Visual Cortex: Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.Visual Pathways: Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.Evoked Potentials, Visual: The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Visual Fields: The total area or space visible in a person's peripheral vision with the eye looking straightforward.Cerebral Cortex: The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Visual Acuity: Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.Cats: 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)Sensory Deprivation: The absence or restriction of the usual external sensory stimuli to which the individual responds.Dominance, Ocular: The functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.Prefrontal Cortex: The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.Pattern Recognition, Visual: Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.Geniculate Bodies: Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.Vision, Monocular: Images seen by one eye.Neurons: 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.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Orientation: Awareness of oneself in relation to time, place and person.Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Auditory Cortex: The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.Vision, Ocular: The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.Motor Cortex: 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.Somatosensory Cortex: Area of the parietal lobe concerned with receiving sensations such as movement, pain, pressure, position, temperature, touch, and vibration. It lies posterior to the central sulcus.Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Reaction Time: The time from the onset of a stimulus until a response is observed.Contrast Sensitivity: The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.Macaca: A genus of the subfamily CERCOPITHECINAE, family CERCOPITHECIDAE, consisting of 16 species inhabiting forests of Africa, Asia, and the islands of Borneo, Philippines, and Celebes.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Space Perception: The awareness of the spatial properties of objects; includes physical space.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Motion Perception: The real or apparent movement of objects through the visual field.Phosphenes: A subjective visual sensation with the eyes closed and in the absence of light. Phosphenes can be spontaneous, or induced by chemical, electrical, or mechanical (pressure) stimuli which cause the visual field to light up without optical inputs.Vision, Binocular: The blending of separate images seen by each eye into one composite image.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Ferrets: Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Nerve Net: A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Psychophysics: The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.Macaca mulatta: A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.Macaca fascicularis: A species of the genus MACACA which typically lives near the coast in tidal creeks and mangrove swamps primarily on the islands of the Malay peninsula.Fixation, Ocular: The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.Ocular Physiological Phenomena: Processes and properties of the EYE as a whole or of any of its parts.Occipital Lobe: 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.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Form Perception: The sensory discrimination of a pattern shape or outline.Blindness: The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.Parietal Lobe: Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.Darkness: The absence of light.Eye Movements: Voluntary or reflex-controlled movements of the eye.Discrimination (Psychology): Differential response to different stimuli.Dominance, Cerebral: Dominance of one cerebral hemisphere over the other in cerebral functions.Visual Field Tests: Method of measuring and mapping the scope of vision, from central to peripheral of each eye.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Temporal Lobe: Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the OCCIPITAL LOBE.Vision Disorders: Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132).Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Electroencephalography: 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.Synapses: Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.Entorhinal Cortex: Cerebral cortex region on the medial aspect of the PARAHIPPOCAMPAL GYRUS, immediately caudal to the OLFACTORY CORTEX of the uncus. The entorhinal cortex is the origin of the major neural fiber system afferent to the HIPPOCAMPAL FORMATION, the so-called PERFORANT PATHWAY.Pulvinar: Large mass of nuclei forming the most caudal portion of the THALAMUS and overhanging the GENICULATE BODIES and the dorsolateral surface of the MIDBRAIN. It is divided into four parts: the lateral, medial, inferior, and oral pulvinar nuclei.Electrophysiology: 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.Sensory Thresholds: The minimum amount of stimulus energy necessary to elicit a sensory response.Depth Perception: Perception of three-dimensionality.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Galago: A genus of the family Lorisidae having four species which inhabit the forests and bush regions of Africa south of the Sahara and some nearby islands. The four species are G. alleni, G. crassicaudatus, G. demidovii, and G. senegalensis. There is another genus, Euoticus, containing two species which some authors have included in the Galago genus.