Chapter 3: Spatial vision from spots to stripes--Vocab

Question 1

acuity

Answer 1

The smallest spatial detail that can be resolved.

Question 2

adaptation

Answer 2

A reduction in response caused by prior or continuing stimulation.

Question 3

aliasing

Answer 3

Misperception of a grating due to undersampling.

Question 4

amblyopia

Answer 4

A developmental disorder characterized by reduced spatial vision in an otherwise healthy eye, even with proper correction for refractive error. Also known as lazy eye.

Question 5

anisometropia

Answer 5

A condition in which the two eyes have different refractive errors (e.g., one eye is farsighted and the other not).

Question 6

column

Answer 6

A vertical arrangement of neurons.

Question 7

complex cell

Answer 7

A neuron whose receptive-field characteristics cannot be easily predicted by mapping with spots of light.

Question 8

contralateral

Answer 8

Referring to the opposite side of the body (or brain).

Question 9

contrast sensitivity function (CSF)

Answer 9

A function describing how the sensitivity to contrast (defined as the reciprocal of the contrast threshold) depends on the spatial frequency (size) of the stimulus.

Question 10

contrast threshold

Answer 10

The smallest amount of contrast required to detect a pattern.

Question 11

contrast

Answer 11

The difference in luminance between an object and the background, or between lighter and darker parts of the same object.

Question 12

cortical magnification

Answer 12

The amount of cortical area (usually specified in milli­meters) devoted to a specific region (e.g., 1 degree) in the visual field.

Question 13

cycle

Answer 13

For a grating, a pair consisting of one dark bar and one bright bar.

Question 14

cycles per degree

Answer 14

The number of pairs of dark and bright bars per degree of visual angle.

Question 15

cytochrome oxidase (CO)

Answer 15

An enzyme used to reveal the regular array of “blobs,” which are spaced about 0.5 millimeter apart in the primary visual cortex.

Question 16

end stopping

Answer 16

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.

Question 17

filter

Answer 17

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.

Question 18

hypercolumn

Answer 18

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.

Question 19

ipsilateral

Answer 19

Referring to the same side of the body (or brain).

Question 20

koniocellular cell

Answer 20

A neuron located between the magnocellular and parvocellular layers of the lateral geniculate nucleus.

Question 21

lateral geniculate nucleus (LGN)

Answer 21

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.

Question 22

magnocellular layer

Answer 22

Either of the bottom two neuron-containing layers of the lateral geniculate nucleus, the cells of which are physically larger than those in the top four layers.

Question 23

ocular dominance

Answer 23

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.

Question 24

orientation tuning

Answer 24

The tendency of neurons in striate cortex to respond optimally to certain orientations and less to others.

Question 25

parvocellular layer

Answer 25

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.

Question 26

phase

Answer 26

The relative position of a grating.

Question 27

primary visual cortex (V1), area 17, or striate cortex

Answer 27

The area of the cerebral cortex of the brain that receives direct inputs from the lateral geniculate nucleus, as well as feedback from other brain areas, and is responsible for processing visual information.

Question 28

simple cell

Answer 28

A cortical neuron with clearly defined excitatory and inhibitory regions.

Question 29

sine wave grating

Answer 29

A grating with a sinusoidal luminance profile.

Question 30

spatial frequency

Answer 30

The number of grating cycles in a given unit of space.

Question 31

spatial-frequency channel

Answer 31

A pattern analyzer, implemented by an ensemble of cortical neurons, in which each set of neurons is tuned to a limited range of spatial frequencies.

Question 32

strabismus

Answer 32

A misalignment of the two eyes such that a single object in space is imaged on the fovea of one eye, and on a nonfoveal area of the other (turned) eye.

Question 33

tilt aftereffect

Answer 33

The perceptual illusion of tilt, produced by adaptation to a pattern of a given orientation.

Question 34

topographical mapping

Answer 34

The orderly mapping of the world in the lateral geniculate nucleus and the visual cortex.

Question 35

visual angle

Answer 35

The angle subtended by an object at the retina.

Question 36

visual crowding

Answer 36

The deleterious effect of clutter on peripheral object recognition.