50%), whereas the initial response and the time constant of decay decreased slightly. The initial OKN response also decreased slightly, and the charging phase was prolonged transiently then recovered to below normal levels like the VN time constant. Maximum steady-state, slow eye velocity of OKN decreased progressively by approximately 30% over the course of the lesions. These results support the previous conclusion that the oculomotor neural integrator is not a single neural entity and that the mathematical integrative function for different oculomotor subsystems is most likely distributed among a number of nuclei. They also show that the nph apparently is not involved in integrating smooth pursuit signals and that lesions of the nph can fractionate the VOR and nystagmic responses to adequate stimuli.  (+info)

Light-induced calcium influx into retinal axons is regulated by presynaptic nicotinic acetylcholine receptor activity in vivo. (5/15800)

Visual activity is thought to be a critical factor in controlling the development of central retinal projections. Neuronal activity increases cytosolic calcium, which was hypothesized to regulate process outgrowth in neurons. We performed an in vivo imaging study in the retinotectal system of albino Xenopus laevis tadpoles with the fluorescent calcium indicator calcium green 1 dextran (CaGD) to test the role of calcium in regulating axon arbor development. We find that visual stimulus to the retina increased CaGD fluorescence intensity in retinal ganglion cell (RGC) axon arbors within the optic tectum and that branch additions to retinotectal axon arbors correlated with a local rise in calcium in the parent branch. We find three types of responses to visual stimulus, which roughly correlate with the ON, OFF, and SUSTAINED response types of RGC reported by physiological criteria. Imaging in bandscan mode indicated that patterns of calcium transients were nonuniform throughout the axons. We tested whether the increase in calcium in the retinotectal axons required synaptic activity in the retina; intraocular application of tetrodotoxin (10 microM) or nifedipine (1 and 10 microM) blocked the stimulus-induced increase in RGC axonal fluorescence. A second series of pharmacological investigations was designed to determine the mechanism of the calcium elevation in the axon terminals within the optic tectum. Injection of bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid-AM (BAPTA-AM) (20 mM) into the tectal ventricle reduced axonal calcium levels, supporting the idea that visual stimulation increases axonal calcium. Injection of BAPTA (20 mM) into the tectal ventricle to chelate extracellular calcium also attenuated the calcium response to visual stimulation, indicating that calcium enters the axon from the extracellular medium. Caffeine (10 mM) caused a large increase in axonal calcium, indicating that intracellular stores contribute to the calcium signal. Presynaptic nicotinic acetylcholine receptors (nAChRs) may play a role in axon arbor development and the formation of the topographic retinotectal projection. Injection of nicotine (10 microM) into the tectal ventricle significantly elevated RGC axonal calcium levels, whereas application of the nAChR antagonist alphaBTX (100 nM) reduced the stimulus-evoked rise in RGC calcium fluorescence. These data suggest that light stimulus to the retina increases calcium in the axon terminal arbors through a mechanism that includes influx through nAChRs and amplification by calcium-induced calcium release from intracellular calcium stores. Such a mechanism may contribute to developmental plasticity of the retinotectal system by influencing both axon arbor elaboration and the strength of synaptic transmission.  (+info)

Correlated firing in rabbit retinal ganglion cells. (6/15800)

A ganglion cell's receptive field is defined as that region on the retinal surface in which a light stimulus will produce a response. While neighboring ganglion cells may respond to the same stimulus in a region where their receptive fields overlap, it generally has been assumed that each cell makes an independent decision about whether to fire. Recent recordings from cat and salamander retina using multiple electrodes have challenged this view of independent firing by showing that neighboring ganglion cells have an increased tendency to fire together within +/-5 ms. However, there is still uncertainty about which types of ganglion cells fire together, the mechanisms that produce coordinated spikes, and the overall function of coordinated firing. To address these issues, the responses of up to 80 rabbit retinal ganglion cells were recorded simultaneously using a multielectrode array. Of the 11 classes of rabbit ganglion cells previously identified, coordinated firing was observed in five. Plots of the spike train cross-correlation function suggested that coordinated firing occurred through two mechanisms. In the first mechanism, a spike in an interneuron diverged to produce simultaneous spikes in two ganglion cells. This mechanism predominated in four of the five classes including the ON brisk transient cells. In the second mechanism, ganglion cells appeared to activate each other reciprocally. This was the predominant pattern of correlated firing in OFF brisk transient cells. By comparing the receptive field profiles of ON and OFF brisk transient cells, a peripheral extension of the OFF brisk transient cell receptive field was identified that might be produced by lateral spike spread. Thus an individual OFF brisk transient cell can respond both to a light stimulus directed at the center of its receptive field and to stimuli that activate neighboring OFF brisk transient cells through their receptive field centers.  (+info)

Evidence for an eye-centered spherical representation of the visuomotor map. (7/15800)

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)

Visuomotor processing as reflected in the directional discharge of premotor and primary motor cortex neurons. (8/15800)

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)

The perception of speed is influenced by visual contrast. In primary visual cortex (V1), an early stage in the visual perception pathway, the neural tuning to speed is directly related to the neural tuning to temporal frequency of stimulus changes. The influence of contrast on speed perception can be caused by the joint dependency of neural responses in V1 on temporal frequency and contrast. Here, we investigated how tuning to contrast and temporal frequency in V1 of anesthetized mice are related. We found that temporal frequency tuning is contrast-dependent. V1 was more responsive at lower temporal frequencies than the dLGN, consistent with previous work at high contrast. The temporal frequency tuning moves toward higher temporal frequencies with increasing contrast. The low half-maximum temporal frequency does not change with contrast. The Heeger divisive normalization equation provides a good fit to many response characteristics in V1, but does not fit the dependency of temporal frequency and
ABCO Automation signed a value-added reseller agreement with Visual Components, a company specializing in 3-D manufacturing factory simulation software. With this partnership, ABCO adds Visual Components simulation software to its service offerings.. As part of our concepting and designing process, we use Visual Components to provide clients a digital 3D model of their potential system, says Jack Walsh, executive vice president, ABCO Automation. Visual Components is key to helping our clients visualize the design and layout configuration as well as simulate the designs functionality.. The Visual Components software allows user to simulate the design of factory layouts; users get an approximate graphical view of a factory or production line, while the simulation function creates an accurate version of the factory or production line. With the visualization, users can test the simulation and find flaws before finalizing the design. ...
Over successive stages, the visual system develops neurons that respond with view, size and position invariance to objects or faces. A number of computational models have been developed to explain how transform-invariant cells could develop in the visual system. However, a major limitation of computer modelling studies to date has been that the visual stimuli are typically presented one at a time to the network during training. In this paper, we investigate how vision models may self-organize when multiple stimuli are presented together within each visual image during training. We show that as the number of independent stimuli grows large enough, standard competitive neural networks can suddenly switch from learning representations of the multi-stimulus input patterns to representing the individual stimuli. Furthermore, the competitive networks can learn transform (e.g. position or view) invariant representations of the individual stimuli if the network is presented with input patterns containing
Short presentation of a large moving pattern elicits an Ocular Following Response (OFR) that exhibits many of the properties attributed to low-level motion processing such as spatial and temporal integration, contrast gain control and divisive interaction between competing motions. Similar mechanisms have been demonstrated in V1 cortical activity in response to center-surround gratings patterns measured with real-time optical imaging in awake monkeys. More recent experiments of OFR have used disk gratings and bipartite stimuli which are optimized to study the dynamics of center-surround integration. We quantified two main characteristics of the global spatial integration of motion from an intermediate map of possible local translation velocities: (i) a finite optimal stimulus size for driving OFR, surrounded by an antagonistic modulation and (ii) a direction selective suppressive effect of the surround on the contrast gain control of the central stimuli [Barthelemy06,Barthelemy07].In fact, the ...
A computer-implemented image processing method and apparatus for warping a plurality of gel electrophoresis images is provided. The method includes the steps of assigning tiepoints in a reference image and in one or more object images. The tiepoints in the object image are evaluated one-by-one by comparison to regions about a corresponding tiepoint in the reference image, and the location of the tiepoint in the object image is adjusted by slight movement to a location with respect to recognizable features in both the reference and object image thereby defining a tiepoint pair linking a location in the reference image with a location in the object image. outlier tiepoint pairs may be rejected if that pair does not meet predetermined conditions. Warping functions are generated and then globally optimized. The plurality of images are tied together using the tiepoint pairs such that all of the images may be subsequently warped into registration to a single base image selected from the plurality of
It is almost one hundred years since Titchener [E.B. Titchener, Lectures on the Elementary Psychology of Feeling and Attention, Macmillan, New York, 1908] published his influential claim that attending to a particular sensory modality (or location) can speed up the relative time of arrival of stimuli presented in that modality (or location). However, the evidence supporting the existence of prior entry is, to date, mixed. In the present study, we used an audiovisual simultaneity judgment task in an attempt to circumvent the potential methodological confounds inherent in previous research in this area. Participants made simultaneous versus successive judgment responses regarding pairs of auditory and visual stimuli at varying stimulus onset asynchronies (SOAs) using the method of constant stimuli. In different blocks of trials, the participants were instructed to attend either to the auditory or to the visual modality, or else to divide their attention equally between the two modalities. The probability
We present a constant-round protocol for general secure multiparty computation which makes a {\em black-box} use of a pseudorandom generator. In particular, the protocol does not require expensive zero-knowledge proofs and its communication complexity does not depend on the computational complexity of the underlying cryptographic primitive. Our protocol withstands an active, adaptive adversary corrupting a minority of the parties. Previous constant-round protocols of this type were only known in the semi-honest model or for restricted classes of functionlities ...
