lecture 15

Question 1

sensory receptors

Answer 1

specialized cellls that transduce sensory energy into neural activity

Question 2

sensation

Answer 2

registration of physical stimuli from environment by sensory organs

Question 3

perception

Answer 3

subjective interpretation of sensations by the brain
- visual experience is not an objective reproduction of what is out there: subjective contruction of reality manufactured by the brain

Question 4

light

Answer 4

electromagnetic energy that we see

range about 400nm-700nm

Question 5

structure of eye

Answer 5

cornea- clear outer covering
iris- opens and closes to allow more or less light in
lens- focuses light
retina- light energy initiates neural activity

Question 6

retina

Answer 6

the light sensitive surface at the back of the eye

- consists of neurons and photoreceptor cells to translate light into APs and discriminate wavelengths

Question 7

fovea

Answer 7

region at hte centre of the eye that is specialized for high acuity
- receptive field at the center of eyes visual field

Question 8

blind spot

Answer 8

region of retina where axons form the optic nerve and leave the eye

• has no photoreceptors
• dont notice because your brain compensates for it

Question 9

rods

Answer 9

sensitive to low levels of light, night vision
only one type of pigement
- more numerous than cones

Question 10

cones

Answer 10

highly responsive to bright light, color

3 types of pigement, concentrated in the fovea

Question 11

distribution of retinal receptors

Answer 11

more red and green than blue

Question 12

types of retinal neurons

Answer 12

bipolar: receives input from photoreceptors
horizontal: links photoreceptor and bipolar cells
amacrine: links bipolar and ganglion cells
retinal ganglion: gives rise to optic nerve

Question 13

magnocellular cells

Answer 13

large, receives input from rods

sensitive to light and movement

Question 14

parvocellular cell

Answer 14

small, receives input from cones

sensitive to color

Question 15

visual pathwasy

Answer 15

axons from nasal half cross over to contralateral
axons from temporal half remain in same side
- info from left visual field goes to right vice versa

Question 16

optic chiasm

Answer 16

junction of the optic nerves from each eye

Question 17

route 1- geniculostriate system

Answer 17

projections from the retina go to the LGN nucleus to the visual cortex
(LGN–> striate –> other areas)

Question 18

route 2- tectopulvinar system

Answer 18

projections from retina to superior colliculus to pulvinar (thalamus) to parietal and temporal visual areas
(superior colliculus–> pulvinar–> other areas)

Question 19

route 3- retinohypothalamic tract

Answer 19

synapses in tiny suprachiasmic nucleus in hypothalamus

- role in regulating circardian rhytms in pupillary reflex

Question 20

lateral geniculate nucleus

Answer 20

right LGN- input from right half of each retina

left LGN-input from left half of each retina

Question 21

LGN layers

Answer 21

M cells: layers 1 and 2- movement

P cells: 3 and 6- color and form

Question 22

striate cortex

Answer 22

primary visual cortex- highly myelinated

two visual paths: one to parietal one to temporal

Question 23

dorsal visual stream

Answer 23

projects to parietal cortex- the how pathway

- how an object is to be guided

Question 24

ventral visual stream

Answer 24

projects to temporal cortex- the what pathway

- identifies an object

Question 25

what cells are in the tectopulvinar path

Answer 25

magnocellular cells from retina project to S.C which sends to pulvinar
medial pulvinar: sends cxns to parietal lobe
lateral pulvinar: sneds cxns to temporal lobe
- provides info about location
- blind sight

Question 26

occipital cortex

Answer 26

composed of 6 visual regions with varying degrees of complexity

• V1: striate cortex receives input from LGN
• V2-V5: secondary visual cortex

Question 27

heterogenous layers

Answer 27

blob: V1- regions in the visual cortex that contain color-sensitive neurons
interblob: V1- region that seperates blobs, participates in form and motion

Question 28

stripes in V1

Answer 28

thick: receive info from movement sensitive interblobs
thin: receive info from color sensitive blobs
pale: receive info from form sensitive interblobs