6.2.2 How The Brain Processes Visual Information 3 Flashcards
Unlike simple cells, ____ ____, located in areas V1 and V2, do not respond to the exact location of a stimulus. A complex cell responds to a pattern of light in a particular orientation anywhere with in its large receptive field.
complex cells
A cell that responds to a stimulus in only one ____ is a simple cell. One that responds equally throughout a large area is a complex cell.
location
____, or hypercomplex, cells resemble complex cells with one exception: an end-stopped cell has a strong inhibitory area at one end of its bar-shaped receptive field.
End-stopped
The ____ cell responds to a bar-shaped pattern of light anywhere in it’s broad receptive field, provided that the bar does not extend beyond a certain point.
hypercomplex
Cells having similar properties are grouped together in the visual cortex in ____ perpendicular to the surface. For example, cells within a given column might respond to only the left eye, only the right eye, or both eyes equally.
columns
Given that neurons in area V1 respond strongly too bar- or edge-shaped patterns, we might suppose that the activity of such a cell is the perception of a bar, line, or edge. That is, such cells might be ____ ____ – neurons whose responses indicate the presence of a particular feature.
feature detectors
Supporting the idea of feature detectors is the fact that prolonged exposure to a given visual feature decreases sensitivity to that feature, as if it ____ the relevant detectors.
fatigued
Most cortical neurons respond best to a particular spatial frequency and hardy at all to other frequencies. Most visual researchers therefore believe that neurons in the area V1 detect ____ ____ rather than bars or edges.
spatial frequencies
For mathematical standpoint, ____ ____ frequencies are easy to work with. A branch of mathematics called Fourier analysis demonstrates that a combination of sine waves can produce an unlimited variety of other patterns.
sine wave
Therefore, a series of special frequency ____, some sensitive to horizontal patterns and others to vertical patterns, could represent any possible display.
detectors
____ input is stimulation from both eyes.
Binocular
If an experiment to sutures one eyelet shut for a kittens first 4 to 6 weeks of life, thus depriving it of ____ ____, synapses in the visual cortex gradually become unresponsive to input from the deprived eye. After the deprived eye is opened, the kitten does not respond to it.
actual experience
Binocular vision: light from a point in the visual field strikes points in each retina. Those two areas send axons to separate layers of the lateral geniculate, which in turn sends axons to a single cell in the visual cortex, where input from both eyes ____ onto a single neuron.
converges
When just one eye is open, the synapses from the open eye inhibit synapses from the closed one. If neither eye is active, no axon _____ any other.
outcompetes
If the eyes remain shut still longer, the cortical responses start to become ____ and lose their well-defined receptive fields.
sluggish