Module 6.1

Question 1

What is the Law of Specific Nerve Energies?

Answer 1

Impulses in one neuron indicate light and impulses in another neuron indicate sound

Question 2

How is strength of a stimulus encoded?

Answer 2

It depends on the frequency of firing and relative rates of firing.

Question 3

Trace the path of light into the eye to the retina.

Answer 3

Cornea
Pupil
Iris
Lens

Question 4

What is the fovea?

Answer 4

an area specialized for acute, detailed vision

Question 5

How do cells in the fovea connect to other cells? How are these connections different in the periphery of the retina?

Answer 5

Each receptor in the fovea connects to a single bipolar cell and they connect to a single ganglion cell. In the periphery, more cells converge onto bipolar and ganglion cells.

Question 6

Compare foveal and peripheral vision with regard to location, sensitivity to dim light, and color vision.

Answer 6

Peripheral is the visual area to the side of you and has better sensitivity to dim light than foveal vision. Foveal is the visual area directly in front of you, it’s more sensitive to color and detail than the peripheral.

Question 7

What is a photopigment?

Answer 7

chemical that releases energy when struck by light

Question 8

What is the relationship of 11-cis-retinal to all-trans-retinal?

Answer 8

Light converts 11-cis-retinal to all-trans-retinal, thus releasing energy that activates second messengers within the cell

Question 9

What is an opsin?

Answer 9

proteins that modify the photopigments’ sensitivity to different wavelengths of light

Question 10

How did Young and Helmholtz account for color vision? Why is it hard to see small blue dots?

Answer 10

We perceive color through the relative rates of response by 3 kinds of cones, each kind maximally sensitive to a different set of wavelengths.
Long and medium-wavelength cones are a lot more abundant than short-length cones, which are for blue

Question 11

What kind of theory did Hering propose?

Answer 11

opponent-process theory-we perceive colors in terms of opposites

Question 12

What evidence supports Hering’s theory?

Answer 12

negative color afterimage

Question 13

What visual abillity does the Retinex Theory explain?

Answer 13

color constancy

Question 14

What is the genetic basis for most color blindness deficiency?

Answer 14

their long- and medium-wavelength cones have the same photopigment instead of different ones

Question 15

What is the blind spot?

Answer 15

the point where the optic nerve leaves the eye where there are no receptors