Visual System Part 3

Question 1

V2 Prestriate cortex

Answer 1

receives visual information from V1
receptive fields are larger than V1
receptive fields are now binocular
receptive fields begin to show contextual effects
cells respond to imaginary lines
neurons show different firing if objects is in foreground or background

Question 2

Where does V2 send information

Answer 2

dorsal or ventral stream

Question 3

Dorsal stream

Answer 3

path that identifies location and direction of objects

also provides identification of certain types of movements

Question 4

Dorsal V3

Answer 4

receives information from V2 and V1
responds to large movements
very large receptive fields
first stage in processing changes in visual stimuli when you move

Question 5

MST/MT/V5

Answer 5

cortical center for perception of movement

neurons in this area integrate information from ground/figure movement, head movement, and line/object movement

Question 6

Area MT: Dorsal

Answer 6

global changes in visual motion

compensates for body’s movement in the environment

Question 7

Optic Flow

Answer 7

as we move around, entire scene shifts, magnifies around us

Question 8

Area MT: Ventral

Answer 8

identifies objects in motion
responds to motion
responds to images that depict motion 
Cells in MT can be selective to 
accelerate, direction, speed

Question 9

Simultagnosia

Answer 9

Difficult in perceiving multiple items

Question 10

Ventral simultagnosia

Answer 10

Can only be aware of one ‘thing’ at a time

Question 11

Dorsal simultagnosia

Answer 11

Can be aware of multiple objects but can only identify one at a time

Question 12

Hemispatial neglect

Answer 12

patients appear to neglect half their visual field

Question 13

Akinetopsia

Answer 13

an inability to perceive motion

vision is replaced by frozen images

Question 14

Ventral stream

Answer 14

identifies contents of visual field

important for object, identification, colour, and form

Question 15

Ventral V3

Answer 15

receives information from V1/V2

passes information on to V4

Question 16

Ventral V4

Answer 16

encodes more complicated visual information
colour, and simple shapes make neuron fire
helps keep colour information consistent in the brain
neurons fire faster when stimulus is being attended to

Question 17

Globs

Answer 17

areas of V4 that are sensitive to colour

Question 18

Colour Constancy

Answer 18

mechanism that allows us to see colour in a similar way even in different lighting situations and distances

Question 19

How do we see 3D

Answer 19

the mind creates an illusion using shading, lines, patterns, and contours
integrates information from both dorsal and ventral stream
Final output is in the inferotemporal Cortex which is activated by 3D shapes

Question 20

What is the 3-D model of recognition

Answer 20

inside our brain is a 3D model of the object which we match to what we are perceiving

Question 21

Recognition of components

Answer 21

objects are brown down into simple geometric shapes which can be combined to form shapes

Question 22

Viewpoint dependent

Answer 22

specific orientation of object is stored, and there are many memories of the same object

Question 23

Multiple Views

Answer 23

mix of all the other theories

suggests components/3D model for general objects, but viewpoint dependence for specific things

Question 24

Lateral Orbital Cortex

Answer 24

recognizes objects

neurons fire when they recognize a texture but fire the most when they recognize an object

Question 25

Parahippocampal place area

Answer 25

activated when viewing landscapes, cityscapes, houses, or rooms

Question 26

Fusiform face area

Answer 26

activated when shown faces, cartoon faces, drawing of faces

Question 27

Theory for FFA function

Answer 27

because of face’s importance, we evolved an area specialized for faces
because of face’s importance, we evolved an area specialized for differentiating between very similar things

Question 28

Prosopagnosia

Answer 28

after damage to the face, they are unable to recognize faces

Question 29

Blindsight

Answer 29

patients are perceptually bind, report no vision
blindness is typically from V1 damage
when forced to choose, will show better than chance performance on a variety of tasks
will sometimes ‘dodge’ objects while moving

Question 30

How can patients with blindsight dodge objects?

Answer 30

LGN sends some projections directly to extrastriate areas of visual cortex
these limited projections aren’t enough to allow subjects to perceive vision, but can subtly influence rest of cortex