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Superior Colliculi: The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Frontal Lobe: The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus.Illusions: The misinterpretation of a real external, sensory experience.Microelectrodes: Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)Kidney Cortex: The outer zone of the KIDNEY, beneath the capsule, consisting of KIDNEY GLOMERULUS; KIDNEY TUBULES, DISTAL; and KIDNEY TUBULES, PROXIMAL.Transcranial Magnetic Stimulation: 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.Eye Enucleation: The surgical removal of the eyeball leaving the eye muscles and remaining orbital contents intact.Amblyopia: A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.Parvalbumins: Low molecular weight, calcium binding muscle proteins. Their physiological function is possibly related to the contractile process.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Vision Disparity: The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye.Scotoma: A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.Magnetoencephalography: The measurement of magnetic fields over the head generated by electric currents in the brain. As in any electrical conductor, electric fields in the brain are accompanied by orthogonal magnetic fields. The measurement of these fields provides information about the localization of brain activity which is complementary to that provided by ELECTROENCEPHALOGRAPHY. Magnetoencephalography may be used alone or together with electroencephalography, for measurement of spontaneous or evoked activity, and for research or clinical purposes.Pyramidal Cells: Projection neurons in the CEREBRAL CORTEX and the HIPPOCAMPUS. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.Evoked Potentials: 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.Hemianopsia: Partial or complete loss of vision in one half of the visual field(s) of one or both eyes. Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. Quadrantanopsia refers to loss of vision in one quarter of the visual field in one or both eyes.Optical Illusions: An illusion of vision usually affecting spatial relations.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.Cerebellar Cortex: The superficial GRAY MATTER of the CEREBELLUM. It consists of two main layers, the stratum moleculare and the stratum granulosum.Saccades: An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.Nonlinear Dynamics: The study of systems which respond disproportionately (nonlinearly) to initial conditions or perturbing stimuli. Nonlinear systems may exhibit "chaos" which is classically characterized as sensitive dependence on initial conditions. Chaotic systems, while distinguished from more ordered periodic systems, are not random. When their behavior over time is appropriately displayed (in "phase space"), constraints are evident which are described by "strange attractors". Phase space representations of chaotic systems, or strange attractors, usually reveal fractal (FRACTALS) self-similarity across time scales. Natural, including biological, systems often display nonlinear dynamics and chaos.Animals, Newborn: Refers to animals in the period of time just after birth.Electrodes, Implanted: Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.Adaptation, Physiological: The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.Color Perception: Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.Thalamus: Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.Synaptic Transmission: 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.Face: The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.Tupaiidae: The only family of the order SCANDENTIA, variously included in the order Insectivora or in the order Primates, and often in the order Microscelidea, consisting of five genera. They are TUPAIA, Ananthana (Indian tree shrew), Dendrogale (small smooth-tailed tree shrew), Urogale (Mindanao tree shrew), and Ptilocercus (pen-tailed tree shrew). The tree shrews inhabit the forest areas of eastern Asia from India and southwestern China to Borneo and the Philippines.Strabismus: Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)Haplorhini: A suborder of PRIMATES consisting of six families: CEBIDAE (some New World monkeys), ATELIDAE (some New World monkeys), CERCOPITHECIDAE (Old World monkeys), HYLOBATIDAE (gibbons and siamangs), CALLITRICHINAE (marmosets and tamarins), and HOMINIDAE (humans and great apes).Cortical Synchronization: EEG phase synchronization of the cortical brain region (CEREBRAL CORTEX).gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Touch: Sensation of making physical contact with objects, animate or inanimate. Tactile stimuli are detected by MECHANORECEPTORS in the skin and mucous membranes.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.Discrimination Learning: Learning that is manifested in the ability to respond differentially to various stimuli.