occipital and temporal lobe

Question 1

processing of visual information by the brain is…

Answer 1

hierarchal, with the complexity of the visual representation increasing from retina to visual association cortices and beyond

Question 2

what is there at the different stages of information processing

Answer 2

• functional differentiation with different neuron types or different brain regions processing different properties of visual stimuli

Question 3

what are simple features

Answer 3

• light intensity and wavelength
• 2D position in visual field

Question 4

how does visual information processing go from simple to complex features

Answer 4

combination and elaboration via parallel channels

Question 5

what are complex visual representations for perception and memory

Answer 5

• integrated information concerning form, surface, spatial relationships and movement
• integration with other sensory modalities

Question 6

what are the components of the occipital lobe

Answer 6

VI
V2
V3
V3A
V4
V5/MT

Question 7

what do neurons in the extrastriate cortex signal

Answer 7

• global properties of visual scenes and objects, rather than component properties
• V3 and V5
• neurons are differentiatley sensitive

Question 8

what does perceived colour of an object depend on

Answer 8

• wavelength reflected by object and wavelength reflected by surroundings

Question 9

what are neurons in V4 sensitive to

Answer 9

• colour sensitive - respond to wavelengths in the centre of their receptive field, depending on the wavelengths reflected from the background

Question 10

what are neurons in the primary visual pathway and V2 sensitive to

Answer 10

wavelength

Question 11

what happens in area V5

Answer 11

all information is put together for perception of pattern motion - global and holistic
- true overall direction

Question 12

what 2 streams are the visual information processing mediated by

Answer 12

• dorsal stream
• ventral stream

Question 13

what is the dorsal stream

Answer 13

• responsible for visuospatial and visuomotor processing
• allows movement
• directional info

Question 14

where is the dorsal stream

Answer 14

the posterior parietal cortex

Question 15

what is the ventral stream

Answer 15

• recognise objects and entities

Question 16

where is the ventral stream

Answer 16

• inferior temporal lobe

Question 17

what do inferior temporal lobe lesions impair

Answer 17

• object discrimination/recognition but not object location

Question 18

what do posterior parietal lesions impair

Answer 18

object location but not discrimination

Question 19

what did Milner and Goodale propose about the ventral and dorsal streams

Answer 19

• processes visual info for object perception whereas the dorsal stream processes visual info for visuospatially guided action

Question 20

how do patients with occipito-temporal brain damage support ventral streams

Answer 20

• they show severe forms of visual agnosia - deficits in visual perception

Question 21

how do patients with posterior parietal lobe lesions support dorsal streams

Answer 21

show optic ataxia - deficits in visually guided reaching with otherwise intact visual function

Question 22

what does the inferior temporal cortex receive and form

Answer 22

• receives inputs from extrastriate cortex and forms the final stage in the visual processing hierarchy of the ventral stream

Question 23

how do neurons in the inferior temporal cortex respond

Answer 23

very selectively to specific shapes and objects

Question 24

what do responses from neurons in the inferior temporal lobe show

Answer 24

• invariance to changes in size, orientation, and other properties - e.g. recognises object regardless of viewpoint
• sustained activity in absence of visual object, reflecting short term object memory

Question 25

what do some neurons in the inferior temporal lobe show highly selective responses to

Answer 25

individual faces - inferior temporal lobe keeps firing for the same face despite orientation changing, doesn't fire for different person's face

Question 26

what is at the end of the visual processing hierarchy

Answer 26

the medial temporal lobe

Question 27

what does the MTL do

Answer 27

- combines inputs from ventral and dorsal stream and receives additional inputs from other sensory modalities

Question 28

what is the MTL in position to do

Answer 28

- elaborate visual representations further and to generate multi-modal representations