Topic 2: Neural Foundations

Question 1

travel of stimulus

Answer 1

distal stim
proximal stim
eye
retina
fovea

Question 2

optic disc

Answer 2

axons need to escape to the brain

travel through the optic nerve

Question 3

proximal stim for the eye

Answer 3

visible light
400 - 700 nm
higher wavelength = lower frequency

Question 4

accomodation

Answer 4

change in the shape of the lens
lens will adjust based on an object (far vs close)
due to ciliary muscles

Question 5

hyperopia

Answer 5

farsightedness

-image focused behind the plane of the retina

Question 6

myopia

Answer 6

image focused in front of the plane of retina
nearsightedness
think “near in time”

Question 7

rods

cones

Answer 7

-shade, more sensitive and works in low light (120 mil)
-focus on colour, work in high light (6 mil)
-high density of cones near the fovea (medial)
decrease in concentraion of rods and cones in periphery, low detail in peripheral vision

Question 8

gaze contingent rendering

Answer 8

put eye trackers in vr so that periphery doesnt need to be all HD but only fovea tracked locations

Question 9

rod and cone biology

Answer 9

photodetectors instead of dendrites
discs similar to cell membranes - molecules that absorb light are embedded within the membrane
more layers = higher chance for light to be detected (opsin)

Question 10

opsin

Answer 10

more layers means there is higher chance for light to be absorbed
-retinal specialized piece attached to opsin, when light is absorbed it will be isomerized and change shape

Question 11

path of light

Answer 11

ganglion cells
bipolar cells
rods/cones

Question 12

molecular cascade

Answer 12

single photon absorbed by retinal leads to an amplified effect involving millions of molecules

Question 13

what happens when a photoreceptor detects light

Answer 13

it releases less neurotransmitter

-photoreceptors in eye dont fire action potentials, only membrane potentials that will release neurotransmitter

Question 14

4 types of opsin

Answer 14

rods: rhodopsin
cones: short medium long

Question 15

adaptation

Answer 15

changes in sensitivity occur over time
-20 min for rod system to become fully active
large improvement rapidly

Question 16

sensitivity

Answer 16

ability to detect a signal
rods lose detail bc of aggregation
rods are able to detect with low amount of light (all aggregate together for neural signal)
-cones arent as sensitive because they dont aggregate and wont fire signal

Question 17

acuity

Answer 17

amount of detail, cones know where light is coming from because of no aggregation

Question 18

spatial summation

Answer 18

signals come into neuron at differnt times but post-synaptic will overlap and add up