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Dendrites: Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.Voltage-Sensitive Dye Imaging: Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Excitatory Postsynaptic Potentials: Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS.Blindness, Cortical: Total loss of vision in all or part of the visual field due to bilateral OCCIPITAL LOBE (i.e., VISUAL CORTEX) damage or dysfunction. Anton syndrome is characterized by the psychic denial of true, organic cortical blindness. (Adams et al., Principles of Neurology, 6th ed, p460)Adrenal Cortex: The outer layer of the adrenal gland. It is derived from MESODERM and comprised of three zones (outer ZONA GLOMERULOSA, middle ZONA FASCICULATA, and inner ZONA RETICULARIS) with each producing various steroids preferentially, such as ALDOSTERONE; HYDROCORTISONE; DEHYDROEPIANDROSTERONE; and ANDROSTENEDIONE. Adrenal cortex function is regulated by pituitary ADRENOCORTICOTROPIN.Fovea Centralis: An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)Brain Waves: Wave-like oscillations of electric potential between parts of the brain recorded by EEG.Calbindin 2: A calbindin protein that is differentially expressed in distinct populations of NEURONS throughout the vertebrate and invertebrate NERVOUS SYSTEM, and modulates intrinsic neuronal excitability and influences LONG-TERM POTENTIATION. It is also found in LUNG, TESTIS, OVARY, KIDNEY, and BREAST, and is expressed in many tumor types found in these tissues. It is often used as an immunohistochemical marker for MESOTHELIOMA.Adaptation, Ocular: The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)Gyrus Cinguli: One of the convolutions on the medial surface of the CEREBRAL HEMISPHERES. It surrounds the rostral part of the brain and CORPUS CALLOSUM and forms part of the LIMBIC SYSTEM.Recognition (Psychology): The knowledge or perception that someone or something present has been previously encountered.Feedback: A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.Memory, Short-Term: Remembrance of information for a few seconds to hours.Callithrix: A genus of the subfamily CALLITRICHINAE occurring in forests of Brazil and Bolivia and containing seventeen species.Perceptual Masking: The interference of one perceptual stimulus with another causing a decrease or lessening in perceptual effectiveness.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.Size Perception: The sensory interpretation of the dimensions of objects.Perceptual Disorders: Cognitive disorders characterized by an impaired ability to perceive the nature of objects or concepts through use of the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory, or sensory stimuli presented from one side of the body.Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Interneurons: Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.Wakefulness: A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.Lighting: The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.Color Vision: Function of the human eye that is used in bright illumination or in daylight (at photopic intensities). Photopic vision is performed by the three types of RETINAL CONE PHOTORECEPTORS with varied peak absorption wavelengths in the color spectrum (from violet to red, 400 - 700 nm).Color: The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Cerebrovascular Circulation: The circulation of blood through the BLOOD VESSELS of the BRAIN.Long-Term Synaptic Depression: A persistent activity-dependent decrease in synaptic efficacy between NEURONS. It typically occurs following repeated low-frequency afferent stimulation, but it can be induced by other methods. Long-term depression appears to play a role in MEMORY.Vibrissae: Stiff hairs projecting from the face around the nose of most mammals, acting as touch receptors.Vision Tests: A series of tests used to assess various functions of the eyes.Optic Chiasm: The X-shaped structure formed by the meeting of the two optic nerves. At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side. As a result each half of the brain receives information about the contralateral visual field from both eyes.Awareness: The act of "taking account" of an object or state of affairs. It does not imply assessment of, nor attention to the qualities or nature of the object.Signal Detection, Psychological: Psychophysical technique that permits the estimation of the bias of the observer as well as detectability of the signal (i.e., stimulus) in any sensory modality. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate: The lectin wheatgerm agglutinin conjugated to the enzyme HORSERADISH PEROXIDASE. It is widely used for tracing neural pathways.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Mice, Inbred C57BLTask Performance and Analysis: The detailed examination of observable activity or behavior associated with the execution or completion of a required function or unit of work.Sensory Aids: Devices that help people with impaired sensory responses.Electrophysiological Phenomena: The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.Saimiri: A genus of the family CEBIDAE consisting of four species: S. boliviensis, S. orstedii (red-backed squirrel monkey), S. sciureus (common squirrel monkey), and S. ustus. They inhabit tropical rain forests in Central and South America. S. sciureus is used extensively in research studies.Thalamic Nuclei: Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.Neurophysiology: The scientific discipline concerned with the physiology of the nervous system.Parahippocampal Gyrus: A convolution on the inferior surface of each cerebral hemisphere, lying between the hippocampal and collateral sulci.Glutamate Decarboxylase: A pyridoxal-phosphate protein that catalyzes the alpha-decarboxylation of L-glutamic acid to form gamma-aminobutyric acid and carbon dioxide. The enzyme is found in bacteria and in invertebrate and vertebrate nervous systems. It is the rate-limiting enzyme in determining GAMMA-AMINOBUTYRIC ACID levels in normal nervous tissues. The brain enzyme also acts on L-cysteate, L-cysteine sulfinate, and L-aspartate. EC Decortication: Partial or total removal, ablation, or destruction of the cerebral cortex; may be chemical. It is not used with animals that do not possess a cortex, i.e., it is used only with mammals.