Lecture 18: Synaptic Plasticity Part II

Question 1

__________ is the opposing process to LTP

Answer 1

Long term depression (LTD)

Question 2

T/F: LTD may serve to counteract otherwise steadily decreasing levels of potentiation.

Answer 2

False, steadily increasing

Question 3

LTP can be actively reversed by _________ stimulation of NMDA-Rs, which leads to LTD.

Answer 3

low-frequency

Question 4

LTP results from brief, high frequency stimulation, but LTD occurs when a pathway id stimulated at a _______ for a __________.

Answer 4

low rate, long time

Question 5

LTD is blocked by what two antagonists?

Answer 5

NMDAR and calcineurin

Question 6

What are 3 main characteristics that LTP and LTD share?

Answer 6

• lasts for several hours
• input specific
• can erase the increase in EPSP size

Question 7

LTD is initiated by what?

Answer 7

small and slow increases in Ca2+ trigger depression

Question 8

LTP is initiated by what?

Answer 8

large and fast trigger potentiation

Question 9

LTD results mainly from a decrease in _____________.

Answer 9

postsynaptic AMPA receptor density

Question 10

LTD results from activation of what?

Answer 10

Ca2+ dependent phophatases which internalizes AMPARs

Question 11

Different increases in Ca2+ concentration determine threshold and extent and direction of ___________.

Answer 11

synaptic strengthening

Question 12

Hippocampal LTD depends on?

Answer 12

NMDA receptors
mGluRs
endocannabinoids

Question 13

AMPA receptor trafficking and kinase vs. phosphatase activity defines ________.

Answer 13

LTP vs. LTD

Question 14

Fragile X is caused by a mutation in the _______ gene

Answer 14

FMR1

Question 15

FMRP binds and transports __________.

Answer 15

mRNAs

Question 16

Loss of FMRP leads to what?

Answer 16

excessive dendritic arborization

Question 17

Impaired synaptic plasticity can result in what?

Answer 17

• Increased mGluR LTD
• Decreased LTP
• Immature dendritic spine architecture

Question 18

Deficits in LTP in Fragile X are related to what?

Answer 18

mGluR dependent translational mechanisms. mGluR mediated events will be enhanced or absent Blocking mGluR 1 and 5 will rescue these deficits.

Question 19

What drug could prove useful in finding a target in Fragile X?

Answer 19

Fenobam

Question 20

PKMζ is an atypical ______.

Answer 20

PKC. Lacks a regulatory subunit and is autonomously activated once it’s translated.

Question 21

PKMζ is sufficient to _____ LTP

Answer 21

induce

Question 22

PKMζ moves _________ to the synapse.

Answer 22

AMPARs

Question 23

PKMζ is inhibited by ZIP. What does ZIP do?

Answer 23

Reverses late-LTP and causes established memory decay.