Lecture 13: Vision 2

Question 1

Describe how lateral inhibition works

Answer 1

horizontal cell synapses from the surround to the photoreceptor of the center. It releases GABA when surround photoreceptor is depolarized, prevents the center photoreceptor from depolarizing

Question 2

Describe how an On-center/off surround works

Answer 2

activated when light shines in the center, inhibited when light shines on the surround

Question 3

Describe how an off-center/on-surround works

Answer 3

activated when light shines on the surround, inhibited when light shines on the center

Question 4

Why is center-surround organization useful?

Answer 4

Used to see boundaries and edges. Because there is less excitation/lateral inhibition, or more, depending on the type of cell, then you can see the edges better

Question 5

Describe an on and off bipolar cell

Answer 5

ON: has mGluR receptors. When there is no glu released, mGluR isn’t active, so the TRPM1 Na+ channels are no longer inhibited and bipolar cell depolarizes

OFF: has iGLuR receptors. when glu is released, opens up ion channels so cell depolarizes and activates ganglion cell