Spatial Vision: From Spots to Stripes Flashcards
complex cell
A neuron whose receptive-field characteristics cannot be easily predicted by mapping with spots of light.
contrast threshold
The smallest amount of contrast required to detect a pattern.
phase
The relative position of a grating.
sine wave grating
A grating with a sinusoidal luminance profile.
cycle
For a grating, a pair consisting of one dark bar and one bright bar.
parvocellular layer
Any of the top four neuron-containing layers of the lateral geniculate nucleus, the cells of which are physically smaller than those in the bottom two layers.
cycles per degree
The number of pairs of dark and bright bars per degree of visual angle.
end stopping
The process by which a cell in the cortex first increases its firing rate as the bar length increases to fill up its receptive field, and then decreases its firing rate as the bar is lengthened further.
ipsilateral
Referring to the same side of the body (or brain).
anisometropia
A condition in which the two eyes have different refractive errors (e.g., one eye is farsighted and the other not).
ocular dominance
The property of the receptive fields of striate cortex neurons by which they demonstrate a preference, responding somewhat more rapidly when a stimulus is presented in one eye than when it is presented in the other.
filter
An acoustic, electrical, electronic, or optical device, instrument, computer program, or neuron that allows the passage of some frequencies or digital elements and blocks the passage of others.
lateral geniculate nucleus (LGN)
A structure in the thalamus, part of the midbrain, that receives input from the retinal ganglion cells and has input and output connections to the visual cortex.
hypercolumn
A 1-millimeter block of striate cortex containing two sets of columns, each covering every possible orientation (0–180 degrees), with one set preferring input from the left eye and one set preferring input from the right eye.
simple cell
A cortical neuron with clearly defined excitatory and inhibitory regions.