3b - Sensory Contribution

Question 1

what are the functions of the vestibular system?

Answer 1

detecting head motion and orientation

Question 2

what are the components of the vestibular system?

Answer 2

otolith and semilunar canals

Question 3

how does the vestibular system detect changes and turn them into signals?

Answer 3

• ## hair cells are deflected and depending on whether they deflect towards or away from the kinocilium, that dictates if more or less action potentials are fired

Question 4

what happens when deflection of hair cells is towards the kinocilium?

Answer 4

ion gates are opened more and that leads to more rapid action potentials

Question 5

what happens if deflection is away from the kinocilium?

Answer 5

ion gates` are closed and that leads to less frequent action potentials

Question 6

what is the function of otoliths?

Answer 6

they sense linear head accerleration

Question 7

what are the 2 components otoliths?

Answer 7

saccule and utricle

Question 8

what type of motion does each component of the otolith detect?

Answer 8

saccule detects vertical acceleration

utricle detects horizontal acceleration

Question 9

otolithic membranes contain _________ ________. hair cells grow up into this membrane and are displaced by the ________ _______ during motion. this triggers the mechanism that leads to action potentials

Answer 9

otoconia stones (both blanks)

Question 10

what are the 3 locations of semicircular canals?

Answer 10

posterior, superior, horizontal

Question 11

what do semicircular canals detect?

Answer 11

• turning and tilting of the head

- angular acceleration

Question 12

semicircular canals are filled with a thick fluid called ________, when the body moves, the ______ lags behind it because of its inertia. this causes the hairs within the _______ to be displaced in the opposite direction to which the person moved

Answer 12

endolymph, endolymph, cupula

Question 13

def: electrodes are placed over the mastoid bones behind the ears

Answer 13

galvanic vestibular stimulation

Question 14

how does galvanic vestibular stimulation work?

Answer 14

• they activate the vestibular afferents
• this leads to the illusion of tilts and motion
• this makes the body tilt in the opposite direction as the illusion to keep it stable

Question 15

what are some parts of the eye? (5)

Answer 15

• pupil
• cornea
• retina
• fovea
• lens

Question 16

what is the function of the retina?

Answer 16

• contains photoreceptors which transduce light into electrical signals

Question 17

what is the part of the retina that allows the vision of fine details?

Answer 17

fovea

Question 18

why does the fovea allow for the vision of fine details?

Answer 18

it contains only cones, no rods

Question 19

the back of the retina has _____, which absorbs the light the is not captured by the retina

Answer 19

melanin

Question 20

what is the significance of the melanin behind the retina?

Answer 20

it stops light from reflecting back and distorting the image

Question 21

def: small, 5 degree, area that the eyes are focused on, predominantly contains cones, deals with fine details

Answer 21

central vision

Question 22

T or F: peripheral vision contains mostly cones

Answer 22

false, it contains mostly rods

Question 23

what are the 2 segments of the retina called?

Answer 23

1. nasal hemiretina

2. temporal hemiretina

Question 24

what visual field does the nasal hemiretina detect?

Answer 24

sees the lateral parts of the image

Question 25

what visual field does the temporal hemiretina detect

Answer 25

the inner parts of the image

Question 26

the nasal hemiretina crosses the ______ ______ and it propagates its impulse to the _________ brain hemisphere

Answer 26

optic chiasm, contralteral

Question 27

how many layers does the primary visual cortex have?

Answer 27

6

Question 28

def: light from specific location on the visual field hits the retina in specific parts. each specific part of the retina is mapped to a specific location in the visual cortex

Answer 28

retinotopic representation

Question 29

_________ ganglion and lateral _____ nucleus neutrons have tiny receptive fields, like pixels

Answer 29

retinal ganglion and lateral geniculate nucleus neurons

Question 30

_______ __ neurons are similar to retinal ganglion and LGN neurons

Answer 30

layer 4c

Question 31

def: cells in V1 that have elongated receptive fields, they sense the lines and edges of a particular orientation, they respond to bars of light and bars of dark on edges

Answer 31

simples cells

Question 32

def: cells with large receptive fields, sense lines and edges anywhere with any orientation, can also respond to moving bars of light

Answer 32

complex cells

Question 33

def: graph the level of activation of a neuron against the orientation of the stimuli

Answer 33

neuronal tuning curves

Question 34

what is the path of impulse from the eye to the primary visual cortex?

Answer 34

1. retinal ganglion neuron 2. lateral geniculate neuron 3. layer 4c 4. simple V1 5. complex V1

Question 35

def: helps determine the distance from an eye by calculating the disparity between the image obtained by each eye

Answer 35

binocular retinal disparity

Question 36

def: area of the brain that receives visual data related to motion. this region is more active with higher speeded motion. it projects to the medial superior temporal region

Answer 36

middle temporal regions (v5)

Question 37

def: receives data from multiple locations and separates them into 2 streams; self motion and object motion

Answer 37

medial superior temporal

Question 38

def: the light patterns and the changes in light patterns that go over a persons retina that allows them to perceive motion

Answer 38

optic flow for movement

Question 39

what kind of information can optic flow be used for?

Answer 39

- the change in movement patterns of light rays from the environment over a person retina allows for individuals to perceive motion - abrupt chnages in pattern correspond to boundaries and features in the environment

Question 40

def: calculates object image size and rate of its radial expansion on the retina to calculate its velocity

Answer 40

time to contact calculations

Question 41

def: feedback from muscle spindles in eyes as the eyes rotate to track an object

Answer 41

oculomotor vergence feedback

Question 42

what type of data does the ventral stream convey?

Answer 42

- tells you about the world in terms of objects and distances from each other, talks about details of an object - fine analysis of the visual scene and object recognition - uses object centered frame of reference

Question 43

what type of data does the dorsal stream convey?

Answer 43

- tells the brain about where an item is in respect to ones self, also provides data on how to interact with the world - guides movements and spatial characteristic of the environment - frame of reference is based on ones own body - tells you how to interact with things