Chapter 13 - Occipital Lobe

Question 1

What are the subdivisions of the occipital lobe

Answer 1

V1, V2, V3, V4, V5, V3A

Question 2

what are the principal connections of the occipital lobe

Answer 2

visual pathway is complex, but have a few simple principles:

1. V1 (striate cortex) is first processing level, receives largest input from lateral geniculate nucleus and projects to other occipital regions
2. V2 second processing level, specializes information more, projects to all other regions
3. after V2, 3 parallel pathways to parietal cortex and inferior temporal cortex (dorsal, ventral, STS stream)

Question 3

what does the occipital lobe do

Answer 3

primarily responsible for visual processing and is the brain’s visual center

Question 4

Distinguish between geniculostriate and tectopulvinar visual pathways

Answer 4

Geniculostraite pathway:
receives info from eye, to lateral geniculate nucleus, to V1
responsible for conscious visual perception
if damaged, can still have tectopulvinar pathway but it is not conscious
Tectopulvinar pathway:
info from eye, to superior colliculus, to pulvinar
involved in unconscious visual processing (motion and orientation)

Question 5

V1

Answer 5

largest area in human cortex
heterogenous
blobs for colour
interblobs for form and motion

Question 6

V2

Answer 6

heterogenous
thick stripes for colour
thin stripes for form
pale stripes for motion

Question 7

what is the distinction between Ungerleider and Mishkin model of dorsal and ventral streams

Answer 7

dorsal = where
V1 to parietal lobe primarily involved in in processing spatial location
ventral = what
V1 to temporal lobe and involved in object recognition

Question 8

what is the distinction between Milner and Goodale model of dorsal and ventral streams

Answer 8

dorsal = HOW
visually guided actions, real-time actions
ventral = what
similar to other model, object recognition

Question 9

What is visual agnosia

Answer 9

neurological condition
inability to recognize or interpret visual stimuli
can see objects but not identify or make sense of them

Question 10

What is apperceptive agnosia

Answer 10

failure of object recognition
struggle to copy drawings or recognize objects
associated damage to POSTERIOR lesion

Question 11

What is associative agnosia

Answer 11

associated to damage of ANTERIOR TL lesion
see an object and describe, but fail to name it

Question 12

Why do people with large lesions in V1 appear to be blind, even when input can get to other visual areas

Answer 12

because V1 is crucial for conscious vision, some of the info can reach higher visual areas through the tectopulvinar pathway, where people can unconsciously detect motion or spatial cues called blindsight

Question 13

V3

Answer 13

dynamic form, shape and form

Question 14

V4

Answer 14

colour (but not just colour, also position, depth, structure)

Question 15

V5

Answer 15

motion in the dorsal stream

Question 16

V3A

Answer 16

form of shape and contour in dorsal stream

Question 17

What is vision for action

Answer 17

visual processing required to guide specific movements towards an object

Question 18

what is action for vision

Answer 18

top down process movement directing where we look/gaze

Question 19

what is visual recognition

Answer 19

ability to identify and categorize objects based on visual information
involves temporal neurons

Question 20

what is visual space

Answer 20

egocentric - things relative to us, involves parietal lobe
allocentric - our location in the world
temporal and parietal neurons involved

Question 21

What is visual attention

Answer 21

selective focus on certain things and not others
temporal neurons involved

Question 22

What is a top-down sensory process

Answer 22

knowledge is top down compared to perception being bottom-up
our brain utilizes prior knowledge to guide perception of incoming sensory information and make predictions for the future

Question 23

where do top-down sensory processes arise

Answer 23

extensive networks from the prefrontal cortex and occipital and temporal lobes

Question 24

What is the distinction between cases DF and VK

Answer 24

DF had damaged ventral stream, working dorsal stream therefore could draw from memory but couldnt draw from a model beside
VK had damaged dorsal stream, couldn’t pick up the object but could name it

Question 25

what is aphantasia

Answer 25

absence of visual imagery, unable to generate mental image

Question 26

What is blindsight

Answer 26

damage to V1, cortically blind, cannot consciously perceive visual stimuli
distinction between visual perception and action
rely on tectopulivnar pathway that bypasses V1

Question 27

What is visual imagery

Answer 27

ability to create a mental representation of objects that are not currently being seen
ex. visualize your mom’s face

Question 28

How can we account for visual imagery in neuropsychology

Question 29

What results if there is damage to the RIGHT optic nerve

Answer 29

complete loss of vision in right eye

Question 30

What is the result if there is damage to the LEFT optic nerve

Answer 30

complete loss of vision in the left eye

Question 31

What is the result if there is damage to the optic chiasm

Answer 31

bitemporal hemianopia
loses ability to see outer sides of both left and right

Question 32

What is the result if there is damage to the right side behind the optic chiasm

Answer 32

homonymous hemianopia
person loses vision in same side of both eyes

Question 33

what is the result if there is damage to the optic radiations

Answer 33

quadrantanopia
person loses site in a quadrant of their vision

Question 34

What is the result if there is damage to the visual cortex

Answer 34

quandrantanopia with macular sparing
person loses site in a quadrant of their vision but the centre is spared

Question 35

What is a scotoma

Answer 35

partial loss of vision or blind spot