L2

Question 1

what are the primary cells of the retina

Answer 1

rods and cones

Question 2

name all the cells in the retina

Answer 2

retinal ganglion cells, amacrine cells, bipolar cells, horizontal cells, road and cones

Question 3

cone mediated vision is called

Answer 3

phototopic

Question 4

what is phototopic vision

Answer 4

high acuity colour vision in good illumination

Question 5

what is rod mediated vision called

Answer 5

scotopic vision

Question 6

what is scotopic vision

Answer 6

poorer acuity achromatic vision in low light levels

Question 7

where are the rods and the cones located on the retina

Answer 7

cones are at the fovea and rods are in the periphery

rods are fairly evenly distributed in the periphery

Question 8

explain convergence in terms of rods and cones

Answer 8

cones have low convergence therefore they have high spatial resolution

rods have high convergence

Question 9

other than rods and cones, what other cells are light sensitive

Answer 9

intrinsically photosensitive retinal ganglion cells (ipRGC)

Question 10

how do intrinsically photosensitive retinal ganglion cells (ipRGC) detect light

Answer 10

these cells utilize the photopigment melanopsin which is maximally sensitive to blue light

these cells have connections to the suprachiasmatic nucleus and are essential for entraining circadian rhythms

Question 11

how do intrinsically photosensitive retinal ganglion cells (ipRGC) keep us in time with the day night cycle

Answer 11

they send signals to the brain so that during the day they govern the production of cortisol and melatonin at night

Question 12

where are intrinsically photosensitive retinal ganglion cells (ipRGC) located in the retina

Answer 12

on the bottom section as this is where blue light from the sky would fall

Question 13

why don’t we see our blind spot where the optic nerve is

Answer 13

because of top down processing

When we close one eye you should see a blind spot. You don’t see this because our brain is completing the image by using other information and guessing what should be these.

Question 14

what is an excitatory and inhibitory neurotransmitter

Answer 14

glutamate = EPSP (depolerisation)

gabba = IPSP (hyperpolarisation)

Question 15

which cells in the retina release gabba

Answer 15

amacrine and horizontal cells

Question 16

what do retinal ganglion cells, bipolar cells, rods and cones release (in terms of neurotransmitter)

Answer 16

glutamate

Question 17

what is simultaneous contrast

Answer 17

it is the 2 gray squares where one looks darker than the other

Question 18

why does simultaneous contrast happen

Answer 18

because of lateral inhibition/opponent processing

Question 19

what are mach bands

Answer 19

when you have strips going from eg dark blue to light blue you interpret seeing a light and dark band when the colour changes

this happens because of lateral inhibition/opponent processing

Question 20

what is the function of lateral inhibition

Answer 20

The function of lateral inhibition is to enhance contrast to help the nervous system resolve edges of objects

Question 21

the quality of energy changes depending on what

Answer 21

frequency

Question 22

what wavelengths of light are we aware of

Answer 22

visible light (400 - 700nm)

this is because these are the only frequency’s that the nervous system is able t interpret and it does so as colour

Question 23

what are the 3 colours are cones most sensitive to

Answer 23

blue, green and red

Question 24

what wavelengths are the 3 different cones each most maximally sensitive to

Answer 24

blue = 420 
green = 534
red = 564

Question 25

what % of males and females are red green colour blind

Answer 25

5-10% of males and 0.1% of females

Question 26

what is the most common form of colour-blindness

Answer 26

deuteranomaly (when you dont see green very well)

Question 27

what is protanopia

Answer 27

it is the second most common form of colour-blindness which is when you cant see red

Question 28

how do we see make colours than just red, green and blue

Answer 28

opponent processing

Question 29

why do you get colour afterimage when you steer at certain colours for a sustained period of time

Answer 29

because when you initially look at the colour you get rapid firing, this dies out over time which means that when you eventually look away you end up with an after image

Question 30

what is homeostasis

Answer 30

any self regulating process by which an organism tends to maintain stability while adjusting to conditions

Question 31

how does opponent processing relate to homeostasis

Answer 31

for the example of body temp…

when you get cold you start to shiver which inhibits your ability to sweat

Question 32

what is approach avoidance

Answer 32

it is an example of opponent processing in motivation

it arises from competition between the drives to pursue the reward and to avoid harm

eg you want to eat the cake but you don’t want to go to the dentist