Computer simulations of layers I and II of pirifonn (olfactory) cortex indicate that this biological network can generate a series of distinct output responses to individual stimuli, such that different responses encode different levels of information about a stimulus. In particular, after learning a set of stimuli modeled after distinct groups of odors, the simulated networks initial response to a cue indicates only its group or category, whereas subsequent responses to the same stimulus successively subdivide the group into increasingly specific encoding of the individual cue. These sequences of responses amount to an automated organization of perceptual memories according to both their similarities and differences, facilitating transfer of learned information to novel stimuli without loss of specific information about exceptions. Human recognition performance robustly exhibits such multiple levels: a given object can be identified as a vehicle, as an automobile, or as a Mustang. The findings ...
Integrated imaging and GPS network monitors remote object movement. Browser interface displays objects and detectors. Database stores object position movement. Cameras detect objects and generate image signal. Internet provides selectable connection between system controller and various cameras according to object positions.
Integrated imaging and GPS network monitors remote object movement. Browser interface displays objects and detectors. Database stores object position movement. Cameras detect objects and generate image signal. Internet provides selectable connection between system controller and various cameras according to object positions.
In the sustained readiness task (SRT) subjects are required to monitor the succession of presentations of a simple stimulus (red square) and respond as fast as possible at each stimulus onset. The rather long and random inter-trial-intervals (ITI) and the absence of external stimulation other than the red square, make it difficult for the subject to stay alerted (Klemmer, 1957). As such, response latencies are known to increase with fatigue and sedative effects.. The SRT task is only asking for a simple response to each appearance of the same red square without the need to discriminate between different stimuli (Donders, 1969). The SRT task is focusing on decrease in response speed when subjects monitor a simple unpredictable stimulus over an extended period of time. In contrast, vigilance tasks focus primarily on the decrement of discriminating between signal and noise (Davies & Parasuraman, 1982).. The sustained readiness task is an alternative way to measure the concept of sustained ...
A method of manufacturing a portable computing device, involves the steps of (1) maintaining a table comprising stimulus/response data for possible hardware components that may be interfaced in the computing device; (2) performing one manufacturing step in the manufacture of the portable computing device by interfacing one of the possible hardware components with one other component of the computing device; and (3) performing one other manufacturing step in the manufacture by: (i) applying a stimulus to the interfaced hardware component, and reading a response from the interfaced hardware component in response to the applied stimulus; (ii) identifying the interfaced hardware component from a correlation of the response with the stimulus/response data; and (iii) saving the identification as configuration data in the computing device.
Laurens son, Connor, has been struggling with reading and light sensitivity since pre-school. Lauren had Connor take a test to identify whether he had...
Research in the Serre lab focuses on understanding the brain mechanisms underlying the recognition of objects and complex visual scenes using a combination of behavioral, imaging and physiological techniques.
We point out that the seemingly strong pseudorandom oracle preserving (PRO-Pr) property of hash function domain-extension transforms defined and implemented by Coron et. al. [12] can actually weaken our guarantees on the hash function, in particular producing a hash function that fails to be even collision-resistant (CR) even though the compression function to which the transform is applied is CR. Not only is this true in general, but we show that all the transforms presented in [12] have this weakness. We suggest that the appropriate goal of a domain extension transform for the next generation of hash functions is to be multi-property preserving, namely that one should have a single transform that is simultaneously at least collision-resistance preserving, pseudorandom function preserving and PRO-Pr. We present an efficient new transform that is proven to be multi-property preserving in this sense ...
We show a hardness-preserving construction of a PRF from any length doubling PRG which improves upon known constructions whenever we can put a non-trivial upper bound qon the number of queries to...
Research in the Serre lab focuses on understanding the brain mechanisms underlying the recognition of objects and complex visual scenes using a combination of behavioral, imaging and physiological techniques.
There is a puzzle in the FAQ: Remove two opposite corners from a chessboard. Can you cover the remaining 62 squares with dominoes? Answer: No. The remaining board has 32 white and 30 black squares, but each domino must cover one black and one white square. The 56 tiles in a set of Triominoes cannot make a convex shape due to parity. Joseph DeVincentis explains why. Sam Loyd invented the 15-14 puzzle. He offered $1000 to the first person to find a sequence of moves which put at the pieces in order. By parity, this problem was unsolvable. To see this, draw a 3x3 grid and place different objects on a1, a2, c1, and c2. Make moves with the following rule: When one object moves, a different object must move to take its place. Moves are thus paired. Now, swap the objects on a1 and a2. You will find this is possible, but only if the objects on c1 and c2 also swap. John Conway made a block packing problem. You must fit three 1x1x3 boxes, thirteen 1x2x4 boxes, one 1x2x2 box, and one 2x2x2 cube into a ...
GO:0007601. The series of events required for an organism to receive a visual stimulus, convert it to a molecular signal, and recognize and characterize the signal. Visual stimuli are detected in the form of photons and are processed to form an image. ...
Across the entire dataset of 10 decoding sessions per animal, the 50 object conditions could be decoded from the planning epoch with an accuracy of 48.7 ± 3.6 and 51.9 ± 3.4% (mean ± SD) in animals M and Z, respectively. This performance was 23.9× and 26× above chance (2%). During motor execution (i.e., from the hold epoch), the average decoding accuracy was even larger: 62.9 ± 3.6 and 61.4 ± 4.1% (monkeys M and Z, respectively), corresponding to 31.5× and 30.7× above chance (2%). This means that decoding accuracy in the hold epoch was on average 14.2 and 9.5 percentage points higher than in the planning epoch (animals M and Z, respectively). This improvement was significant (p , 0.001, two-way ANOVA) in both animals.. Furthermore, we explored the functional differences of the various cortical areas and recording sites separately in each electrode array: (1) F5lat; (2) F5med; (3) AIPlat; (4) AIPmed; (5) M1lat; and (6) M1med (array numbering as in Fig. 2). To make the analysis fair, we ...
Assayed all keys except for J23202, but Tecan was being wierd and wouldnt give good numbers even though I changed both the integration time and the gain like 20 times. The following results were taken at a gain of 180 and 200 with the max integration time, and the OnRFP is still only in the 1000s rather than the 10000s. Might want to repeat this assay sometime ...
http://phygeo7.geo.uni-augsburg.de/gis2/scripts/v.digatt v.digatt] (shell script) Interactively assign numeric table attributes to series of vector objects. It is meant to be effective by avoiding to type in the attribute value for all single objects again and again. The user is prompted for typing in an attribute value which is assigned to all objects selected by mouseclick afterwards. Next the display is redrawn after updating the table column. Zooming allows to change the region before the old value can be reused or a new one can be typed in (or copied by mouse from another object) in order to assign it to the next series of objects etc. It is tested not very extensively yet. Therefore better work with a copy of your map and consider using v.digit or d.what.vect -e alternatively. [http://phygeo7.geo.uni-augsburg.de/gis2/scripts/v.digatt.png screenshot ...
v.digatt (shell script) Interactively assign numeric table attributes to series of vector objects. It is meant to be effective by avoiding to type in the attribute value for all single objects again and again. The user is prompted for typing in an attribute value which is assigned to all objects selected by mouseclick afterwards. Next the display is redrawn after updating the table column. Zooming allows to change the region before the old value can be reused or a new one can be typed in (or copied by mouse from another object) in order to assign it to the next series of objects etc. It is tested not very extensively yet. Therefore better work with a copy of your map and consider using v.digit or d.what.vect -e alternatively. screenshot ...
The API Im trying to describe has a structure where the root object can contain an arbitrary number of child objects (properties that are themselves objects). The key, or property in the root object, is the unique identifier of the child object, and the value is the rest of the child objects data.. ...
An event is an occurrence of a phenomenon at a certain moment in time. The occurrence of the event itself is assumed to have no duration. Typically, when an event occurs, it affects the state of an object. A state machine is a model of the behaviour of a single object over time and helps you to understand how that objects state affects its reactions to events.. Figure 18 shows a state machine diagram (known as a statechart diagram in the UML) relating to the occupancy of a room in a hot ...
Gene target information for LOC340089 - POM121 membrane glycoprotein (rat) pseudogene (human). Find diseases associated with this biological target and compounds tested against it in bioassay experiments.
Gene target information for Gnptg - N-acetylglucosamine-1-phosphotransferase, gamma subunit (house mouse). Find diseases associated with this biological target and compounds tested against it in bioassay experiments.
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In two experiments, magnetoencephalography (MEG) was used to investigate the effects of motion on gamma oscillations in human early visual cortex. When presented centrally, but not peripherally, stationary and moving gratings elicited several evoked and induced response components in early visual cortex. Time-frequency analysis revealed two nonphase locked gamma power increases-an initial, rapidly adapting response and one sustained throughout stimulus presentation and varying in frequency across observers from 28 to 64 Hz. Stimulus motion raised the sustained gamma oscillation frequency by a mean of approximately 10 Hz. The largest motion-induced frequency increases were in those observers with the lowest gamma response frequencies for stationary stimuli, suggesting a possible saturation mechanism. Moderate gamma amplitude increases to moving versus stationary stimuli were also observed but were not correlated with the magnitude of the frequency increase. At the same site in visual cortex, sustained
ABSTRACT. Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]. It is not known, however, to what extent aging affects visual field representations and population receptive sizes in human primary visual cortex. Here we use functional MRI (fMRI) and population receptive field (pRF) modeling [6] to measure angular and eccentric retinotopic representations and population receptive fields in primary visual cortex in healthy aging subjects ages 57 - 70 and in healthy young volunteers ages 24 - 36 (n = 9). Retinotopic stimuli consisted of black and white, drifting checkerboards comprising moving bars 11 deg in radius. Primary visual cortex (V1) was clearly identifiable along the calcarine sulcus in all hemispheres. There was a significant decrease in the surface area of V1 from 0 to 3 deg eccentricity in the aging subjects with respect to ...
Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]. It is not known, however, to what extent aging affects visual field repre-sentations and population receptive sizes in human primary visual cortex. Here we use func-tional MRI (fMRI) and population receptive field (pRF) modeling [6] to measure angular and ec-centric retinotopic representations and population receptive fields in primary visual cortex in healthy aging subjects ages 57 - 70 and in healthy young volunteers ages 24 - 36 (n = 9). Retinotopic stimuli consisted of black and white, drifting checkerboards comprising moving bars 11 deg in radius. Primary visual cortex (V1) was clearly identifiable along the calcarine sulcus in all hemispheres. There was a significant decrease in the surface area of V1 from 0 to 3 deg eccentricity in the aging subjects with respect to the young
Many pairs of spatial and temporal frequencies in a motion display that result in the same stimulus speed for a moving object can produce different speed percepts (Priebe NJ et al., J Neurosci. 2003, 23(13): 5650-61). We previously reported that judgments of the speed of an object depend on the spatiotemporal frequency of the moving pattern in an inverted-U function, peaking at a specific spatial and temporal frequency combination [http://www.journalofvision.org/4/8/84/]. The location of this peak is largely independent of the size and shape of the object. In the present series of experiments, with the use of high coherence dot motion stimuli, we investigated the dependence of perceived speed on both spatial and temporal frequencies. The perceived speed of the stimulus was estimated using a 2AFC paradigm with interleaved QUEST staircases; subjects were asked to pick the faster of the two spatially separated [6 deg eccentricity] patches of dots moving in opposite directions. We systematically ...
Dive into the research topics of Higher-Order Kernel Responses of Human Electroretinogram Elicited by Full-Field Pseudorandom Flash Stimulus. Together they form a unique fingerprint. ...
In this study, we show that top-down control mechanisms engaged during visual imagery of simple shapes (letters X and O) can selectively activate position-invariant perceptual codes in visual areas specialised for shape processing, including lateral occipital complex (LOC). First, we used multivoxel pattern analysis (MVPA) to identify visual cortical areas that code for shape within a position-invariant reference frame. Next, we examined the similarity between these high-level visual codes and patterns elicited while participants imagined the corresponding stimulus at central fixation. Our results demonstrate that imagery engages object-centred codes in higher-level visual areas. More generally, our results also demonstrate that top-down control mechanisms are able to generate highly specific patterns of visual activity in the absence of corresponding sensory input. We argue that a general model of top-down control must account for dynamic modulation of functional connectivity between high-level control
The simple-cell receptive field (RF) structure is an attractive and unique feature of the primary visual cortex, which is thought to reflect the circuitry principles governing orientation selectivity. Synaptic inputs underlying spike RFs are key to understanding mechanisms for neuronal processing. The well-known push-pull model, which is proposed to explain the synaptic mechanism under simple-cell RFs, predicts that in simple cells the spatially separated excitation and inhibition does not interact with each other and that simple inhibitory neurons exist in the primary visual cortex (V1). However, previous experimental results suggest that synaptic inhibition plays an important role in shaping RF properties in the visual cortex. The synaptic mechanisms underlying simple-cell RFs remain not well understood, partly due to difficulties in systematically studying functional properties of cortical inhibitory neurons and precisely measuring excitatory and inhibitory synaptic inputs in vivo.; In the ...
TY - JOUR. T1 - Recording of reversed Uhthoffs phenomenon by visual evoked potentials elicited by pseudorandom binary sequence stimulation. AU - Mori, H.. AU - Kiyosawa, M.. AU - Nemoto, N.. AU - Mochizuki, M.. AU - Momose, K.. PY - 2001/1/1. Y1 - 2001/1/1. N2 - Reversed Uhthoffs phenomenon is a temporal improvement of visual acuity initiated by body cooling in subjects with demyelinating optic neuropathy. Up until the present, it has been difficult to demonstrate Uhthoffs phenomenon by visually evoked potentials (VEPs). We have been able to demonstrate this phenomenon with VEPs elicited by pseudorandom binary sequence stimuli (PRBS-VEP). Case 1 was a 50-year-old woman with right optic neuropathy. Her right visual acuity was 0.02 and improvement of subjective visual acuity, and temporal frequency characteristics of the VEPs were seen after ingestion of cold water. Case 2 was a 29-year-old man with right optic neuropathy and multiple sclerosis. His right visual acuity was 0.4 and the visual ...
Many current models of working memory (WM) emphasize a close relationship between WM and attention. Recently it was demonstrated that attention can be dynamically and voluntarily oriented to items held in WM, and it was suggested that directed attention can modulate the maintenance of specific WM representations. Here we used event-related functional magnetic resonance imaging to test the effects of orienting attention to a category of stimuli when participants maintained a variable number of faces and scenes in WM. Retro-cues that indicated the relevant stimulus type for the subsequent WM test modulated maintenance-related activity in extrastriate areas preferentially responsive to face or scene stimuli - fusiform and parahippocampal gyri respectively - in a categorical way. After the retro-cue, the activity level in these areas was larger for the cued category in a load-independent way, suggesting the modulation may also reflect anticipation of the probe stimulus. Activity in associative parietal and
© 2019 The Author(s) 2019. Published by Oxford University Press. All rights reserved. The primate visual system contains myriad feedback projections from higher-to lower-order cortical areas, an architecture that has been implicated in the top-down modulation of early visual areas during working memory and attention. Here we tested the hypothesis that these feedback projections also modulate early visual cortical activity during the planning of visually guided actions. We show, across three separate human functional magnetic resonance imaging (fMRI) studies involving object-directed movements, that information related to the motor effector to be used (i.e., limb, eye) and action goal to be performed (i.e., grasp, reach) can be selectively decoded-prior to movement-from the retinotopic representation of the target object(s) in early visual cortex. We also find that during the planning of sequential actions involving objects in two different spatial locations, that motor-related information can be
Previous experimental studies have reported that V1 neurons can respond to a region of uniform luminance (Kinoshita & Komatsu, 2001; Friedman et al., 2003; Roe et al., 2005). Some V1 neurons even show responses modulated by the luminance change of surrounding areas, or flankers that are several degrees away from the their CRFs, while the luminance of the area that covers their CRFs stays constant (Rossi et al., 1996; Rossi & Paradiso, 1999). Some of these neurons show responses that are antiphase to the luminance change of flankers, but show responses in-phase to direct luminance change. These responses are consistent with the human perception of brightness. The modulation of these neurons responses to the simultaneous contrast stimuli cut off at 4 Hz, while the modulation of their responses to direct luminance increases with temporal frequency of the luminance change, which is also consistent to the result shown in human psychophysical studies (Valois, Webster, Valois, & Lingelbach, 1986; ...
Our results provide the first evidence that temporal expectation modulates the power and coherence of gamma responses already at the earliest stage of cortical visual processing. It has been shown that the power and synchronization of gamma oscillations can be modulated by spatial and feature selective attention (Müller et al., 2000; Fries et al., 2001, 2008; Bichot et al., 2005; Taylor et al., 2005; Buschman and Miller, 2007). Our findings extend this notion to the temporal domain.. Fries et al. (2001, 2008) found that gamma synchronization in area V4 was stronger when attention was directed to a stimulus inside the RF. The expectation effects we found in V1 are of comparable magnitude as those found for spatial attention in V4. However, the effects of expectation in V1 are not confined to the attended location (here the fixation point), since the modulation in gamma was comparable for sites recorded simultaneously in the central and peripheral representations of the visual field. These ...
Visual cortex is traditionally viewed as a hierarchy of neural feature detectors, with neural population responses being driven by bottom-up stimulus features. Conversely, predictive coding models propose that each stage of the visual hierarchy harbors two computationally distinct classes of processing unit: representational units that encode the conditional probability of a stimulus and provide predictions to the next lower level; and error units that encode the mismatch between predictions and bottom-up evidence, and forward prediction error to the next higher level. Predictive coding therefore suggests that neural population responses in category-selective visual regions, like the fusiform face area (FFA), reflect a summation of activity related to prediction (face expectation) and prediction error (face surprise), rather than a homogenous feature detection response. We tested the rival hypotheses of the feature detection and predictive coding models by collecting functional magnetic resonance
Spike count correlations (SCCs), covariation of neuronal responses across multiple presentations of the same stimulus, are ubiquitous in sensory cortices and span different modalities (1⇓-3) and processing stages (4⇓⇓-7). In the visual system, SCCs, also termed noise correlations, have traditionally been considered to be independent of the stimulus and hence have been thought to impede stimulus encoding (8). Studies on stimulus-independent aspects of SCCs in the primary visual cortex (V1) sought to capture correlation patterns that were solely accounted for by differences in receptive field structure (9, 10). Initial investigations of dependence of SCCs on low-level stimulus features, such as orientation and contrast, focused on the population mean of SCCs (11⇓-13), but stimulus-dependent changes in the mean are modest in awake animals (9, 14). Only recently has orientation and contrast dependence of the fine structure of SCCs been demonstrated in anesthetized cats and awake mice (15). ...
A key attribute of the brain is its ability to seamlessly integrate sensory information to form a multisensory representation of the world. In early perceptual processing, the superior colliculus (SC) takes a leading role in integrating visual, auditory and somatosensory stimuli in order to direct eye movements. The SC forms a representation of multisensory space through a layering of retinotopic maps which are sensitive to different types of stimuli. These eye-centered topographic maps can adapt to crossmodal stimuli so that the SC can automatically shift our gaze, moderated by cortical feedback. In this paper we describe a neural network model of the SC consisting of a hierarchy of nine topographic maps that combine to form a multisensory retinotopic representation of audio-visual space. Our motivation is to evaluate whether a biologically plausible model of the SC can localize audio-visual inputs live from a camera and two microphones. We use spatial contrast and a novel form of temporal ...
During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioral and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioral data when studying the neural correlates of prospective control ...
