Lecture 12: Motion

Question 1

Damage to the _________________ in humans leads to perception of movement of stationary environment with movement of eyes.

Answer 1

Medial superior temporal area

Question 2

When do real movement neurons respond/not respond?

Answer 2

• respond when a stimulus moves
• do not respond when eyes move

Question 3

What are reichardt detectors? Describe in detail.

Answer 3

• model of a simple neural circuit that could fire in response to movement in one direction
• neuron A and B send signals to OUTPUT UNIT, which compares to see if the signals are synchronized
• neuron A signal goes through DELAY UNIT before output unit
• motion is perceived if signals from neuron A and B are received by the output unit at the same time (i.e. signals from A and B are multiplied, and the neuron fires if >0…does not fire if = 0)

Question 4

Where does perception of motion begin?

Answer 4

Striate cortex (V1)

Question 5

What do complex cortical cells respond to?

Answer 5

Movement of the ends of objects

Question 6

Which area of the brain is implicated in other aspects of motion perception?

Answer 6

Middle temporal area

Question 7

Normal monkeys can detect motion with coherence of 1-2%. Monkeys with lesions in _______________ cannot detect motion until the coherence is 10-20%.

Answer 7

Middle temporal cortex

Question 8

_________________ applied to _____________ in humans disrupts ability to perceive direction in a random pattern of moving dots.

Answer 8

Transcranial magnetic stimulation (TMS); MT area

Question 9

Review slide 13

Answer 9

Slide 13

Question 10

What is the shortest path constraint?

Answer 10

Apparent movement tends to occur along the shortest path between 2 stimuli

Question 11

FMRI shows that motor cortex is activated for perception of ____________ movement only.

Answer 11

Possible (vs. Impossible)

Question 12

What is biological motion?

Answer 12

Self-produced motion of a person or other living organism

Question 13

What is the point-light walker stimulus?

Answer 13

Created by placing lights on the joints of a living organism, which convey their pattern of movement (and biological movement)

Question 14

Which area is most active for biological motion?

Answer 14

• Superior temporal sulcus (STS)
• others show activation of mirror neurons in FFA AND PFC

Question 15

TMS applied to the _______________ impairs detection of biological motion.

Answer 15

Superior temporal sulcus

Question 16

What are the functions related to motion in the striate cortex?

Answer 16

Direction of motion across small receptive field

Question 17

What are the functions related to motion in the middle temporal area?

Answer 17

Direction and speed of object motion

Question 18

What are the functions related to motion in the medial superior temporal area?

Answer 18

Processing optic flow; locating moving objects; reaching for moving objects

Question 19

What are the functions related to motion in the superior temporal sulcus?

Answer 19

Perception of biological motion (animal/human)

Question 20

What is implied motion?

Answer 20

Conveyed by still pictures that depict an action which involves motion

Question 21

What is representational momentum?

Answer 21

Implied motion depicted in a photo an be “carried out” or continue in the observer’s mind

Question 22

When looking at still pictures, do people take longer to time-forward or time-backward pictures?

Answer 22

time-forward because the anticipation interferes with responding

Question 23

What finding can provide evidence for the fact that perception of biological motion may not depend on visual experience?

Answer 23

newly hatched chicks have a preference for biological motion