visual system

The modern science of cognitive neuropsychology emerged during the 1960s. However there have been a series of influential studies during the last two centuries which have been critical in laying the foundations for studying brain impairment with a view to understanding normal psychological function. The case of Phineas Gage is one of the earliest examples where a specific brain injury gave clues to the function of a particular brain area. Gage obtained his injury after an accident during the construction of part of a railroad in 1848 ...

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Cognitive neuropsychology, Cognitive neuropsychology - History, Cognitive neuropsychology - Methods

Read more here: » Cognitive neuropsychology: Encyclopedia II - Cognitive neuropsychology - History

Visual perception is one of the senses, consisting of the ability to detect light and interpret (see) it as the perception known as sight or naked eye vision. Vision has a specific sensory system, the visual system. There is disagreement as to whether or not this constitutes one, two or even three distinct senses. Some people make a distinction between "black and white" vision and the perception of colour, and others point out that vision using rod cells uses different physical detectors on the retina from ...

Including:

• Visual perception - The visual system
• Visual perception - Sources of information
• Visual perception - Individual and group differences in visual perception
• Visual perception - Theoretical perspectives in the study of visual perception
• Visual perception - Unconscious inference
• Visual perception - Gestalt
• Visual perception - Ecological psychology
• Visual perception - Types of visual perception
• Visual perception - Disorders/Dysfuntions

Read more here: » Visual perception: Encyclopedia - Visual perception

The term brain implants, also known as neural implants, usually refers to devices of a technological nature that are connected directly to a biological subject's brain - usually placed on the surface of the brain, or attached to the brain's cortex. A common purpose of modern brain implants and the focus of much current research is establishing a biomedical prosthesis circumventing areas in the brain, which became dysfunctional after a stroke or other head injuries. This includes sensory substitution, e.g. in vision. Brain implants inv ...

Including:

• Brain implant - Research
• Brain implant - Historical research on brain implants
• Brain implant - Ethical considerations
• Brain implant - Brain implants in fiction and philosophy
• Brain implant - Further Readings

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The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments" (J. Smythies [1]), while field of view "refers to the physical objects and light sources in the external world that impinge the retina". In other words, field of view is everything that (at a given time) causes light to fall onto the retina. This input is processed by the visual sys ...

Including:

• Visual field - Visual field loss

Read more here: » Visual field: Encyclopedia - Visual field

Vision therapy, also known as visual therapy or visual training, is a broadly-defined set of treatment programs related to the improvement of visual health and comfort. Probably, the best known form of vision therapy is orthoptics which treats binocular vision disorders such as amblyopia, strabismus, and double vision or diplopia. Other problems treated with vision therapy include difficulties of visual attention and concentration, which are said to manifest as an inability to sustain focus or to shift focus from one are ...

Including:

• Vision therapy - History
• Vision therapy - Scientific support for vision therapy
• Vision therapy - Skepticism
• Vision therapy - See Also

Read more here: » Vision therapy: Encyclopedia - Vision therapy

The scientific method or scientific process is fundamental to scientific investigation and to the acquisition of new knowledge based upon physical evidence by the scientific community. Scientists use observations and reasoning to propose tentative explanations for phenomena, termed hypotheses. Under the working assumption of methodological materialism, observable events in the natural world (including the artificial works of humanity) are explained only by natural causes without assuming the existence or non-existence of the su ...

Including:

• Scientific method - Elements of scientific method
• Scientific method - Characterizations
• Scientific method - Hypotheses development
• Scientific method - Predictions from the hypotheses
• Scientific method - Experiments
• Scientific method - Evaluations and iterations
• Scientific method - Testing and improvements
• Scientific method - Confirmations
• Scientific method - Scope and goals
• Scientific method - Scientific communities
• Scientific method - Peer review evaluations
• Scientific method - Reproduction and record-keeping
• Scientific method - History
• Scientific method - Philosophical issues
• Scientific method - Scientific method and the practice of science
• Scientific method - Formal approaches
• Scientific method - Quotations
• Scientific method - Notes
• Scientific method - Historical references to scientific method

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In animals, the brain, or encephalon (Greek for "in the head"), acts as the control center of the central nervous system. In most animals, the brain is located in the head close to the primary sensory apparatus and the mouth. While all vertebrate nervous systems have a brain, invertebrate nervous systems may have either a centralized brain or collections of individual ganglia. The brain is an extremely complex organ; for example, the human brain is a collection of 100 billion neurons, each linked with up to 25,000 others [1]. T ...

