Vision 3: From sensation to perception

Question 1

How did they determine what visual areas are not part of conscious visual processing by elimination using colour?

Answer 1

When flicking red and green at 30Hz we do not consciously process this and so see it as yellow. When recording brain activity, when the visual areas V1 and hV4 respond to the 30Hz stimulus they can determine they are not NCC

Question 2

How can this been done in a similar fashion without colour?

Answer 2

Using a mask after the stimulus and then the original orientation can still be decoded from the area V1 above chance level despite not being consciously able to report it

Question 3

Do the visual areas of a monkey become activated when under anaethstesia? What does this mean you’d nearly be eliminating the whole brain

Answer 3

Yes, meaning that if you were to go by this method of elimination

Question 4

What are bistable stimuli?

Answer 4

When a stimulus remains constant yet conscious percept switches spontaneously (illusions)

Question 5

What is meant by binocular rivalry?

Answer 5

Presenting two different stimuli to the two eyes (stationary for minutes) results in spontaneous switches of perceiving the one (say left eye) stimulus, then the other (right eye), then the first again, etc. Dominance lasts several seconds, but may vary in length from switch to switch. Dominance length has a characteristic frequency distribution

Question 6

What visual elements can influence binocular rivalry?

Answer 6

A higher contrast (f) or sharper (g) image dominates longer over a less contrast or less sharp image

Question 7

How was this used in determining if cells were involved in NCC?

Answer 7

Face selective cells in IT only respond when the face is dominating (seen) in binocular rivalry. This was replicated in other higher level visual areas but not in lower levels such as V1, V2, V4 or MT

Question 8

What do MT neurons contribute to?

Answer 8

Perceived motion

Question 9

What does the strength of a perceived illusion indicate (ebbinghaus or ponzo)

Answer 9

negatively correlates with size of area V1

Question 10

Summing this up, which visual regions contribute to the conscious percept

Answer 10

idk dawg Depending on stimuli used, many regions of the brain seem involved in how things are perceived, and thus contribute to the conscious visual percept