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What is the visual field?
The whole area that you can see without moving your head or eyes
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What is visual acuity?
Sharpness of vision.
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What are photoreceptors?
Neural cells in the retina that respond to light
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What is lateral inhibition?
The temporal retina of left eye gets info about right visual field of the right eye. The nasal retina of the right eye gets info about the right visual field of the left eye The phenomenon by which interconnected neurons inhibit their neighbours, producing contrast at the edges of regions.
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What is the cornea?
the transparent outer layer of the eye, whose curvature is fixed. It bends light rays and is primarily responsible for forming the image on the retina.
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What is the lens?
a structure in the eye that helps focus an image on the retina.
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What is refraction?
The idea behind eyeglasses, telescopes and microscopes.The bending of light rays by a change in the density of a medium, such as the cornea and the lens of the eyes.
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What is the cillary muscle?
One of the muscles that controls the shape of the lens inside the eye, focusing an image on the retina.
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What is accomodation?
The process of focusing by the cillary muscles and the lens to form a sharp image on the retina.
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What is the pupil?
The aperture (opening), formed by the iris that allows light to enter the eye.
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What is the iris?
The circular structure of teh eye that provides an opening to form the pupil
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How does the image on the retina appear?
inverted top to bottom, left to right
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What is the optic chasm?
The information is processed on the opposite side of the eye that views it. For example, what is seen on the left is processed by the right eye.
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What is the Lateral Geniculate Nucleus?
The part of the thalamus that recieves info from the optic tract to send it to visual areas of the occipital cortex.
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What is optic radiation?
Axons from the LGN that extend to the VI
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What is the primary cortex (V1) or striate cortex?
A part of the occipital lobe that processes most visual info.
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What is the extrastriate cortex?
The visual cortex outside of the V1. Works in parallel process with the V1 to process different visual aspects. Processes info in a topographic manner.
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What is a scotoma? Why is it called blindsight?
A perceptual gap (blindness) allowing the diagnosis of a defect in the visual pathway or brain. Called blindsight bc cannot identify visual cues but some visual discrimination may be possible.
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What is the receptive field?
The stimulus region and features that affect the activity of a cell in a sensory system.
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What is an on-center bipolar cell?
Light detected in the center of the bipolar cell causes depolarization for more glutamate and then an increased firing rate.
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What is an off center bipolar cell?
Light detected in the off center of the cell causes inhibition by hyperpolarizing the cell and releasing less glutamate and decreasing firing rate.
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What is an on center ganglion cell?
a cell that recieves info and is activated when light is presented to the center of the receptive field.
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What is an off center ganglion cell?
a cell that is activated when light is in the periphery of the receptive field.
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What is an off surround/ on center cell?
A cell that is depolarized when light shines in teh center, hyperpolarized when light shines in the periphery
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What is an on surround/ off center cell?
A cell that is depolarized when light shines in the periphery. hyperpolarization by light in the center.
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What does it mean to say that the outer layers of the LGN are parvocellular ?
It means they are small
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What does it mean to say the inner layers of the LGN are magnocellular?
It means they are large.
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What is a simple cortical cell?
a cell that responds to a bar or edge of a particular orientation or width in a particualr location in teh visual field
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What is a complex cortical cell?
a cell that has a larger visual field and only responds to a bar of a particular orientation or size in a particular area of the visual field.
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What are M ganglion cells?
Cells that respond to rods, project axons to magnocellular layers (consisting of larger cells)
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What are P ganglion cells?
cells that respond to cones, project axons to parvocellular layers (consiting of smaller cells)
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What is ataxia?
An impairment in the direction, extent and rate of muscullar movement
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The primary visual cortex is organized into columns and slabs. What is the ocular dominance column?
A region of the cortex in which one eye or the other provides a greater degree of synaptic output.
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The primary visual cortex is organized into columns and slabs. What is the ocular dominance slab?
A slab of the visual cortex in which neurons of all layers respond preferentially to stimulation of one eye.
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The primary visual cortex is organized into columns and slabs. What is the orientation column?
A column of visual cortex that responds to rod shaped stimuli of a particular orientation.
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What is mirror neuron?
A neuron that is active both when an individual makes a particular movement and when that individual sees another individual makes that same movement
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What is myopia?
Nearsightedness
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