Orienting spatial attention to locations in the extrapersonal world has been intensively investigated during the past decades. Recently, it was demonstrated that it is also possible to shift attention to locations within mental representations held in working memory. This is an important issue, since the allocation of our attention is not only guided by external stimuli, but also by their internal representations and the expectations we build upon them. The present experiment used behavioural measures and event-related functional magnetic resonance imaging to investigate whether spatial orienting to mental representations can modulate the search and retrieval of information from working memory, and to identify the neural systems involved, respectively. Participants viewed an array of coloured crosses. Seconds after its disappearance, they were cued to locations in the array with valid or neutral cues. Subsequently, they decided whether a probe stimulus was presented in the array. The behavioural results
A large extent of the posterior cortex of the primate brain is devoted to vision, and it contains two general streams that process visual information. The one stream is situated more ventrally in the cortex and is important for object recognition, pattern recognition, color perception, and shape perception. These attributes of visual analysis we associate with visual awareness or seeing, and thus this stream has been referred to as the what system because it recognizes objects (Ungerleider and Mishkin 1982). A second, more dorsal stream is associated with visual-motor transformations-that is, the routing of sensory information into motor areas for the purpose of action. This dorsal stream plays an important role in attention, decisions, and movement planning. It also plays an important role in spatial awareness, which is crucial for planning movements to locations in space and for transforming visually defined locations into movement coordinates to accomplish accurate motor behaviors. This ...
In an attempt to understand how low-level visual information contributes to object categorisation, previous studies have examined the effects of spatially filtering images on object recognition at different levels of abstraction. Here, the quantitative thresholds for object categorisation at the basic and subordinate levels are determined by using a combination of the method of adjustment and a match-to-sample method. Participants were asked to adjust the cut-off of either a low-pass or high-pass filter applied to a target image until they reached the threshold at which they could match the target image to one of six simultaneously presented category names. This allowed more quantitative analysis of the spatial frequencies necessary for recognition than previous studies. Results indicate that a more central range of low spatial frequencies is necessary for subordinate categorisation than basic, though the difference is small, at about 0.25 octaves. Conversely, there was no effect of categorisation level
Objects that are semantically related to the visual scene context are typically better recognized than unrelated objects. While context effects on object recognition are well studied, the question which particular visual information of an objects surroundings modulates its semantic processing is still unresolved. Typically, one would expect contextual influences to arise from high-level, semantic components of a scene but what if even low-level features could modulate object processing? Here, we generated seemingly meaningless textures of real-world scenes, which preserved similar summary statistics but discarded spatial layout information. In Experiment 1, participants categorized such textures better than colour controls that lacked higher-order scene statistics while original scenes resulted in the highest performance. In Experiment 2, participants recognized briefly presented consistent objects on scenes significantly better than inconsistent objects, whereas on textures, consistent objects were
Stimulus modality, also called sensory modality, is one aspect of a stimulus or what we perceive after a stimulus. For example, the temperature modality is registered after heat or cold stimulate a receptor. Some sensory modalities include: light, sound, temperature, taste, pressure, and smell. The type and location of the sensory receptor activated by the stimulus plays the primary role in coding the sensation. All sensory modalities work together to heighten stimuli sensation when necessary. Multimodal perception is the ability of the mammalian nervous system to combine all of the different inputs of the sensory nervous system to result in an enhanced detection or identification of a particular stimulus. Combinations of all sensory modalities are done in cases where a single sensory modality results in ambiguous and incomplete result. Integration of all sensory modalities occurs when multimodal neurons receive sensory information which overlaps with different modalities. Multimodal neurons are ...
Visual images of our own and others body parts can be highly similar, but the types of information we wish to extract from them are highly distinct. From our own body we wish to combine visual information with, at least, somatosensory, proprioceptive and motor information in order to guide our interpretation of sensory events and our actions upon the world. For others bodies we only have visual information available, but from that we can derive much useful social information including their age, health, gender, emotional state and intentions. Consequently, a challenge for the brain is to sort visual images of our own bodies, to be integrated with processing from other sensory modalities, from highly similar images of others bodies for social cognition. We explored the possibility that the extrastriate body area (EBA) may help to accomplish this sorting. Previous work had suggested that the EBA is responsive to images of both our own and others body parts but does not distinguish between ...
Author Summary How can humans and animals make complex decisions on time scales as short as 100 ms? The information required for such decisions is coded in neural activity and should be read out on a very brief time scale. Traditional approaches to coding of neural information rely on the number of electrical pulses, or spikes, that neurons fire in a certain time window. Although this type of code is likely to be used by the brain for higher cognitive tasks, it may be too slow for fast decisions. Here, we explore an alternative code which is based on the latency of spikes with respect to a reference signal. By analyzing the simultaneous responses of many cells in monkey visual cortex, we show that information about the orientation of visual stimuli can be extracted reliably from spike latencies on very short time scales.
Together, (1)-(4) entail:. ATTENTIONAL MODULATION: Non-spatial forms of cognitively directed attention affect perceptual experience by affecting perceptual processing itself.. Two brief preliminary remarks are in order. First, (1)-(4) only entail ATTENTIONAL MODULATION if the form of attention is kept constant across all four claims. For instance, if (1) is established by evidence in favor of the existence of feature- or object-based attention and (2)-(4) are established by evidence relating to spatial attention, then ATTENTIONAL MODULATION is not established. Second, ATTENTIONAL MODULATION provides evidence against the rudimentary view of attention discussed earlier according to which attention is a simple mechanism analogous to a spatial spotlight that operates pre-perceptually. Accepting ATTENTIONAL MODULATION challenges anything akin to a spatial spotlight model of attention and provides evidence that attentions modulatory role in perception is not indirect. An acceptance of this ...
When objects disappear from view, we can still bring them to mind, at least for brief periods of time, because we can represent those objects in visual short-term memory (VSTM) (Sperling, 1960; Cowan, 2001). A defining characteristic of this representation is that it is topographic, that is, it preserves a spatial organization based on the original visual percept (Vogel and Machizawa, 2004; Astle et al., 2009; Kuo et al., 2009). Recent research has also shown that features or locations of visual items that match those being maintained in conscious VSTM automatically capture our attention (Awh and Jonides, 2001; Olivers et al., 2006; Soto et al., 2008). But do objects leave some trace that can guide spatial attention, even without participants intentionally remembering them? Furthermore, could subliminally presented objects leave a topographically arranged representation that can capture attention? We presented objects either supraliminally or subliminally and then 1 s later re-presented one of those
In this study, we bridge the gap between monkey electrophysiological recordings that showed selective responses to informative features and human fMRI data that demonstrated increased and selective responses to trained objects. Human participants trained with computer-generated fish stimuli. For each participant, two features of the fish were informative for category membership and two features were uninformative. After training, participants showed higher perceptual sensitivity to the informative dimensions. An fMRI adaptation paradigm revealed that during categorization the right inferior frontal gyrus and occipitotemporal cortex were selectively responsive to the informative features. These selective cortical responses were experience dependent; they were not present for the entire trained object, but specific for those features that were informative for categorization. Responses in the inferior frontal gyrus showed category selectivity. Moreover, selectivity to the informative features ...
Neurite arbors of VGluT3-expressing amacrine cells (VG3-ACs) process visual information locally uniformly detecting object motion while varying in contrast preferences; and in spite of extensive overlap between arbors of neighboring cells population activity in the VG3-AC plexus encodes stimulus positions with subcellular precision.
Chen, S., Shi, Z., Müller, H. J., & Geyer, T. (2021). Multisensory visuo-tactile context learning enhances the guidance of unisensory visual search. Scientific Reports, 11(1), 9439. https://doi.org/10.1038/s41598-021-88946-6 Abstract Does multisensory distractor-target context learning enhance visual search over and above unisensory learning? To address this, we had participants perform a visual search task under both uni- and multisensory conditions. Search arrays consisted of one Gabor target that differed from three homogeneous distractors in orientation; participants had to discriminate the targets orientation. In the multisensory session, additional tactile (vibration-pattern) stimulation was delivered to two fingers of each hand, with the odd-one-out tactile target and the distractors co-located with the corresponding visual items in half the trials; the other half presented the visual array only. In both sessions, the visual target was embedded within identical ...
parametric_volume=None, grid=None, import_grid_file_name=None, nni=None, nnj=None, nnk=None, cf_list=[None, None, None, None, None, None, None, None, None, None, None, None], bc_list=[,bc_defs.SlipWallBC object at 0x2b56835dddd0,, ,bc_defs.SlipWallBC object at 0x2b56835dddd0,, ,bc_defs.SlipWallBC object at 0x2b56835dddd0,, ,bc_defs.SlipWallBC object at 0x2b56835dddd0,, ,bc_defs.SlipWallBC object at 0x2b56835dddd0,, ,bc_defs.SlipWallBC object at 0x2b56835dddd0,], wc_bc_list=[,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,, ,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,, ,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,, ,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,, ,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,, ,bc_defs.NonCatalyticWBC object at 0x2b5685bb1890,], fill_condition=None, hcell_list=None, mcell_list=None, xforce_list=[0, 0, 0, 0, 0, 0], zforce_list=[0, 0, 0, 0, 0, 0], transient_profile_faces=[], label=, active=1, omegaz=0.0, verbosity_level=0)¶ ...
Hi there, Ive built a horizontally scrollable hbox layout container, docked on top, filled with other sub-containers, which I want to transform into a vbox layout (scrollable vertically, docked to the left) on orientation change. Right now Im doing something like this on resize: var hboxLayout = Ext.getCmp(hboxLayoutID); Ext.getCmp(hboxLayoutParentID).removeAll(false, true);
Amodal categorization is the grouping of common stimuli independent of the modality of sensory input. Primates show behavioural signs of amodal categorization/cross-modal equivalence. When provided with an object to inspect haptically, apes and monkeys were able to generalize what they had learned to the visual modality (Davenport & Rogers 1970; Weiskrantz & Cowey 1975; Elliot 1977). In addition, when monkeys (or humans) were expected to categorize vocalizations, prior presentation of conceptually congruent images led to faster responses (Martin-Malivel & Fagot 2001). This demonstrates an independence of the perceptual attributes of a stimulus to categorization, something that should be incorporated more explicitly in the aforementioned models of object categorization.. We do not yet know the neural basis for amodal processing, and, indeed, there may be biases for some stimulus pairings across modality that are innate or biased early in development, and therefore are not consistent with other ...
