Motion

Question 1

What is motion?

Answer 1

a change in an objects position over time

Question 2

What does static mean?

Answer 2

Not moving

Question 3

How do we detect motion

Answer 3

• We start with two adjacent neurons that registers a change in position
• needs to incorporate a delay which would account for change in time.

Question 4

A reichardt detector cannot tell the difference between:

Answer 4

continuous motion and an object disappearing in A then appearing in B

Question 5

What is apparent motion?

Answer 5

Perception of smooth motion resulting from rapid alternation of objects between locations

Question 6

What is aperture?

Answer 6

an opening that allows only a partial view of an object

Question 7

What is the aperture problem?

Answer 7

when a moving object is viewed through an aperture, thte direction of motion of the visible part of the object may be ambiguous.

Question 8

What is the brain structure is involved in motion?

Answer 8

the medial temporal lobe

Question 9

How do lesions effect motion perception?

Answer 9

lesions in the medial temporal lobe made it so monkeys needed 10x as many dots to correctly identify motion.

Question 10

What is interocular transfer?

Answer 10

transfer of an object from one eye to another.

Question 11

What does the optic flow have to do with collisions?

Answer 11

Optic flow lets you detect when an object is heading straight toward you.

Question 12

How do we compute TTC (time to contact)?

Answer 12

Tau- ratio of the retinal size of an object and the rate at which that size is increasing.

Question 13

What is identifying objects from motion?

Answer 13

We can identify objects on how they move- most useful for living things.

Question 14

What is biological motion?

Answer 14

Describes the way living things move.

Question 15

What role does the superior colliculus play in eye movement?

Answer 15

It’s a midbrain structure that initiates and guides eye movement.

Question 16

What are extraocular muscles?

Answer 16

Six muscles that are attached to each eye and are arranged in three pairs.

Question 17

What is smooth pursuit eye movement?

Answer 17

Smoothly following a moving target.

Question 18

What are saccades?

Answer 18

A rapid shift from one object to another

Used to scan an image or react to new object.

Question 19

What is saccadic suppression?

Answer 19

Visual sensitivity is reduced during saccades.

We are essentially blind while our eye is moving from one point to another- this is why you don’t see the work in a blur during a saccade.

Question 20

What is vergence?

Answer 20

Two eyes move in opposite direction

Convergence and divergence.

Question 21

What is the difference voluntary and reflexive eye movement?

Answer 21

Reflective are usually saccadic

Voluntary are mix of smooth pursuit and saccades.

Question 22

What is a comparator?

Answer 22

An area of the visual system that receives a copy of the signal from the motor system telling the eyes to move.

Question 23

How do we develop motion perception?

Answer 23

• develops over time
• infants have some reflexive eye movement at birth
• sensitivity of motion reaches maturity around 3-4yrs.

Question 24

What is akinetopsia?

Answer 24

A rare disorder that leads to loss of motion perception.

Caused by damage to MT