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Rats, Sprague-Dawley: 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.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Axonal Transport: The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)Dark Adaptation: Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.S100 Calcium Binding Protein G: A calbindin protein found in many mammalian tissues, including the UTERUS, PLACENTA, BONE, PITUITARY GLAND, and KIDNEYS. In intestinal ENTEROCYTES it mediates intracellular calcium transport from apical to basolateral membranes via calcium binding at two EF-HAND MOTIFS. Expression is regulated in some tissues by VITAMIN D.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Macaca radiata: A species of macaque monkey that mainly inhabits the forest of southern India. They are also called bonnet macaques or bonnet monkeys.Autoradiography: The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)Consciousness: Sense of awareness of self and of the environment.Retinal Ganglion Cells: Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.Corpus Callosum: Broad plate of dense myelinated fibers that reciprocally interconnect regions of the cortex in all lobes with corresponding regions of the opposite hemisphere. The corpus callosum is located deep in the longitudinal fissure.ReadingLong-Term Potentiation: A persistent increase in synaptic efficacy, usually induced by appropriate activation of the same synapses. The phenomenological properties of long-term potentiation suggest that it may be a cellular mechanism of learning and memory.PrimatesNeocortex: The largest portion of the CEREBRAL CORTEX in which the NEURONS are arranged in six layers in the mammalian brain: molecular, external granular, external pyramidal, internal granular, internal pyramidal and multiform layers.Imagination: A new pattern of perceptual or ideational material derived from past experience.Feedback, Sensory: A mechanism of communicating one's own sensory system information about a task, movement or skill.Electron Transport Complex IV: A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Calbindins: Calcium-binding proteins that are found in DISTAL KIDNEY TUBULES, INTESTINES, BRAIN, and other tissues where they bind, buffer and transport cytoplasmic calcium. Calbindins possess a variable number of EF-HAND MOTIFS which contain calcium-binding sites. Some isoforms are regulated by VITAMIN D.Optic Nerve: The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Motion: Physical motion, i.e., a change in position of a body or subject as a result of an external force. It is distinguished from MOVEMENT, a process resulting from biological activity.Flicker Fusion: The point or frequency at which all flicker of an intermittent light stimulus disappears.Data Interpretation, Statistical: Application of statistical procedures to analyze specific observed or assumed facts from a particular study.Muscimol: A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.Macaca nemestrina: A species of the genus MACACA which inhabits Malaya, Sumatra, and Borneo. It is one of the most arboreal species of Macaca. The tail is short and untwisted.Normal Distribution: Continuous frequency distribution of infinite range. Its properties are as follows: 1, continuous, symmetrical distribution with both tails extending to infinity; 2, arithmetic mean, mode, and median identical; and 3, shape completely determined by the mean and standard deviation.Electrooculography: Recording of the average amplitude of the resting potential arising between the cornea and the retina in light and dark adaptation as the eyes turn a standard distance to the right and the left. The increase in potential with light adaptation is used to evaluate the condition of the retinal pigment epithelium.Field Dependence-Independence: The ability to respond to segments of the perceptual experience rather than to the whole.Touch Perception: The process by which the nature and meaning of tactile stimuli are recognized and interpreted by the brain, such as realizing the characteristics or name of an object being touched.Alpha Rhythm: Brain waves characterized by a relatively high voltage or amplitude and a frequency of 8-13 Hz. They constitute the majority of waves recorded by EEG registering the activity of the parietal and occipital lobes when the individual is awake, but relaxed with the eyes closed.Time Perception: The ability to estimate periods of time lapsed or duration of time.Emotions: Those affective states which can be experienced and have arousing and motivational properties.Behavior: The observable response of a man or animal to a situation.Agnosia: Loss of the ability to comprehend the meaning or recognize the importance of various forms of stimulation that cannot be attributed to impairment of a primary sensory modality. Tactile agnosia is characterized by an inability to perceive the shape and nature of an object by touch alone, despite unimpaired sensation to light touch, position, and other primary sensory modalities.Albinism: General term for a number of inherited defects of amino acid metabolism in which there is a deficiency or absence of pigment in the eyes, skin, or hair.Eye: The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.Iontophoresis: Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.Visual Prosthesis: Artificial device such as an externally-worn camera attached to a stimulator on the RETINA, OPTIC NERVE, or VISUAL CORTEX, intended to restore or amplify vision.