Categorization is a process by which the brain assigns meaning to sensory stimuli. Through experience, we learn to group stimuli into categories, such as chair, table and vehicle, which are critical for rapidly and appropriately selecting behavioural responses. Although much is known about the neural representation of simple visual stimulus features (for example, orientation, direction and colour), relatively little is known about how the brain learns and encodes the meaning of stimuli. We trained monkeys to classify 360° of visual motion directions into two discrete categories, and compared neuronal activity in the lateral intraparietal (LIP) and middle temporal (MT) areas, two interconnected brain regions known to be involved in visual motion processing. Here we show that neurons in LIP-an area known to be centrally involved in visuo-spatial attention, motor planning, and decision-making -- robustly reflect the category of motion direction as a result of learning. The activity of LIP ...
One strong claim made by the representational-hierarchical account of cortical function in the ventral visual stream (VVS) is that the VVS is a functional continuum: The basic computations carried out in service of a given cognitive function, such as recognition memory or visual discrimination, might be the same at all points along the VVS. Here, we use a single-layer computational model with a fixed learning mechanism and set of parameters to simulate a variety of cognitive phenomena from different parts of the functional continuum of the VVS: recognition memory, categorization of perceptually related stimuli, perceptual learning of highly similar stimuli, and development of retinotopy and orientation selectivity. The simulation results indicate-consistent with the representational-hierarchical view-that the simple existence of different levels of representational complexity in different parts of the VVS is sufficient to drive the emergence of distinct regions that appear to be specialized for ...
Simple features, such as particular edges of the image in a specific orientation, are extracted at the first cortical processing stage, called the primary visual cortex, or V1. Then subsequent cortical processing stages, V2, V4, etc., extract progressively more complex features, culminating in the inferotemporal cortex where that essential viewpoint invariant object identification is thought to occur. But, most of the connections in the human brain do not project up the cortical hierarchy, as might be expected from gross neuroanatomy, but rather connect neurons located at the same hierarchical level, called lateral connections, and also project down the cortical hierarchy to lower processing levels ...
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The body is designed in a way wherein the different sense organs work with the brain for the interpretation of the different senses so that we can exhibit the appropriate responses, both behavioral and motor. However, there are instances when the responses are not proper because of misinterpretation of the senses. This condition is called sensory processing disorder.. Sensory processing disorder (SPD) was formerly known as sensory integration dysfunction was first described by A. Jean Ayres, a neuroscientist who said that this disorder is similar to a traffic jam that occurs in the neurons, wherein some parts of the brain are prevented from receiving the correct information so that sensory information are interpreted correctly. For someone who has SPD, what happens is that sensory information is perceived differently from that which is normal to other people. This will then result in behavior or responses that are unusual, which makes it hard to accomplish some tasks.. The exact causes of ...
Academic performance enhancement with photic stimulation and EDR feedback. Journal of Neurotherapy, 3, 11-21. Budzynski, T.H. ( ... He conducted studies on the effects of audio-visual stimulation on the brain; the priming effects of binaural tones as measured ... In P. Suedfeld, J.W. Turner, Jr., & T.H. Fine (Eds.), Restricted Environmental Stimulation: Theoretical and Empirical ... 2000). Reversing age-related cognitive decline: Use of neurofeedback and audio-visual stimulation. Biofeedback, 28, 19-21. ...
Dewan, Edmond M.; Menkin, Miriam F.; Rock, John (1978-05-01). "Effect of Photic Stimulation on the Human Menstrual Cycle". ...
Intermittent photic stimulation may precipitate or facilitate absence seizures; eyelid myoclonia is a common clinical feature.[ ...
Intermittent photic stimulation, a neuroimaging technique. *Intraparietal sulcus, a region of the brain ...
A large area of skin must be stimulated to affect brainwaves, which leaves both auditory and photic stimulation as the most ... Huxley and Walter were among the first to articulate the subjective correlates of photic stimulation. They described subjective ... Anderson, D. (1989) The treatment of migraine with variable frequency photic stimulation. Headache, 29, 154-155. Gagnon, C., & ... photic and auditory stimulation are capable of affecting brain wave activity. ...
These discharges may be evoked by photic stimulation (blinking lights) and/or hyperventilation. Both a magnetic resonance ...
"Does visual cortex lactate increase following photic stimulation in migraine without aura patients? A functional (1)H-MRS study ... visual stimulation and allowed the generalization of findings based on visual stimulation to other types of stimulation, e.g., ... has been proposed as an alternative to the BOLD fMRI technique and used to detect visual response to photic stimulation, motor ... of fMRS to measure chemical processes in the brain over time proved crucial for confirming that repetitive photic stimulation ...
"Cortical response of the anaesthetized cat to gross photic and electrical afferent stimulation". Journal of Neurophysiology. 6 ... Kemp, E. H.; Coppée, G. E.; Robinson, E. H. (1937). "Electric responses of the brain stem to unilateral auditory stimulation". ... wherein most of the g-related brain activity occurs following stimulation evaluation but before motor response, while ...
These patients do not need to produce conditions of intermittent photic stimulation for self-induction. Simply closing the eyes ... Photoparoxysmal discharges induced by photic stimulation occur in all untreated young patients, but may be absent in older ...
These procedures include hyperventilation, photic stimulation (with a strobe light), eye closure, mental activity, sleep and ... Beck placed electrodes directly on the surface of the brain to test for sensory stimulation. His observation of fluctuating ... I. Evoked responses after thalamic and epicortical stimulation". Electroencephalography and Clinical Neurophysiology. 20 (1): 1 ... somatosensory and cross-modal stimulation". Clinical Neurophysiology. 117 (11): 2549-63. doi:10.1016/j.clinph.2006.08.003. PMC ...
This method works to reduce the stimulation affecting the ophthalmic branch, thus reducing the stimulation of the trigeminal ... The symptoms of photic headshakers lessen when indoors and during the nighttime. Headshaking appears to occur in horses all ... This side of the syndrome is termed "photic headshaking" and is thought to occur due to the close proximity of the optic and ... Percutaneous electrical Nervous stimulation (PENS) is used as a treatment for human patients with trigeminal facial nerve pain ...
More precise investigation can be carried out by combining an EEG with a device producing Intermittent Photic Stimulation (IPS ... Many people will show PSE-like abnormalities in brain activity with sufficiently aggressive stimulation, but they never ...
The waves of bioluminescence that move within a colony are apparently not propagated by neurons, but by a photic stimulation ...
Stimulation of the periaqueductal gray area elicited ipsilateral spinal bending while stimulation of the ventral tegmental area ... Another system that non-invasively controls rats uses ultrasonic, epidermal and LED photic stimulators on the back. The system ... In 1967, Franz Huber pioneered electrical stimulation to the brain of insects and showed that mushroom body stimulation elicits ... Stimulation of basalar flight muscles allowed the controller to direct the insect left or right, although this was successful ...
This "stroboscopic photo-stimulation produces "photic driving", the alpha type of brain electrical activity associated with an ... But also tactile and emotional changes are reported after a 6 Hz photic stimulation, as well as auditory hallucinations like ... Photic mind machines work with flickering lights embedded in sunglasses or a lamp that sits on a tripod above your head or ... Clinical research has been done on the use of auditory and visual stimulation to improve cognitive abilities in learning- ...
The EEG arousal response to auditory stimulation and to electric stimulation of the mesencephalic reticular formation, ... The photic driving response elicited by a flash light in the visual cortex is significantly suppressed by estazolam. A primate ...
The EEG arousal response to auditory stimulation and to electric stimulation of the mesencephalic reticular formation, ... The photic driving response elicited by a flash light in the visual cortex is also suppressed by nitrazepam. Estazolam was ... Very infrequently, paradoxical reactions may occur, for example, excitement, stimulation, hallucinations, hyperactivity, and ... after median nerve stimulation to be prolonged and the N20 to be dispersed. Brain-stem auditory evoked potentials demonstrate ...
The photic response is likely linked to effects of light on circadian rhythms. In addition, focal application of melatonin can ... Many SCN neurons are sensitive to light stimulation via the retina, and sustainedly firing action potentials during a light ...
... sexual stimulation etc.; Photic or Visual: driving through the sense of sight by yantra, visual story telling, mandala, cinema ... in the use of brain machines suggest that photic driving via the suprachiasmatic nucleus and direct electrical stimulation and ... "Eliciting the Photic Driving Response" which states that the EEG photic driving response is a sensitive neurophysiological ... Photic driving also impacts upon the psychological climate of a person by producing increased visual imagery and decreased ...
... and photic stimulation (light therapy.) Neurointegration therapy begins with a brain mapping session using qEEG to help ...
... may refer to: Intermittent photic stimulation as diagnostic procedure Any stimulation involving photons This ... disambiguation page lists articles associated with the title Photic stimulation. If an internal link led you here, you may wish ...
In many people who show the photic sneeze reflex, even this direct stimulation can lead to a photic sneeze which is why we find ... A photic sneeze results from exposure to a bright light and is the most common manifestation of the photic sneeze reflex. This ... of photic sneezers, and Caucasians represent 94%. The study also found statistically significant correlations between photic ... Those affected by photic sneezing may find relief by shielding their eyes and/or faces with hats, scarves, and sunglasses, or ...
