L8 - action potentials

Question 1

golgi staining

Answer 1

only stain some neurons

Question 2

what did golgi think about the NS compared to Cajal

Answer 2

golgi thought the NS was continuous

Cajal correctly identiified the NS as individual ‘contigious’ neurons and saw they were connected by axons

Question 3

describe the monosynaptic stretch reflex

Answer 3

specialised ending/muscle spindle sends signal down sensory nerve 
Glutamate neurotransmitter released
spinal cord AMPA receptor
ACh released
signal down motor nerve
nicotinic receptor 
muscle contraction

Question 4

hippocampus is involved in

Answer 4

learning
memory
spatial navigation

Question 5

hippocampus means

Answer 5

seahorse

Question 6

how do you make hippocampal recordings

Answer 6

in vitro - slices

in vivo - implant electrodes

Question 7

ipsilateral neurons

Answer 7

same side of brain

Question 8

contralateral neurons

Answer 8

other side of brain

Question 9

how do CA1 pyr neurons talk to both ipsilateral and contralateral neurons

Answer 9

via axons

Question 10

terminal bouton

Answer 10

specialised pre-synaptic terminal at end of axon

Question 11

what allows APs to propagate everywhere and activates all synapses

Answer 11

APs clone themselves and split at branches

think tree diagram

Question 12

synaptic vesicles

Answer 12

balls of lipid membrane

Question 13

antiporter

Answer 13

transports neurotransmitter into vesicle via proton

e.g. H+ exchange antiporter

Question 14

role of SNARE proteins

Answer 14

mediate vesicle fusion with target membrane-bound compartment

Question 15

where is v-SNARE found

Answer 15

on vesicle

Question 16

where is t-SNARE found

Answer 16

on pre-synaptic plasma membrane

Question 17

3 proteins that make up SNARE complex

Answer 17

SNAP-25 and syntaxin on t-SNARE

Synaptobrevin on v-SNARE

Question 18

overall mechanism of botox

Answer 18

targets synapses that release ACh and interferes with SNARE proteins

Question 19

synaptotagmin

Answer 19

protein in vesicle membrane
important for dockin
Ca2+ binding domains

Question 20

probability of release (Pr)

Answer 20

APs do not always trigger release of neurotransmitter

Question 21

Pr ranges from

Answer 21

0-1

Question 22

effect of Pr on synaptic strength

Answer 22

if Pr increases then synaptic strength increases

Question 23

Pr = 0

Answer 23

no synaptic communication

Question 24

equation for calculating average Pr of population

Answer 24

no of synapses that are active on each trial / no of synapses in total population

Question 25

what is a good pr estimate

Answer 25

if a pair is connected by 1 synapse

Question 26

how do you change Pr

Answer 26

alter pre-synaptic Ca2+ entry | e.g. blockers

Question 27

short term synaptic plasticity

Answer 27

short lived change in strength of synaptic coupling that reflects on prior activity of the synapse

Question 28

what is a mossy fibre

Answer 28

a class of axon

Question 29

what makes up the trisynaptic loop

Answer 29

perforant path (PP) mossy fibre pathway (MFP) Schaffer-collateral commissural pathway (SCCP)

Question 30

synapses with low Pr

Answer 30

exhibit Paired Pulse Faciliation (PPF)

Question 31

synapses with high Pr

Answer 31

exhibit Paired pulse depression (PPD)

Question 32

PPF

Answer 32

Paired Pulse Facilitation when post synaptic potentials following arrival of an impulse are increased due to that following a prior impulse a form of short-term synaptic plasticity

Question 33

PPD

Answer 33

paired pulse depression form of short term synaptic plasticity when the second post synaptic potential decreases

Question 34

what is the effect of reducing Ca2+ on Pr and PPD

Answer 34

reducing Ca2+ reduces Pr | therefore eliminates PPD