Vision

Question 1

Cones

Answer 1

Cones are responsive to bright light. They are responsible for color vision and our ability to see fine detail. There are 3 kinds (blue, green, and red)

Question 2

Rods

Answer 2

Rods are more numerous than cones and are more sensitive to dim light. They are mainly used for night vision. There is only one kind of rod

Question 3

Horizontal cells

Answer 3

Between photo receptors and bipolar cells

Question 4

Amacrine cell

Answer 4

Between bipolar cells and ganglion cells

Question 5

Geniculostriate system

Answer 5

Optic nerve —-> Lateral geniculate nucleus (found inside the thalamus) —-> Striate cortex (primary visual cortex) —-> Other visual cortical areas

Question 6

Tectopulvinar system

Answer 6

Optic nerve —-> Superior colliculus —-> Pulvinar —-> Other visual cortical areas

Question 7

Primary “x” cortex

Answer 7

Gets its information directly from the switchboard (thalamus)

Question 8

What is the boundary between the eyes and CNS?

Answer 8

The optic chiasm

Question 9

Parvocellular layers

Answer 9

Top 4 layers (3-6) receive from cones

Question 10

Magnocellular layers

Answer 10

Bottom 2 layers (1-2) receive from rods

Question 11

Ventral stream

Answer 11

“what” Identifying objects (what am i seeing)

Question 12

Dorsal stream

Answer 12

“how” Plan movement (How do i react to what im seeing)

Question 13

sensation

Answer 13

registration of physical stimuli from the environment by the sensory organs.

Question 14

perception

Answer 14

subjective interpretation of sensations by the brain.

Question 15

blindsight

Answer 15

subject can not identify objects in his blind area but could very accurately “guess” if a light had blinked on there and even where the light was located.

Question 16

How is receptor density related to sensitivity?

Answer 16

Sensitivity is directly proportional to receptor density. “Denser receptors enable smaller receptive fields – so sensory neurons can be more specific.”

Question 17

neural relay

Answer 17

Our sensory neurons connect to the cortex through a sequence of 3 or 4 intervening neurons. These stages comprise a neural relay, which can be modified at any level

Question 18

Generally, how do sensory neurons encode information?

Answer 18

Increasing or decreasing the frequency of action potentials

Question 19

lens & cornea

Answer 19

The cornea and lens of the eye, like the lens of a camera, focus light rays to project a backward, inverted image on a light-receptive surface.

Question 20

pupil

Answer 20

As light enters the eye, it is bent first by the cornea, travels through the pupil, and is then bent again by the lens. The curvature of the cornea is fixed, whereas small muscles adjust the curvature of the lens to focus nearby or far away.

Question 21

retina

Answer 21

Light-sensitive surface at the back of the eye consisting of neurons and photoreceptor cells.

Question 22

fovea

Answer 22

Region at the center of the retina that is specialized for high acuity; its receptive fields are at the center of the eye’s visual field.

Question 23

optic disk

Answer 23

“blind spot” Region of the retina where axons forming the optic nerve leave the eye and where blood vessels enter and leave; has no photoreceptors and is thus “blind”

• Located laterally from the fovea in each eye