In medicine, Intermittent Photic Stimulation, or IPS, is a form of visual stimulation used in conjunction with ... Photic stimulation may also be used to elicit myoclonus, especially cortical reflex myoclonus when present in photo-sensitive ... symptoms and signs during intermittent photic stimulation and their relation to seizures in daily life". Journal of Neurology, ... IPS is often used in conjunction with other controllable generators of visual stimuli, such as low-level visual stimulation ...
Photic sneeze reflex is a reflex condition that causes sneezing in response to looking at bright lights. Paroxysmal sneezing in ... Parasympathetic stimulation causes not only excessive secretion from the nasal gland but also vasodilatation and engorgement, ... Sympathetic stimulation causes vasoconstriction and shrinkage of mucosa, which leads to decongestion of the nose. ...
Breitenbach RA, Swisher PK, Kim MK, Patel BS (December 1993). "The photic sneeze reflex as a risk factor to combat pilots". ... Sneezing is also triggered by sinus nerve stimulation caused by nasal congestion and allergies. The neural regions involved in ... a condition known as photic sneeze reflex (PSR). Walking out of a dark building into sunshine may trigger PSR, or the ACHOO ( ...
Gross PM, Wainman DS, Chew BH, Espinosa FJ, Weaver DF (March 1993). "Calcium-mediated metabolic stimulation of neuroendocrine ... Lowrey PL, Takahashi JS (2000). "Genetics of the mammalian circadian system: Photic entrainment, circadian pacemaker mechanisms ...
The light organ of P. pyralis is composed of two layers; a layer of refractile cells on the dorsal side and a photic layer with ... Excretion of unpleasant fluids from the areas along the elytra and pronotum is the result of tactile stimulation and has been ... Case, J.F. (2004). "Flight studies on photic communication by the firefly Photinus pyralis". Integrative and Comparative ...
Consequently, stimulation of melanopsin in ipRGCs mediates behavioral and physiological responses to light, such as pupil ... Melatonin was not only suppressed in visually unimpaired humans, but also in blind participants, suggesting that the photic ... July 2003). "Melanopsin is required for non-image-forming photic responses in blind mice". Science. 301 (5632): 525-7. Bibcode: ... are half as effective for melanopsin photoreceptor stimulation as light at 480 nm. Melanopsin in the iris of some, primarily ...
The zeitgeber found to have the most profound effect on the SCN is light, which is the form of stimulation of which conversion ... The retinohypothalamic tract (RHT) is a photic neural input pathway involved in the circadian rhythms of mammals. The origin of ... day and higher at night because humans are exposed to light more during the day and are having greater optic nerve stimulation ...
"Behavioral response of sharks to electric stimulation". Bulletin of Seikai National Fisheries Research Institute. 78: 13-30.. ...
These procedures include hyperventilation, photic stimulation (with a strobe light), eye closure, mental activity, sleep and ... I. Evoked responses after thalamic and epicortical stimulation". Electroencephalography and Clinical Neurophysiology. 20 (1): 1 ... Beck placed electrodes directly on the surface of the brain to test for sensory stimulation. His observation of fluctuating ... somatosensory and cross-modal stimulation". Clinical Neurophysiology. 117 (11): 2549-63. doi:10.1016/j.clinph.2006.08.003. PMC ...
The retinohypothalamic tract (RHT) is a photic neural input pathway involved in the circadian rhythms of mammals.[1] The origin ... which is the form of stimulation of which conversion is needed for it to be processed by the brain. Neurotransmitters that ... day and higher at night because humans are exposed to light more during the day and are having greater optic nerve stimulation ...
In marine systems, hydrogen peroxide (H2O2) exists at concentrations of 10−8-10−9 M in the photic zone, but has been found in ... Stimulation by Hepes buffer". The Biochemical Journal. 254 (2): 519-23. doi:10.1042/bj2540519. PMC 1135108 . PMID 3178771. K., ...
In pigeons, there is evidence of a FEO that functions separately from photic-entrainable oscillators. The experimental design ... The SCN can inhibit or activate hypothalamic behavior that stimulates behavior, neuroendocrine stimulation for hormone ...
Further studies have found that echolocation below the photic zone could have been a predation adaptation to diel migrating ... the movement of the basilar membrane results in the stimulation of primary auditory neurons. Many of these neurons are ... or allow odontocetes to invade and feed at depths below the photic zone. ...
Stimulation of metamorphosis in an estuarine crab, Chasmagnathus granulata (Dana, 1851): temporal window of cue receptivity. J ... vertical migrations between deeper waters with less light and fewer predators during the day and shallow waters in the photic ...
In 2002, Hattar and his colleagues showed that melanopsin plays a key role in a variety of photic responses, including ... In addition, T7 mice exhibited impaired hippocampal long-term potentiation (LTP) when subjected to theta burst stimulation (TBS ... such as photic entrainment and pupillary light reflex. Hattar, armed with the knowledge that melanopsin was the photopigment ...
Photic stimulation may refer to: Intermittent photic stimulation as diagnostic procedure Any stimulation involving photons This ... disambiguation page lists articles associated with the title Photic stimulation. If an internal link led you here, you may wish ...
In medicine, Intermittent Photic Stimulation, or IPS, is a form of visual stimulation used in conjunction with ... Photic stimulation may also be used to elicit myoclonus, especially cortical reflex myoclonus when present in photo-sensitive ... symptoms and signs during intermittent photic stimulation and their relation to seizures in daily life". Journal of Neurology, ... IPS is often used in conjunction with other controllable generators of visual stimuli, such as low-level visual stimulation ...
Age-related variation in EEG complexity to photic stimulation: a multiscale entropy analysis.. Takahashi T1, Cho RY, Murata T, ... This study was intended to examine variations in electroencephalographic (EEG) complexity in response to photic stimulation (PS ... Age-related variation in EEG complexity to photic stimulation: A multiscale entropy analysis ... Age-related variation in EEG complexity to photic stimulation: A multiscale entropy analysis ...
A visual illusion consisting of transparent halos extending beyond the boundaries of rotating discs is reported. The effect can be obtained by rotating a variety of black-and-white discs at moderate speeds. It is not due ...
Retinal glucose metabolism and blood flow: Effects of photic stimulation. Wang, Lin Uppsala University, Medicinska ...
On and off effects in the background electro encephalogram activity during 1 second photic stimulation ... Interaction between intermittent photic stimulation and auditory stimulation on the human electro encephalogram preliminary ... Testosterone effects upon photic stimulation of the electro encephalogram and mental performance of humans. Perceptual & Motor ... The effects of combined hyper ventilation and intermittent photic stimulation on the electro encephalogram of psychiatric ...
... encephalographic analysis in patients with ischemic cerebro vascular disease electro encephalogram during photic stimulation ... On the facilitation and occlusion of electro encephalogram by cyclic photic and somatic stimulation of patients with cerebro ... On the electro encephalographic response to cyclic photic stimulation in patients with cerebro vascular diseases. Journal of ... Labyrinthine stimulation and its effects on the autonomic nervous system the electro encephalogram and nystagmus in patients ...
Dynamic visual stimulation also called as intermittent photic stimulation is used in psychophysical studies of brain to an ... In this study, we will use MEG to study the response of brain to a dynamic photic stimulation that has been recently shown to ... Psychophysical study of brain with intermittent photic stimulation using magnetoencephalography (MEG). Authors: Pandarinathan, ... A novel photic stimulator that is compatible to function inside MEG setup is used. This stimulator uses a fiber optic cable to ...
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wp-content/uploads/2016/03/[email protected] 0 0 syn-admin /wp-content/uploads/2016/03/[email protected] syn-admin2012-07-15 00:12:202016-02-08 17:03:10Molecular tools and approaches for optogenetics. ...
Methods 20 healthy subjects were stimulated with rACS as well as photic stimulation and reported adverse events following ... healthy subjects were stimulated with rACS as well as photic stimulation and reported adverse events following stimulation. We ... Stimulation parameters and finite element modeling estimates of rACS were found to be well below existing safety limits. No ... Stimulation parameters and finite element modeling estimates of rACS were found to be well below existing safety limits. No ...
Photic Stimulation* * Proteasome Endopeptidase Complex * RNA, Messenger / metabolism * RNA, Messenger / radiation effects ... Photic regulation of melatonin in rat retina and the role of proteasomal proteolysis Neuroreport. 2001 Dec 4;12(17):3833-7. doi ...
The intermittent photic stimulation showed an increased effectiveness when combined with patterns and this may be due to an ... It has been found that intermittent photic stimulation is more effective on "eye-closure" than in any other eye state and more ... induced by intermittent photic stimulation have been studied. The majority of photosensitive epileptic patients and those with ... A study of photosensitive epilepsy with particular reference to occipitial spikes induced by intermittent photic stimulation. ...
Morphologic Changes in Rats Pineal Gland After Eliminating Retinal Photic Stimulation. Cambios Morfológicos en la Glándula ... KEY WORDS: Pineal gland; Rat; Photic stimulation; Pinealocytes.. RESUMEN: La secreción de melatonina por parte de glándula ... These results give an indirect evidence of the effect that photic stimulation suppression has in the pineal gland in rats. ... cells associated with the elimination of photic stimulation in rats by means of retinal damage. By histological analysis of the ...
... undergraduate college student volunteers were randomly assigned to three groups which received intermittent photic stimulation ... Guilford, "The Effects of Intermittent Photic Stimulation upon Respiration Rate and Anxiety" (1985). Masters Theses. 1387. ... undergraduate college student volunteers were randomly assigned to three groups which received intermittent photic stimulation ...
Core Concept: Can deep brain stimulation find success beyond Parkinsons disease?. Some researchers are aiming to apply the ... Photic memory for executive brain responses. Sarah Laxhmi Chellappa, Julien Q. M. Ly, Christelle Meyer, Evelyne Balteau, ... This recently discovered photopigment may therefore provide a unique form of "photic memory" for human cognition and play a ... In humans, evidence for melanopsin involvement in light-driven cognitive stimulation remains indirect, due to the difficulty to ...
