Topic 2: Neural Foundations Part 2

Question 1

resting potential and membrane potential

Answer 1

more positive outside
more negative inside
difference in potential of 70mv

Question 2

chemical gradients

Answer 2

more na (sodium) outside
more K (potassium) inside

Question 3

action potentials

Answer 3

occur at thresholds of 55 mv 
all or none phenomenon
constant amplitude - 100mv
constant time course - 1 or 2 ms 
followed by refractory period (5 ms)

Question 4

self regenerating propogation

Answer 4

action potentials travel down to axons to synapses without losing their strength

Question 5

neurotransmitter
synaptic cleft
receptors

Answer 5

signal from pre to post synaptic cell is chemical
gap between pre and post synaptic cell
reception of neurotransmitter by post synaptic cell causes post synaptic potential (PSP)

Question 6

Post synaptic potential

Answer 6

originate at synapses
graded (large or small)
propagate electronically to axon hillock
depend on neurotransmitter and receptors

Question 7

EPSP

IPSP

Answer 7

increase in positive charge inside the cell

increase the negative charge inside the cell

Question 8

PSP vary in

Answer 8

size: how much neurotransmitter and how many receptors
sign: type of transmitter and receptors
speed: ionotropic of metabtropic receptors

Question 9

temporal summation

spatial summation

Answer 9

PSPs from different times can sum together at the axon hillock
-PSPs from different synapses sum together at the axon hillock

Question 10

integrate and fire (neural function)

Answer 10

the inputs are graded (vary along a continuum)

• at each point in time, the neuron sums all of its inputs ad fires or not
• output is all or none

Question 11

center surround receptive field

Answer 11

retinal ganglion cells
-on center and off surround
off center on surround
if the light is focused on the on area then there will be firing of the cell - cant cover the whole thing or it will inhibit
emphasize edges to give us info about external environment

Question 12

lateral inhibition

Answer 12

inhibits the action of the neighbouring neuron when it itself is excited
-brain pinpoints where the exact stimulus is coming from

Question 13

superior colliculus

Answer 13

regulates involuntary eye movements

Question 14

dorsal stream

ventral stream

Answer 14

where/how pathway (parietal lobe)

-what/why pathway (temporal lobe)

Question 15

ocular dominance columns

Answer 15

stripes when visual field (left and right) overlap

-centre of visual field

Question 16

orientation columns

Answer 16

represent light at same locaiton but different orientations