Including:

• Brain - Mind and brain
• Brain - History
• Brain - Modern neuroscience
• Brain - Comparative anatomy
• Brain - Invertebrates
• Brain - Vertebrates
• Brain - Neurobiology
• Brain - Histology
• Brain - Function
• Brain - Brain pathology
• Brain - The study of the brain
• Brain - Fields of study
• Brain - Methods of observation
• Brain - Other matters
• Brain - Brain as food

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Beauty is the phenomenon of the experience of pleasure, through the perception of balance and proportion of stimulus. It involves the cognition of a balanced form and structure that elicits attraction and appeal towards a person, animal, inanimate object, scene, music, or idea. The opposite of beauty is ugliness, the experience of displeasure at some stimulus. Beauty - Beauty and aesthetics. Understanding the nature and meaning of beauty is one of the key themes in the philosophical discipline known as aest ...

Including:

• Beauty - Beauty and aesthetics
• Beauty - Theories of beauty
• Beauty - Mathematical Beauty
• Beauty - Effects of beauty in human society

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Vision may mean: Visual perception via the visual system, one of the senses. Vision (religion), inspirational renderings believed to come from a deity. In management, a route to a goal. An imagined picture originating with not-so-divine sources: politicians, business planners and change gurus play on this sense of the word. Vision statement, A corporate long-term goal - not to be confused with a mission statement (extending the religious metaphor). Vision (IRC), BeOS's leading

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Cognitive neuropsychology is a branch of neuropsychology that aims to understand how the structure and function of the brain relates to specific psychological processes. It places a particular emphasis on studying the cognitive effects of brain injury or neurological illness with a view to inferring models of normal cognitive functioning. Cognitive neuropsychology - History. The modern science of cognitive neuropsychology emerged during the 1960s. However there have been a series of inf ...

Including:

• Cognitive neuropsychology - History
• Cognitive neuropsychology - Methods

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List of regions in the human brain - Rhombencephalon hindbrain. medulla oblongata medullary pyramids pons fourth ventricle cerebellum cerebellar vermis cerebellar hemispheres anterior lobe posterior lobe flocculonodular lobe cerebellar nuclei

In 1988, a review of 238 scienfitic articals was published in the Journal of the American Optometric Association defining vision therapy as "a clinical approach for correcting and ameliorating the effects of eye movement disorders, non-strabismic binocular dysfunctions, focusing disorders, strabismus, amblyopia, nystagmus, and certain visual perceptual (information processing) disorders." The paper contains the concluding statement, "It is evident from the research that there is scientific support for the efficacy of vision therapy in ...

See also:

Vision therapy, Vision therapy - History, Vision therapy - Scientific support for vision therapy, Vision therapy - Skepticism, Vision therapy - See Also

Read more here: » Vision therapy: Encyclopedia II - Vision therapy - Scientific support for vision therapy

The opponent color theory was first proposed by Ewald Hering in 1872 (Hering, 1964). He thought that the colors red, yellow, green, and blue are special in that any other color can be described as a mix of them, and that they exist in opposite pairs. That is, either red or green is perceived and never greenish-red. (Note that although yellow is a mixture of red and green in the RGB color theory, the eye does not perceive it as such.) In 1957 Leo Hurvich and Dorothea Jameson provided quantitative data for Hering's co ...

See also:

Opponent process, Opponent process - History

Read more here: » Opponent process: Encyclopedia II - Opponent process - History

Phototransduction is the wonderfully complex process whereby the energy of a photon is used to change the inherent membrane potential of the photoreceptor -- and thereby signal to the nervous system that light is in the visual field. Photoreceptor - Dark Current. Unstimulated (in the dark), the voltage-gated sodium channels in the outer segment are open because cyclic GMP (cGMP) is bound to them. This means that sodium ions (and therefore positive charge) are entering the photoreceptor, depolarizing it to about -40 mV (resting potential is usually -65 mV). This d ...