This endogenous rhythm was remarkably modulated by photic stimulation. Under LD conditions, the NPY content in the SCN ... Photic regulation of peptides located in the ventrolateral subdivision of the suprachiasmatic nucleus of the rat: daily ... Photic regulation of peptides located in the ventrolateral subdivision of the suprachiasmatic nucleus of the rat: daily ... Photic regulation of peptides located in the ventrolateral subdivision of the suprachiasmatic nucleus of the rat: daily ...
Photic Stimulation * Reaction Time / physiology* * Reference Values * Saccades / physiology* ...
Photic Stimulation. *Psychomotor Performance/drug effects/*physiology. *Subthalamic Nucleus/drug effects/*physiology/*phys ... using high frequency stimulation (HFS). In both Parkinsons disease and OCD patients, STN-HFS can trigger abnormal behaviours, ... we recorded subthalamic local field potentials in 16 patients with Parkinsons disease using deep brain stimulation electrodes ... which may underlie the behavioural changes observed in patients with deep brain stimulation. ...
Intermittent photic stimulation, a neuroimaging technique. *Intraparietal sulcus, a region of the brain ...
3C). Photic stimulation (100 lux, 15 min) at CT 15 triggered a 1.90 ± 0.25 h phase delay in double transgenic mice, and a 2.28 ... For all other photic stimulation assays, mice were entrained to a 12:12 LD cycle (400 lux), dark-adapted for 2 days, exposed to ... For the photic stimulation paradigm, cages were removed from the cabinet, placed in a secondary containment chamber and exposed ... Behavioral and photic stimulation paradigms. Mice were individually housed in polycarbonate cages equipped with a running wheel ...
Eye of the Tiger Sign on MRI & Increased Urinary Dopamine and Dopamine Metabolites (Paradoxical) & Polyspike on Photic ... Stimulation Symptom Checker: Possible causes include Benign Adult Familial Myoclonic Epilepsy. Check the full list of possible ... Six patients had response to hyperventilation and 10 had paroxysmal photic response (PPR) to photic stimulation. [annalsofian. ... Intermittent photic stimulation may trigger generalized spike-and-wave and polyspike-and-wave, and myoclonic-atonic seizures. [ ...
Full text: Available Index: WPRIM (Western Pacific) Main subject: Photic Stimulation / Blinking / Female / Humans / Male / ... Full text: Available Index: WPRIM (Western Pacific) Main subject: Photic Stimulation / Blinking / Female / Humans / Male / ... Effect of eyes closure, eyes closed and photic stimulation on the epileptiform discharges in children with epilepsies / 中华儿科杂志 ... Effect of eyes closure, eyes closed and photic stimulation on the epileptiform discharges ...
Photic Stimulation • Pigmentation • Pigments, Biological • Plants • Polymorphism, Genetic • Polymorphism, Single Nucleotide • ... Electric Stimulation • Electron Transport Complex IV • Embryonic and Fetal Development • Embryonic Development • Energy Intake ...
during and afer photic and HV stimulation. Interpretation:. Abnormal EEG result. Epileptic disorder with right fronto-temporal ...
inconsistent photoparoxysmal response when stimulated by photic stimulation. Other protocol-defined inclusion/exclusion ...
... or auto-photic stimulation (APS) interventions [58]. The study targeting social anxiety disorder was a treatment study ...
Photic Stimulation. Photometry. Grant Support. ID/Acronym/Agency: EY 05325/EY/NEI NIH HHS ...
... known as suprachoroidal-transretinal stimulation (STS), which was designed to minimize insult to the retina by implantation of ... Assessment of a novel method of retinal stimulation, ... Photic Stimulation. Rats. Rats, Long-Evans. Rats, Mutant ... Electric Stimulation. Electric Stimulation Therapy / methods*. Electrodes, Implanted. Evoked Potentials, Visual / physiology*. ... PURPOSE: Assessment of a novel method of retinal stimulation, known as suprachoroidal-transretinal stimulation (STS), which was ...
Photic Stimulation. Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light ...
  • Photic stimulation may refer to: Intermittent photic stimulation as diagnostic procedure Any stimulation involving photons This disambiguation page lists articles associated with the title Photic stimulation. (wikipedia.org)
  • In medicine, Intermittent Photic Stimulation, or IPS, is a form of visual stimulation used in conjunction with electroencephalography to investigate anomalous brain activity triggered by specific visual stimuli, such as flashing lights or patterns. (wikipedia.org)
  • Dynamic visual stimulation also called as intermittent photic stimulation is used in psychophysical studies of brain to an intermittently flickering light. (ntu.edu.sg)
  • The aspects dealt with were mainly concerned with electroencephalographic responses to intermittent photic stimulation. (aston.ac.uk)
  • It has been found that intermittent photic stimulation is more effective on "eye-closure" than in any other eye state and more abnormalities are induced when the eyes are open than when they are closed. (aston.ac.uk)
  • The characteristics of the occipital spikes induced by intermittent photic stimulation have been studied. (aston.ac.uk)
  • The majority of photosensitive epileptic patients and those with epilepsy who are not clinically photosensitive but in whom E.G. abnormalities are provoked by intermittent photic stimulation, show occipital spikes alone or preceding photoconvulsive responses, during photic stimulation. (aston.ac.uk)
  • The intermittent photic stimulation showed an increased effectiveness when combined with patterns and this may be due to an increased susceptibility of the occipital cortex. (aston.ac.uk)
  • Forty undergraduate college student volunteers were randomly assigned to three groups which received intermittent photic stimulation (IPS) and a control group which did not receive IPS. (wmich.edu)
  • During video- EEG monitoring , open-close eyes tests and intermittent photic stimulation (IPS) under different eyes conditions were carried out in epilepsy patients . (bvsalud.org)
  • Photosensitivity is usually tested by intermittent photic stimulation. (semanticscholar.org)
  • Mundy-Castle , A. C.: An analysis of central responses to photic stimulation in normal adults. (springer.com)
  • Abnormal EEG responses to photic stimulation in schizophrenic patients. (escholarship.org)
  • Kikuchi M, Wada Y, Koshino Y . Differences in EEG harmonic driving responses to photic stimulation between normal aging and Alzheimer's disease . (alzforum.org)
  • Hyperventilation and photic stimulation were performed. (bio.net)
  • Hyperventilation and photic stimulation (exposure to rapid flashing lights) are often performed during the EEG. (epilepsy.com)
  • Melatonin secretion from mammalian pineal glands is regulated by light stimulation by means of a complex neuroanatomical pathway that includes the retina, hypothalamic suprachiasmatic nucleus, intermediolateral nucleus of the thoracic spinal cord, and finally, the superior cervical ganglia. (conicyt.cl)
  • PURPOSE: Assessment of a novel method of retinal stimulation, known as suprachoroidal-transretinal stimulation (STS), which was designed to minimize insult to the retina by implantation of stimulating electrodes for artificial vision. (biomedsearch.com)
  • CONCLUSIONS: STS is less invasive in the retina than stimulation through epiretinal or subretinal implants. (biomedsearch.com)
  • Previous in vivo experiments have indicated that impaired parts of the retinal network can be bypassed by electrical stimulation to the retina by microelectrode arrays implanted in the eye. (arvojournals.org)
  • 6 7 14 The other is epiretinal stimulation (ERS), in which retinal ganglion cells (RGCs) and their axons are stimulated with a multielectrode array attached to the vitreous side of the retina. (arvojournals.org)
  • The electroretinogram (ERG) is an electrical response of the retina to photic stimulation. (utah.edu)
  • Hello everybody, I'm a Msc student, I am trying to implement the extracellular stimulation and recording on a model for retina network. (yale.edu)
  • Photic stimulation in symmetric driving response but no epileptiform discharges. (medhelp.org)
  • It is suggested that seizures in photosensitive epilepsy are the result of discharges arising from abnormally activated,by photic stimuli, non-specific thalamic system and impinging upon a hypersensitive occipital cortex. (aston.ac.uk)
  • In humans, evidence for melanopsin involvement in light-driven cognitive stimulation remains indirect, due to the difficulty to selectively isolate its contribution. (pnas.org)
  • A ) Mean increase in primary arterial diameter to flicker stimulation in humans measured with the retinal vessel analyzer (RVA). (nih.gov)
  • The characteristics of the negative occipital spike show striking similarities to those of the recruiting response evoked by electrical stimulation of the non-specific thalamic nuclei as described by other authors. (aston.ac.uk)
  • Chronic subcortical electrode implant in a laboratory rat used to deliver electrical stimulation to the brain. (wikipedia.org)
  • This thesis is the result of an attempt to find means of diagnostic value and understand the underlying mechanisms of photosensitive epilepsy which is a variety of epilepsy where seizures are provoked by photic stimuli. (aston.ac.uk)
  • An experimental study of the mechanism of photic activation in idiopathic epilepsy. (springer.com)
  • Melsen , S.: The value of photic stimulation in the diagnosis of epilepsy. (springer.com)
  • Stevens , J.: Sensory stimulation in centrencephalic and focal cortical epilepsy. (springer.com)
  • IPS is often used in conjunction with other controllable generators of visual stimuli, such as low-level visual stimulation LLVS. (wikipedia.org)
  • A photic sneeze reflex is a sneeze caused by stimuli unrelated to the nose. (reference.com)
  • Combined with our previous observation in the drug-free schizophrenia patients who had lower EEG photic driving, present results supported the hypothesis that the amount of EEG alpha activity, particularly its synchronization to the external stimuli, could reflect the thalamic function in sensory information processing in schizophrenia. (escholarship.org)
  • Periodic photic stimuli across the entire electroencephalographic (EEG) frequency range were used in an attempt to assess EEG functional differences between chronic schizophrenic patients and control subjects. (escholarship.org)
  • The EEG responses to these photic stimuli were significantly attenuated in the schizophrenic patients, specifically at the frequencies within the EEG alpha range. (escholarship.org)
  • We replicated the resting EEG spectral differences between these groups and observed significant differences in periodic photic stimuli on the EEG spectra. (escholarship.org)
