CH 9

Question 1

sensory receptors

Answer 1

specialized cells that convert sensory energy (light) into neural activity

Question 2

how is sensory info coded

Answer 2

by action potentials that travel along peripheral nerves to the CNS

Question 3

how can the presence of a stimulus be encoded?

Answer 3

by an increase or decrease in discharge rate.

Question 4

what does the neocortex represent?

Answer 4

the sensory field of each modality: vision, hearing, touch, smell, taste

Question 5

what is a topographic map?

Answer 5

a neural-spatial representation of how high sensation is on each part of body

Question 6

electromagnetic energy

Answer 6

light: 400-700 nanometers visible to humans

Question 7

cornea

Answer 7

clear outer covering of eye

Question 8

iris

Answer 8

opens and closes to let light in

Question 9

lens

Answer 9

focuses light, bends to accommodate near and far objects

Question 10

retina

Answer 10

where energy initiates neural activity

Question 11

retina

Answer 11

covers back of eye, neurons and photoreceptor cells, translates light to action potentials, discriminates wavelengths

Question 12

acuity of visual field

Answer 12

vision better in center field than in view margin or periphery

Question 13

blind spot

Answer 13

optic disc: axons form nerve and leave eye, where blood vessels enter and exit -> no photoreceptors here

Question 14

papilledema

Answer 14

swollen optic disc, due to high intracranial pressure or inflammation -> can cause vision loss

Question 15

rods

Answer 15

more in eye than cones, sensitive to dim light, night vision, one pigment

Question 16

cones

Answer 16

bright light, colour, only in fovea, 3 types pigment

Question 17

bipolar cells

Answer 17

receives input from photoreceptors

Question 18

horizontal cell

Answer 18

links photoreceptors and bipolar cells

Question 19

amacrine cell

Answer 19

links bipolar cells and ganglion cells

Question 20

retinal ganglion cell (RGC)

Answer 20

gives rise to the optic nerve

Question 21

ganglion cell: Magnocellular cell (M-Cell)

Answer 21

large, gets input from rods, sensitive to light and moving stimuli

Question 22

ganglion cell: parvocellular cell (P-cell)

Answer 22

small, gets input from cones, sensitive to colour

Question 23

optic chiasm

Answer 23

axons from inside (nasal) half of retina cross to opposite side of brain, outer half of retina goes to same side of brain so L-> R brain R-> L brain

Question 24

what are the 3 route to the visual brain

Answer 24

geniculostriate system, tectopulvinar system, retinohypothalamic tract

Question 25

geniculostriate system

Answer 25

retina to lateral geniculate nucleus to visual cortex

Question 26

tectopulvinar system

Answer 26

retina, to superior coliculus to pulvinar (thalamus) to parietal and temporal visual areas

Question 27

retinohypothalamic tract

Answer 27

synapses in tiny suprachiasmatic nucleus in the hypothalamus -> regulates circadian rhythms and pupillary reflexes

Question 28

striate cortex

Answer 28

primary visual cortex: 2 visual paths 1: goes to vision regions of parietal lobe 2: goes to vision regions of temporal lobes

Question 29

dorsal stream

Answer 29

originates in occipital cortex, projects to parietal cortex (the how pathway) (how action is carried out)

Question 30

ventral visual stream

Answer 30

originates in occipital cortex, projects to temporal cortex (the what pathway) (identifies things)

Question 31

geniculostriate pathway

Answer 31

Lateral geniculate nucleus (thalamus): Right : input from R half of retina Left: L half of retina, has 6 layers

Question 32

6 layers of later geniculate nucleus

Answer 32

1,4,6: input from contralateral retina 2,3,5: input from ipsilateral retina 1,2: input from magnocellular cells 3-6: input from parvocellular cells

Question 33

tectopulvinar pathway

Answer 33

magnocellular cells from retina project to superior colliculus -> sends info to pulvinar region of thalamus (is the where pathway) (takes in info about where things are/location)

Question 34

tectopulvinar pathway (regions of thalamus sends things to)

Answer 34

medial pulvinar: sends connections to parietal lobe lateral pulvinar: sends connections to temporal lobe

Question 35

occipital cortex

Answer 35

6 visual regions primary visual cortex: (striate cortex) receives input from lateral geniculate nucleus. secondary visual cortex: (v2-V5) extrastriate cortex) visual cortical areas outside the striate cortex

Question 36

heterogeneous layer (Blob V1)

Answer 36

region in the visual cortex, contains color sensitive neurons

Question 37

heterogeneous layering (interblob V1)

Answer 37

region that separates blobs -> participates in perception of form and motion