See also:

Photoreceptor, Photoreceptor - Structure, Photoreceptor - Humans, Photoreceptor - Phototransduction, Photoreceptor - Dark Current, Photoreceptor - Signal Transduction Pathway, Photoreceptor - Advantages, Photoreceptor - Function, Photoreceptor - Signaling

Read more here: » Photoreceptor: Encyclopedia II - Photoreceptor - Phototransduction

Three groups of animals, with some exceptions, have notably complex brains: the arthropods (insects and crustaceans), the cephalopods (octopuses, squid, and similar mollusks), and the craniates (vertebrates)[6]. The brain of arthropods and cephalopods arises from twin parallel nerve cords that extend through the body of the animal. In arthropods, the brain consists of a central brain with three divisions and large optical lobes behind each eye for visual processing^{See also:}

Brain, Brain - Mind and brain, Brain - History, Brain - Modern neuroscience, Brain - Comparative anatomy, Brain - Invertebrates, Brain - Vertebrates, Brain - Humans, Brain - Neurobiology, Brain - Histology, Brain - Function, Brain - Brain pathology, Brain - The study of the brain, Brain - Fields of study, Brain - Methods of observation, Brain - Other matters, Brain - Brain as food

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Activation of a photoreceptor cell is actually a hyperpolarization; when they are not being stimulated, rods and cones depolarize and release a neurotransmitter spontaneously, and activation of photopigments by light sends a signal by preventing this. Depolarization occurs due to the fact that in the dark, cells have a relatively high concentration of cyclic guanosine 3'-5' monophosphate (cGMP), which opens ion channels (largely sodium channels, though Calcium can enter through these channels as well). The positive charges of the ions that e ...

See also:

Rod cell, Rod cell - Response to light, Rod cell - Table, Rod cell - Reference

Read more here: » Rod cell: Encyclopedia II - Rod cell - Response to light

In the somatosensory system, receptive fields are regions of the skin or of internal organs. Some types of mechanoreceptors have large receptive fields, while others have smaller ones. Large receptive fields allow the cell to detect changes over a wider area, but lead to a less precise perception. Thus, the fingers, which require the ability to detect fine detail, have many, densely packed mechanoreceptors with small receptive fields, while the back and legs, for example, have fewer receptors with large receptive fields. Receptors wit ...

See also:

Receptive field, Receptive field - Somatosensory system, Receptive field - Auditory system, Receptive field - Visual system, Receptive field - Retinal ganglion cells, Receptive field - Lateral geniculate nucleus, Receptive field - Visual cortex, Receptive field - Extrastriate visual areas

Read more here: » Receptive field: Encyclopedia II - Receptive field - Somatosensory system

Phototransduction is the complex process whereby the energy of a photon is used to change the inherent membrane potential of the photoreceptor -- and thereby signal to the nervous system that light is in the visual field. Photoreceptor - Dark Current. Unstimulated (in the dark), the voltage-gated sodium channels in the outer segment are open because cyclic GMP (cGMP) is bound to them. This means that sodium ions (and therefore positive charge) are entering the photoreceptor, depolarizing it to about -40 mV (resting potential is usually -65 mV). This d ...

See also:

Photoreceptor, Photoreceptor - Structure, Photoreceptor - Humans, Photoreceptor - Phototransduction, Photoreceptor - Dark Current, Photoreceptor - Signal Transduction Pathway, Photoreceptor - Advantages, Photoreceptor - Function, Photoreceptor - Signaling

Read more here: » Photoreceptor: Encyclopedia II - Photoreceptor - Phototransduction

The opponent colour theory was first proposed by Ewald Hering in 1872 (Hering, 1964). He thought that the colours red, yellow, green, and blue are special in that any other colour can be described as a mix of them, and that they exist in opposite pairs. That is, either red or green is perceived and never greenish-red. (Note that although yellow is a mixture of red and green in the RGB color theory, the eye does not perceive it as such.) In 1957 Leo Hurvich and Dorothea Jameson provided quantitative data for Hering's col ...

See also:

Opponent process, Opponent process - History, Opponent process - Reddish green and yellowish blue

Read more here: » Opponent process: Encyclopedia II - Opponent process - History

There are many stimulus modalities: temperature, taste, sound, and pressure. The type of sensory receptor activated by a stimulus plays the primary role in coding the stimulus modality. In the memory-prediction framework, Jeff Hawkins mentions a correspondence between the six layers of the cerebral cortex and the six layers of the optic tract of the visual system. The primary visual cortex has areas labelled V1, V2, V3, V4, V5, MT, IT, etc. Hawkins then lays out a scheme for the analogous modalities of the sensory system. In particular, there will be cells which can be labelled as belonging to V1, V2 A1, A2, etc.:

See also:

Sensory system, Sensory system - Modality, Sensory system - V1, Sensory system - A1, Sensory system - S1, Sensory system - G1, Sensory system - O1, Sensory system - Human sensory system

Read more here: » Sensory system: Encyclopedia II - Sensory system - Modality