6.2.2 How The Brain Processes Visual Information 3

Question 1

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.

Answer 1

complex cells

Question 2

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.

Answer 2

location

Question 3

____, 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.

Answer 3

End-stopped

Question 4

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.

Answer 4

hypercomplex

Question 5

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.

Answer 5

columns

Question 6

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.

Answer 6

feature detectors

Question 7

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.

Answer 7

fatigued

Question 8

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.

Answer 8

spatial frequencies

Question 9

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.

Answer 9

sine wave

Question 10

Therefore, a series of special frequency ____, some sensitive to horizontal patterns and others to vertical patterns, could represent any possible display.

Answer 10

detectors

Question 11

____ input is stimulation from both eyes.

Answer 11

Binocular

Question 12

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.

Answer 12

actual experience

Question 13

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.

Answer 13

converges

Question 14

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.

Answer 14

outcompetes

Question 15

If the eyes remain shut still longer, the cortical responses start to become ____ and lose their well-defined receptive fields.

Answer 15

sluggish

Question 16

For each aspect of visual experience, researchers identify a ____ ____, when experiences have a particularly strong and enduring influence. The sensitive period ends with the onset of certain chemicals that stabilise synapses and inhabit axonal sprouting.

Answer 16

sensitive period

Question 17

Most neurons in the human visual cortex respond to both eyes – specifically, to approximately corresponding areas of both eyes. By comparing the input from the two eyes, you receive stereoscopic ____ ____.

Answer 17

depth perception

Question 18

Stereoscopic depth perception requires the brain to detect ____ ____, the discrepancy between what the left and the right eyes see.

Answer 18

retinal disparity

Question 19

Certain children are born with ____ (or strabismic amblyopia), aka lazy eye, a condition in which the eyes do not point in the same direction.

Answer 19

strabismus

Question 20

The usual treatment for strabismus is to put a ____ over the active eye, forcing attention to the other one.

Answer 20

patch

Question 21

A promising therapy for lazy eye is to ask a child to play ____ ____ ____ that require attention to both eyes. Good performance requires increasing attention to exactly the kind of input we want to enhance.

Answer 21

action video games

Question 22

About 70% of all infants have ____, a blurring of vision for lines in one direction (e.g., horizontal, vertical, or one of the diagonals), caused by an asymmetric curvature of the eyes. Normal growth reduces the prevalence of astigmatism to about 10% in four year old children.

Answer 22

astigmatism

Question 23

The existence of a sensitive period for the ____ ____ means that after you pass that period, your ____ ____ won’t change as much or as fast.

Answer 23

visual cortex

Question 24

If an infant has a visual problem ____ we need to fix it ____. For example, cataracts on one or both eyes during infancy cause visual deprivation, and a delay in surgically repairing the cataracts limits future vision.

Answer 24

early

Question 25

Whereas most adults see objects and know almost immediately what they are, people who lived most of their lives with cloudy vision find it always difficult to guess what the objects are. The visual experience that most of us take for granted depends on years of ____.

Answer 25

practice