L27 - DepthPerception_2016(AMcK)

Question 1

Can you see depth perception without binocular vision?

Answer 1

Yes - when you shut one eye, the world doesn’t go flat - it still has depth

Question 2

Horopter - what is it? How does it give us perception of depth?

Answer 2

A line or surface containing all those points in space of which images fall on corresponding points of the retinas of the two eyes.

Anything slightly in front or behind the horopter doesn’t land on corresponding points - this tells us when something is behind or in front

Question 3

When is the first point in the visual pathway where neurons receive binocular input?

Answer 3

V1

Question 4

Borders provide a cue about occlusion which can tell us something is in front or behind without using the depth cue. What do random dot stereograms demonstrate?

Answer 4

That depth can be seen without borders/edge cues

Question 5

Do V1 cells encode disparity from random-dot-stereograms?

Answer 5

Yes

Question 6

Some linked cells in MST not only tuned to direction but also tuned to?

Answer 6

Disparity - providing info about parallax, depth cues for self-motion

Question 7

Objects with more/less detail, size, sharp texture are seen as closer

Answer 7

More detailed, larger, sharper textures

Question 8

When does binocular rivalry occur?

Answer 8

When dissimilar images are presented to corresponding retinal locations in the two eyes, the two stimuli compete for perceptual dominance (you don’t see a fused image, you see a few moments of image from the right, then the left)

Question 9

Neuronal mechanisms underpinning binocular rivalry

Answer 9

• Incompletely understood
• Evidence for early stage encoding of monocular info (LGN/V1)
• Evidence for residual encoding of the suppressed visual signal from brain imaging studies: not sufficient to generate a visual percept

Question 10

Parallax

Answer 10

Objects move at different speeds on the retina depending on the distance from the observer (assuming a static environment) - the objects in the distance appear to move more slowly than the objects close to the camera.

Question 11

Kinetic depth effect

Answer 11

Person is stationary but the object is moving (e.g. rotating). The retinal velocities depend on the distance of each feature from the observer.
*Motion cues providing info about depth as they are moving at different speeds