Lecture 28 - Higher Visual Functions: Motion recognition (AMcK)

Question 1

Motion is a perceptual inference - sometimes there is real object motion (ball moving) and sometimes not (inferring motion from static things (film is a series of static images giving off the appearance of motion)

Answer 1

Motion is a perceptual inference - sometimes there is real object motion (ball moving) and sometimes not (inferring motion from static things (film is a series of static images giving off the appearance of motion)

Question 2

Apparent motion

Answer 2

Sequence of lights in a neon sign

Question 3

Optic flow

Answer 3

Movement of the world: “observer motion” - continuous motion cues all around us

Question 4

Motion after-effect

Answer 4

After viewing a moving visual stimulus for a time and then fixating a stationary stimulus. The stationary stimulus appears to move in the opposite direction to the original (physically moving) stimulus. e.g. Looking at waterfall going downwards for a while then looking at rocks next to it, the rocks look like they are going upwards

Question 5

Why is movement important to the segmentation of objects?

Answer 5

Movement of an object allows us to differentiate it from its background (which may be similar in colour and orientation)

Question 6

T/F - V1 cells do not show direction selectivity at all

Answer 6

F

Question 7

T/F - The proportion of cells that are direction selective vary according to V1 layer

Answer 7

T

Question 8

MT neurons respond most strongly when there is coherent motion in the moving components of a visual stimulus.

Answer 8

MT neurons respond most strongly when there is coherent motion in the moving components of a visual stimulus

Question 9

Single cells in Area MT respond to a global direction of motion When shown objects moving in two directions, cells in V1 will only encode one of the component directions, not the integrated directions

Answer 9

Single cells in Area MT respond to a global direction of motion When shown objects moving in two directions, cells in V1 will only encode one of the component directions, not the integrated directions

Question 10

Which receptive fields are larger and more involved in optic flow and complex motion (e.g. expansion, constriction) - MT or MST?

Answer 10

MST

Question 11

What is biological motion?

Answer 11

Act of perceiving the fluid unique motion of a biological agent.

Question 12

Akinetopsia

Answer 12

Visual motion blindness

Question 13

Besides the typical LGN -> V1 -> MT motion pathway, what other motion pathways are there?

Answer 13

Colliculo-cortical pathway Retina -> SC -> V5/MT