H7 The seeing brain

Question 1

sensation

Answer 1

the effects of a stimulus on the sensory organs

Question 2

perception

Answer 2

the elaboration & interpretation of a sensory stimulus based on previous knowledge

Question 3

retina

Answer 3

internal surface of the eyes that consists of multiple layers. some layers contain photoreceptors that convert light to neural signals & others consist of neurons themselves

Question 4

rod cells

Answer 4

type of photoreceptor specialized for low levels of light intensity

Question 5

cone cells

Answer 5

type of photoreceptor specialized for high levels of light intensity & detection of different wavelenghts

Question 6

receptive field

Answer 6

region of space that elicits a response from a given neuron

Question 7

fovea

Answer 7

point with the highest concentration of cones

Question 8

blind spot

Answer 8

the point at which the optic nerve leaves the eye (no rods & cones present here)

Question 9

primary visual cortex (V1)

Answer 9

1st stage of visual processing in the cortex; combines simple visual features into more complex ones

Question 10

simple cells

Answer 10

in vision, cells that respond to light in a particular orientation /points of light along that line

Question 11

complex cells

Answer 11

in vision, respond to light in a particular orientation but not to single points of light

Question 12

hypercomplex cells

Answer 12

in vision, respond to particular orientations & lenghts

Question 13

hemianopia

Answer 13

cortical blindness restricted to 1 half of the visual field (damage in V1 in 1 hemisphere)

Question 14

quandrantanopia

Answer 14

cortical blindness restricted to a quarter of the visual field

Question 15

scotoma

Answer 15

small region of cortical blindness

Question 16

retinopic organization

Answer 16

the receptive fields of a set of neurons are organized in such a way as to reflect the spatial organization present in the retina

Question 17

blindsight

Answer 17

symptom in which patient denies having seen a visual stimulus even though behavior implies that stimulus was in fact seen

Question 18

ventral stream

Answer 18

pathway in vision extending from occipital lobes →temporal lobes involved in object recognition, memory & semantics

Question 19

dorsal stream

Answer 19

pathway in vision from occipital lobes → parietal lobes involved in visually guided action & attention

Question 20

achromatopsia

Answer 20

brain damage that impairs color perception

Question 21

akinetopsia

Answer 21

brain damage that impairs movement perception

Question 22

V4

Answer 22

region of the extrastriate cortex associated with color perception

Question 23

V5

Answer 23

region of the extrastriate cortex associated with motion perception

Question 24

color constancy

Answer 24

color of a surface is perceived as constant even when illuminated in different lighting conditions

Question 25

biological motion

Answer 25

the ability to detect whether a stimulus is animate or not from movement cues alone

Question 26

structural descriptions

Answer 26

a memory representation of the 3D structure of objects

Question 27

apperceptive agnosia

Answer 27

failure to understand the meaning of objects due to a deficit at the level of object perception

Question 28

associative agnosia

Answer 28

failure to understand meaning of objects due to deficit at level of semantic memory

Question 29

figure-ground segregation

Answer 29

process of segmenting a visual display into objects versus background surfaces

Question 30

Gestalt approach

Answer 30

5 basic principles of how visual features are combined
1) law of proximity
2) law of similarity
3) = of good continuation
4) = of closure
5) = of common fate

Question 31

lateral occipital complex (LOC)

Answer 31

region of the brain that is specialized for processing object shapes

Question 32

integrative agnosia

Answer 32

failure to integrate parts into wholes in visual perception

Question 33

object constancy

Answer 33

understanding that objects remain = irrespective of differences in viewing condition

Question 34

viewpoint-invariant theories

Answer 34

theories that argue that particular object parts or features are mapped directly to structural descriptions

Question 35

viewpoint-dependent theories

Answer 35

argue that seeing an object from an unusual view requires a ‘mental rotation’ into a normal viewpoint

Question 36

adaptation

Answer 36

reduced neural response to a stimulus/stimulus feature that is repeated

Question 37

category specificity

Answer 37

notion that the brain represents different categories in different ways

Question 38

face recognition units (FRUs)

Answer 38

stored knowledge of the 3D structure of familiar faces

Question 39

person identity nodes (PINs)

Answer 39

abstract description of people that links together perceptual knowledge with semantic knowledge

Question 40

prosopagnosia

Answer 40

inability to recognize previously familiar faces

Question 41

fusiform face area (FFA)

Answer 41

area in the inferior temporal lobes that responds more to faces & is implicated in processing facial identity

Question 42

categorical perception

Answer 42

tendency to perceive ambiguous or hybrid stimuli as either one thing or the other

Question 43

geniculostriate pathway

Answer 43

pathway from eye to brain that goes via lateral geniculate nucleus (LGN) and terminates in striate
cortex (another name for V1)