Chapter 3: Key Terms

Question 1

acuity

Answer 1

The smallest spatial detail that can be resolved at 100% contrast.

Question 2

adaptation

Answer 2

A reduction in response caused by prior or continuing stimulation.

Question 3

amblyopia

Answer 3

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 4

anisometropia

Answer 4

A condition in which two eyes have different refractive errors. (ie. one is far sighted and the other is not).

Question 5

CO blobs

Answer 5

Regular arrays of blobs spaced 0.5 millimetres apart in the triage cortex (V1), so named because their presence is visualized by staining with the enzyme cytochrome oxidase (CO). They may function in colour perception.

Question 6

contrast sensitivity functions (CSF)

Answer 6

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

Question 6

columns

Answer 6

A vertical arrangement of nuerons. Nuerons within a single field tend to have similar receptive fields and similar orientation preferences.

Question 7

complex cells

Answer 7

A cortical nueron whose receptive field does not have clearly defined excitatory and inhibitory regions.

Question 8

contralateral

Answer 8

Referring to the opposite side of the body or brain.

Question 9

contrast

Answer 9

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

Question 10

contrast threshold

Answer 10

The smallest amount of contrast to detect a pattern.

Question 11

cortical magnification

Answer 11

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

Question 12

critical period

Answer 12

1. A phase in the life span during which abnormal early experience can alter normal neuronal development.
2. A period in time during development when the organism is particularly susceptible to developmental change. There are critical periods in the development of binocular vision, human language, and so on.

Question 13

cycle

Answer 13

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

Question 14

cycles per degree

Answer 14

The number of grating cycles per degree of visual angle.

Question 15

eccentricity

Answer 15

1. The distance between the retinal image and the fovea.
2. The angular distance from the fovea (the region of highest visual acuity).

Question 16

end stopping

Answer 16

The process by which the cell in the cortex increases it’s ring rate as the length of the bar increases as the bar fills up its receptive field, and then it decreases it’s firing rate as the bar is lengthened further.

Question 17

filter

Answer 17

An acoustic, electrical, electronic, or optical device, instrument, computer program, or nueron that allows the passage of some range of parameters (e.g., orientations, frequencies) and blocks the passages of others..

Question 18

Fourier analyses

Answer 18

A mathematical procedure by which any signal can be separated by component sine waves at different frequencies.

Combining the sine waves (Fourier synthesis) will reproduce the original signal.

Question 19

hypercolumn

Answer 19

A 1-millimeter block of striate cortex contains 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 20

ipsilateral

Answer 20

Referring to the same side of the body or brain.

Question 21

koniocellular cells

Question 22

lateral geniculate nuclei (LGNs)

Question 23

magnocellular layers

Question 24

ocular dominance

Question 25

orewrintation tuning

Question 26

parvocellular layers

Question 27

phase

Question 28

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

Question 29

simple cells

Question 30

sine wave grating

Question 31

Spatial frequency

Question 32

spatial-frequency channels

Question 33

strabismus

Question 34

tilt aftereffect

Question 35

topographical mapping

Question 36

visual angle

Question 37

visual crowding