Brain Mapping (Week 3)

Question 1

receptive field

Answer 1

part of sensory world which a neuron responds to

Question 2

big receptor field pros and cons

Answer 2

pros: covers larger area (no position variance problem)
cons: non specific

Question 3

small receptor fields pros and cons

Answer 3

pros: differentiates between specific information
cons: only covers small area, position variance

Question 4

position variance

Answer 4

being able to identify an object anywhere in space

Question 5

somatosensory receptive fields

Answer 5

areas of bodies surface that respond to sensory stimuli

Question 6

where are the smallest somatosensory RF

Answer 6

fingertips

Question 7

where are the largest somatosensory RF

Answer 7

thigh/calf

Question 8

what dictates where on the body there are small vs large RF

Answer 8

sensitivity of that area (ex. lots of dexterity needed in fingers -> higher sensitivity -> smaller more specific RF)

Question 9

visual receptor field

Answer 9

area of visual space that processes visual stimuli

Question 10

degrees of visual angle

Answer 10

measurement for visual receptive field; how large an object appears to be in your field of view.

Question 11

olfactory receptive field

Answer 11

mapped along dimension of # of carbons in a chain or size of molecules (small scale)

Question 12

numerical receptive fields

Answer 12

mapped along dimension of numerosity (respond to magnitude of things)

Question 13

where are numerical receptive fields often found

Answer 13

parietal and prefrontal neurons

Question 14

how does brain optimize receptive fields

Answer 14

many smaller adjacent RF send action potentials all to one larger RF

• communicate to each other via feedforward and feedback pathways

Question 15

topographic map

Answer 15

orderly representation of sensory space in the brain

Question 16

how are neurons arranged in topographic maps of the brain

Answer 16

disproportionately representative of world which allows greater sensitivity to parts that occupy more space

(ex. Fovea- part of the retina with high spatial resolution)

Question 17

what places in the brain have the most neurons

Answer 17

high sensitivity places

Question 18

Retinotopic Map

Answer 18

orderly representation of visual space/ hemifield; shows how light maps onto the back of the eye

Question 19

what part of the brain shows complete representation of visual hemifield

Answer 19

V1 (primary visual cortex)

Question 20

what happens to the complete representation of the hemifield as you move forward in the brain

Answer 20

more localized specialization

Question 21

tonotopic map

Answer 21

ordly representation of sound/tone frequency; respond to different frequency sound waves

Question 22

somatotopic map

Answer 22

ordlery representation of body surface for specific area of the brain

Question 23

fine-grained maps

Answer 23

large number of neurons; small receptive fields

Question 24

coarse grained maps

Answer 24

small number of neurons; large receptive fields

Question 25

how does the brain group neurons effiecently

Answer 25

neurons processing nearby sensory space group together bc they interact more often and that reduces wiring

Question 26

reference frame

Answer 26

a coordinate system used to represent the position of an object

Question 27

how do you specify a position in a reference frame

Answer 27

with regards to the position of a reference point

Question 28

2 classes of reference frames

Answer 28

egocentric and allocentric reference frames

Question 29

subclasses of egocentric reference frames

Answer 29

- eye centered/ retinoscopic: eye is origin of coordinate system - head centered: head is origin of coordinate system -body centered: body or part of body is origin of coordinate system (ex. motor system)

Question 30

subclasses of allocentric reference frames

Answer 30

-object centered - world centered (street map)

Question 31

how can you test what reference field a neuron has

Answer 31

move stimulus and see how the receptive field moves

Question 32

what type of reference frame does the hippocampus have

Answer 32

allocentric

Question 33

what type of reference frame does the parietal cortex have

Answer 33

egocentric

Question 34

how is information transformed between allocentric and egocentric between hippocampus and parial lobes

Answer 34

PCC (posterior cingulate cortex) and RSC (retrosplenial cortex) which is a brain hub

Question 35

how does the RSC help with allocentric-egocentric transformations

Answer 35

has both allocentric cells and egocentric cells- consistent with the role in spatial transformations

Question 36

head direction cells

Answer 36

cells that respond to our directional heading in the horizontal plane (which way we are facing): needed for allosteric/ egocentric transformation

Question 37

how do signals from head direction cells work

Answer 37

certain neurons fire when head is facing a certain angle/ direct but not at other times

Question 38

why is there a connection between hippocampus and parietal cortex

Answer 38

transforms between egocentric and allocentric during navigation; connects self to our surroundings/ place yourself in your allosteric view of the setting

Question 39

what pathway do sensory motor transformations go along

Answer 39

"How" pathway at the top of the brain; how to use an object and where it is

Question 40

what helps transform egocentric information from the occipital love to egocentric information in the primary motor cortex

Answer 40

parietal lobe

Question 41

process of transmitting info from sight/ other senses to motor cortex

Answer 41

sensorimotor transformation

Question 42

sensorimotor transformation steps

Answer 42

1) receive info about location of visual target in eye centered coordinates 2)target location remapped into joint coordinates so you can move arm to corresponding location * 1 or more transformation steps

Question 43

mathematical way brain finds hand centered position of the target

Answer 43

subtract eye centered hand position from eye centered target position

Question 44

what i the PPC function in tranformation

Answer 44

translator for different reference frames across brain

Question 45

2 main important transformations

Answer 45

eye centered - body centered (both egocentric) egocentric - allocentric