Depth Perception

Question 1

What us not neccesary for depth perception

Answer 1

Binocular cues (I.e. closing one eye and you can still see depth)

Question 2

Optic flow def

Answer 2

Optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and object

Question 3

What provides us with depth infomation?

Answer 3

Motion parallax

Question 4

What is motion parallax?

Answer 4

Motion parallax refers to the fact that objects moving at a constant speed across the frame will appear to move a greater amount if they are closer to an observer (or camera) than they would if they were at a greater distance

Question 5

What is special about primates for depth perception with example

Answer 5

We have smooth eye movements - i.e we can focus on something and maintain focus on that object as we move around. e.g. holding thumb and turning head side to side will mean only background moves side to side.

Question 6

Where does motion parallax occur?

Answer 6

Middle temporal area

Question 7

What did the gerbil study in 1984 do to show visual info from headmovements are important for depth perception

Answer 7

Visual motion resulting from head movements is a source of depth information- Gerbils model.
They trained gerbils to jump across a moving platform to another (the researchers varied the distance from each platform) whilst gaze is fixed on a singular point and demonstrated motion.

Forces gerbil to gauge distance of platform whilst gaze is focused on singular point. Able to track size of gaps accurately and make it to the other side- they can do this without binocular vision, so even with monocular deprivation they were able to jump across and land.
The behavior the gerbils demonstrated was an exploratory ‘head bob’ motion to judge distance from each platform. Interestingly, the number of head bobs correlated to the size of the gap (more head bobs = larger gap)

Mice can be trained to jump too and also make head bob movements- Distance estimation from monocular cues used machine learning to leverage findings.

Question 8

Head bobs in clusters in Mono vs Binoc mice

Answer 8

Head bobs more frequent in monocular cued mice.
There was a positive correlation between headbob frequency and volume of the (SC)

Question 9

When do the head bobs occur?

Answer 9

Just before the mice/gerbils jump

Question 10

Which brain region is responsible for

Answer 10

V1 visual cortex

Question 11

What cue does motion parallax rely on?

Answer 11

Motion parallax is a monocular visual cue