Week 2

Question 1

What is the “inverse problem” in vision?

Answer 1

It’s the challenge of not being able to know the exact contributions of light, reflectance, and transmittance to what we see.

Question 2

Why is vision an “inverse problem”?

Answer 2

Because we can’t trace back the exact source of the visual information reaching our eyes.

Question 3

Why do we not see the world upside down?

Answer 3

Even though light hits our eyes upside down, the brain reconstructs the image so we see the world correctly.

Question 4

What does it mean that vision involves “inference and reconstruction”?

Answer 4

Our brain takes incoming visual information and puts it together to create a coherent view of the world.

Question 5

How does the presumed light source affect perception?

Answer 5

Our brain expects light to come from above (like the sun), influencing how we perceive shadows and objects.

Question 6

What is visual perception?

Answer 6

It is our awareness of seeing and the process by which the brain interprets visual information to help us understand the world.

Question 7

What are the steps involved in visual processing?

Answer 7

1. Light enters the eye
2. The eye captures the light
3. Brain pathways process the signal
4. Mental processing occurs
5. We experience visual perception.

Question 8

What is light in terms of vision?

Answer 8

Light is an electromagnetic wave that enters the eye and allows us to see.

Question 9

What part of the light spectrum can humans see?

Answer 9

Humans can see only the visible light range, between 400-700nm.

Question 10

What is the fovea?

Answer 10

The fovea is the center of the retina responsible for sharp vision (visual acuity) and has the highest concentration of cone cells.

Question 11

Where is detailed visual analysis confined?

Answer 11

It is confined to the part that falls within central vision, the fovea.

Question 12

What happens to information in peripheral vision?

Answer 12

The brain creates a “uniformity illusion,” filling in gaps in peripheral vision to make it appear uniform.

Question 13

How does light enter the brain from the eyes?

Answer 13

Light enters the eye as photons and is converted into electrical signals by the retina before traveling to the brain via the optic nerve.

Question 14

What is transduction in the retina?

Answer 14

Transduction is the process where photoreceptors in the retina convert light energy into neural signals.

Question 15

What happens to the neural signal after transduction in the retina?

Answer 15

The neural signal leaves the eye through the optic nerve and travels to the brain

Question 16

Why do we have a ‘blind spot’ in our vision?

Answer 16

There is a hole in the retina where the optic nerve exits, so no photoreceptors are present, but the brain fills in the gap automatically.

Question 17

Do we perceive a ‘blind spot’ in our vision?

Answer 17

No, because the brain fills in the missing information based on surrounding visual input.

Question 18

What is the “Dorsal” or “How” pathway?

Answer 18

It’s a visual pathway to the parietal lobe that supports action-oriented behaviors, like reaching for objects, also known as “vision-for-action.”

Question 19

What happens if the primary visual cortex (V1) is damaged?

Answer 19

Damage to V1 can result in cortical blindness, where the eyes work but the brain cannot process visual information.

Question 20

What is blindsight?

Answer 20

It’s when people with cortical blindness can still respond to visual stimuli (like reaching for objects) without being consciously aware of seeing.

Question 21

What is the role of the superior colliculus in blindsight?

Answer 21

It still receives visual information, enabling people with cortical blindness to unconsciously respond to visual stimuli.

Question 22

What are fixations in vision?