  • Brain responses are evoked by known deterministic inputs (experimentally controlled stimuli) that embody designed changes in sensory stimulation or cognitive set. (scholarpedia.org)
  • The purpose of this clinical trial is to examine the effect of non-invasive cortical activation by specific patterned auditory stimulation (Mozart K448- Piano Sonata for Two Hands in D Major), in altering or eliminating photoparoxysmal abnormalities. (clinicaltrials.gov)
  • We will investigate the effect of specific musical stimulation (Mozart K448) to reduce or prevent photoparoxysmal abnormalities in subjects. (clinicaltrials.gov)
  • EEG alpha photic driving abnormalities in chronic schizophrenia. (escholarship.org)
  • This study was intended to examine variations in electroencephalographic (EEG) complexity in response to photic stimulation (PS) during aging to test the hypothesis that the aging process reduces physiologic complexity and functional responsiveness. (nih.gov)
  • Electroencephalographic photic driving in patients with schizophrenia and depression. (escholarship.org)
  • Scientific evidence suggests that shadow flicker does not pose a risk for eliciting seizures as a result of photic stimulation. (evwind.es)
  • The recorded EEG data will be analyzed to determine significant causal reductions or prevention of photoparoxysmal responses resulting from the auditory stimulation, along with determining all induced patterns of cortical activation. (clinicaltrials.gov)
  • Scoville , W. B.: Observations on consciousness and seizure formation following stimulation of septal and uncal areas in man. (springer.com)
  • STS can generate focal excitation in retinal ganglion cells in normal animals and in those with degenerated photoreceptors, which suggests that this method of retinal stimulation is suitable for artificial vision. (biomedsearch.com)
  • Photic stimulation dilates retinal arterioles producing blood flow increases, a response termed functional hyperemia. (nih.gov)
  • One is subretinal stimulation (SRS), in which a sheet containing a microphotodiode array is inserted into the subretinal space to compensate for lost photoreceptor function and stimulate the outer retinal network. (arvojournals.org)
  • All these results indicate that the levels of VIP, GRP, and NPY are mainly regulated by light stimulation and suggest that peptides in the ventrolateral SCN are involved in the mediation of photic information to the pacemaker. (jneurosci.org)
  • Electroencephalogram demonstrating polyspike and wave response produced by photic stimulation. (medscape.com)
  • Neuroscience] Entrainment Through Photic Stimulation? (bio.net)
  • This is called "Photic Driving", which is another word for brainwave entrainment using photic (light) stimulation. (project-meditation.org)
  • In 1942 Dempsey and Morison discovered that repetitive tactile stimulation could also produce entrainment and in 1959, Dr. Chatrian observed auditory entrainment in response to clicks at a frequency of 15 per second. (project-meditation.org)
  • We analyzed stimulation parameters at electrode level as well as distributed metric estimates from an ultra-high spatial resolution magnetic resonance imaging (MRI)-derived finite element human head model and compared them to existing safety limits. (frontiersin.org)
  • In this study, we will use MEG to study the response of brain to a dynamic photic stimulation that has been recently shown to possess great potential as therapeutic approach due to its ability to entrain brain oscillations. (ntu.edu.sg)
  • Factors influencing the psychophysical response such as age, frequency of stimulation are taken into consideration. (ntu.edu.sg)
  • Similarly, asymmetries in the amplitude of the response to photic stimulation alone are not reliable indicators of pathology. (medscape.com)
  • Finally, test its response to extracellular stimulation. (yale.edu)
  • Interestingly, there is an alternative application form of ACS specifically targeting α-oscillations in the visual cortex via periorbital electrodes (retinofugal alternating current stimulation, rACS). (frontiersin.org)
  • METHODS: To investigate if this structure processes emotional information, and whether it depends on motor demands, we recorded subthalamic local field potentials in 16 patients with Parkinson's disease using deep brain stimulation electrodes. (mendeley.com)
  • EEG analysis during photic stimulation demonstrated that the patients had significantly lower coherence irrespective of the stimulus frequency. (medscape.com)
  • Thus, patients with AD may have an impairment of interhemispheric functional connectivity in both nonstimulus and stimulus conditions, which suggests a failure of normal stimulation-related brain activation in AD. (medscape.com)
  • 15%). In comparison with the nonresponders, clozapine responders had a significantly greater increase in photic driving in the electroencephalogram (EEG), primarily in the low-frequency range of alpha band (7.2 hertz [Hz], 8.3 Hz, 9.0 Hz, and 9.6 Hz, but not 12.0 Hz). (escholarship.org)
  • Effects of sedation, stimulation, and placebo on cerebral blood oxygenation. (mpg.de)
  • The effect of acetazolamide on regional cerebral blood oxygenation at rest and under stimulation as assessed by MRI. (mpg.de)
  • These findings confirm the specific involvement of the STN in emotional processes in human, which may underlie the behavioural changes observed in patients with deep brain stimulation. (mendeley.com)
  • In 1984, Dr. Brockopp analyzed audio-visual brain stimulation and in particular hemispheric synchronization during EEG monitoring. (project-meditation.org)
  • Our results emphasize the critical role of light for cognitive brain responses and are, to date, the strongest evidence in favor of a cognitive role for melanopsin, which may confer a form of "photic memory" to human cognitive brain function. (pnas.org)
  • Hammond, 2000) can help depression and that auditory and visual stimulation can help cognitive abilities in children with learning disabilities (e.g. (psychologytoday.com)
  • The central effects of rhythmic sensory stimulation. (springer.com)
  • The purpose of this study was to analyze the changes in the pinealocytes and the blood vessel density of the pineal gland after eliminating photic stimulation in rats. (conicyt.cl)
  • These results give an indirect evidence of the effect that photic stimulation suppression has in the pineal gland in rats. (conicyt.cl)
  • Electrophysiological studies of the feasibility of suprachoroidal-transretinal stimulation for artificial vision in normal and RCS rats. (biomedsearch.com)
  • Here we used somatosensory stimulation in rats to determine age-related parameters of the blood oxygenation level-dependent (BOLD) signal from its apparent inception on postnatal day 13 to adulthood. (nature.com)
  • Figure 1: Age-dependent trends in BOLD fMRI responses to forepaw stimulation in isoflurane-anesthetized rats. (nature.com)
  • band power of the background EEG activity during 1 s light stimulation were investigated in 10 normal human subjects. (eurekamag.com)
  • Myoclonus can occur when an affected person is at rest, and it is made worse by motion, excitement, or flashing light (photic stimulation). (medlineplus.gov)
  • Much in the news today is photic headshaking - headshaking triggered by strong light. (equisearch.com)
  • In horses with a history of light-triggered headshaking, photic stimulation must be No. 1 on the diagnosis list. (equisearch.com)
  • Photic stimulation may also be used to elicit myoclonus, especially cortical reflex myoclonus when present in photo-sensitive forms. (wikipedia.org)
  • Subjects will receive auditory stimulation by exposure to Mozart's Sonata for Two Pianos in D Major, K448. (clinicaltrials.gov)
  • Subjects will receive auditory stimulation by exposure to Beethoven's Für Elise. (clinicaltrials.gov)
  • Subject's will not receive an intervention and will therefore, not receive auditory stimulation and/or exposure to music. (clinicaltrials.gov)
  • There has been considerable interest in the potential of auditory beat stimulation to affect cognition and mood states. (psychologytoday.com)
  • These neurovascular coupling mechanisms include neuronal stimulation of glial cells, leading to the release of vasoactive arachidonic acid metabolites onto blood vessels, release of potassium from glial cells onto vessels, and production and release of nitric oxide (NO), lactate, and adenosine from neurons and glia. (nih.gov)
  • In comparison to tACS, retinofugal stimulation of the visual cortex provides an anatomically circumscribed model to systematically study the mechanisms of action of ACS. (frontiersin.org)
  • rACS affects the well-defined retinofugal pathway ( Rager and Singer, 1998 ) for stimulation confined to the visual system. (frontiersin.org)
  • This makes use of sound stimulation safer than visual or combined audio/visual stimulation. (psychologytoday.com)
  • Shades of gray matter: Non-invasive optical images of human brain responses during visual stimulation. (springer.com)
  • Decrease of glucose in the human visual cortex during photic stimulation. (mpg.de)
  • Methods Eleven DMGP subjects underwent simultaneous EEG and EGG testing while grading the severity of nausea following 30-minute intervals of: (1) baseline, (2) visual stimulation (VS) to provoke more nausea, (3) active VS together with TEA, and (4) TEA alone, and a final 15-minute recording without any intervention. (elsevier.com)
  • Anesthesiologist M.S. Sadove, MD, used photic stimulation to reduce the amount of anesthesia needed for surgery . (project-meditation.org)
  • Age-related variation in EEG complexity to photic stimulation: a multiscale entropy analysis. (nih.gov)
  • Dr. Norman Shealy later confirmed the effect, finding that photic stimulation produced synchronization in more than 5,000 patients. (project-meditation.org)
  • Make sure the model has the anatomical and biophysical properties that you want, and that it responds to injected current or synaptic input or "illumination" in the way that you want (how are you going to represent the effect of photic stimulation? (yale.edu)
  • These findings suggested that EEG photic driving might be more sensitive than the resting EEG in detecting the central nervous system drug effect. (escholarship.org)
  • The frequency of Ca 2+ transients in individual cells increases during flicker stimulation. (nih.gov)
  • Clozapine increases EEG photic driving in clinical responders. (escholarship.org)
  • A significant difference was found between the groups both at rest and following photic stimulation in EEG activity. (escholarship.org)
  • The EEG activity following the photic driving also differentiated the groups. (escholarship.org)