CHAPTER 3: The Eye and the Retina

Question 1

What did Hartline discover about ganglion cells and their receptive fields?

Answer 1

Harline used retinas from frogs to discover receptive fields by shining a light on them. He discovered that the spot activated a certain field of the retinal ganglion cells.

Question 2

What did Stephen Kuffler discover about ganglion receptive fields?

Answer 2

Kuffler found that receptive fields have on/off components -> on-center, off-surround, and off-center, on-surround (on means firing action potentials)

Question 3

How does lateral inhibition contribute to the center-surround organization of receptive fields?

Answer 3

• inhibition is coming from the sides
• in the center-surround, it is the circle around the middle

Question 4

What is the Hermann Grid, and how does it feature lateral inhibition?

Answer 4

Looking at an intersection: using fovea which has low receptive fields
When using peripheral vision, the receptive fields are large and don’t fit in the intersection, so whatever is around it is projected due to lateral inhibiton. Our brains interpret the world, hence the grey spot

Question 5

Explain the path of light as it travels through the eye to the brain

Answer 5

Light from the environment enters the eye through the pupil, and is focused by the cornea and lens to project a proximal stimulus onto the retina, that contains photoreceptors, and the signals from these photoreceptors travel through the optic nerve to the brain