Lecture 17: Synaptic Plasticity Part I

Question 1

Name the 3 variables that characterize quantal release.

Answer 1

The number of release sites (N)
Probability of quantal release (p)
The size of quantal response (q)

Question 2

What are the morphological correlates of N, p and q?

Answer 2

N: number of active zones

p: number of docked vesicles
q: response to a single vesicle

Question 3

Names the 2 sites of expression and describe them.

Answer 3

Presynaptic: change in amount of transmitter released
Postsynaptic: changes in sensitivity in response to transmitter released.

Question 4

Summation is only the temporal integration of synaptic inputs due to __________.
Also, what is this known as?

Answer 4

passive properties. Time constant tau

Question 5

An increase in synaptic strength when action potentials occur in rapid succession is known as?

Answer 5

Synaptic facilitation or paired pulse facilitation (PPF)

Question 6

What is the synaptic facilitation the result of?

Answer 6

prolonged calcium elevation (residual calcium hypothesis)

Question 7

What is the target of action on synaptic facilitation?

Answer 7

synaptotagmin

Question 8

Describe synaptic depression?

Answer 8

Reduction in synaptic strength during successive APs. Results from progressive depletion of vesicle pool

Question 9

Rate of depression depends on what?

Answer 9

Amount of transmitter released

Question 10

Calcium channels, AP waveform and neuromodulators can alter __________ at presynaptic terminal.

Answer 10

calcium influx

Question 11

When an animal becomes less responsiveness to repeated occurrences of a stimulus, this is called what?

Answer 11

Habituation

Question 12

What is sensitization?

Answer 12

Generalization of an aversive response to a noxious stimulus to other non-noxious stimuli

Question 13

In a gill motor neuron, sensitization results from activation of the serotonergic modulatory interneuron, which in turn does what?

Answer 13

increases the EPSP at the motor neuron (heterosynaptic)

Question 14

Describe the short term sensitization activation cascade. involving PKA.

Answer 14

5-HT activates Adenylyl-cyclase, which increases cAMP and then PKA.

Question 15

What are the 2 effects of PKA?

Answer 15

• Closes K+ channels, leading to broader spikes and more Ca2+ influx = more transmitter release
• increases the release of neurotransmitter

Question 16

Describe the long term sensitization.

Answer 16

PKA also phosphorylates CREB

Question 17

CREB stimulates ________ expression, which keep PKA persistently active.

Answer 17

ubiquitin hydrolase

Question 18

Name the characteristics of early LTP.

Answer 18

• blocked by protein kinase inhibitors

- not blocked by protein synthesis inhibitors

Question 19

Name the characteristics of late LTP

Answer 19

blocked by translational inhibitors

Question 20

What are the similarities between changes in synaptic transmission in Aplysia and LTP in mammals?

Answer 20

• Early, transient phase that relies on protein kinases to produce post-translational changes.
• Long lasting phases that need changes in gene expression.

Question 21

NMDAR dependent LTP is a __________ of synaptic plasticity.

Answer 21

long-lasting form

Question 22

NMDAR dependent LTP requires activation of ________ by presynaptically released glutamate while postsynaptic membrane is significantly depolarized.

Answer 22

NMDARs

Question 23

T/F: The rise is postsynaptic Ca2+ concentration activates intracellular signaling cascades that include protein kinases.

Answer 23

True

Question 24

Maintenence of late LTP requires __________.

Answer 24

Synthesis of new proteins

Question 25

LTP is accompanied by enlargements of ___________

Answer 25

dendritic spines (and associated postsynaptic densities)

Question 26

_________ is crucial for NMDAR-LTP:links receptor to CaMKII-alpha

Answer 26

Ca2+ influx

Question 27

LTP-mechanisms may convert __________ to active mode via AMPAR insertion

Answer 27

silent synapses

Question 28

Early LTP mostly depends on ___________. Late LTP depends on new ____________.

Answer 28

phosphorylation, gene expression

Question 29

LTP maintenance remodels the ___________

Answer 29

dendritic spine

Question 30

Consolidation of ________ requires a symphony of signaling mechanisms and on Translation and Transcription

Answer 30

late-LTP

Question 31

LTP consolidation requires _______

Answer 31

mTOR

Question 32

34. Natural C-fiber stimulation induces _______ in dorsal horn neuron

Answer 32

LTP