Synaptic Plasticity part II

Question 1

LTD (Long-term depression) is the opposite process to what?

Answer 1

LTP

Question 2

Definition of LTD?

Answer 2

A mechanism to remove potentiated synapses from the network

Question 3

LTP can be actively reversed by _______ stimulation of NMD-Rs. leading to LTD

Answer 3

Low-Frequency

Question 4

While LTP results from brief, high frequency stimulation, LTD occurs when?

Answer 4

Pathway is stimulated at a low rate (0.5-5 Hz) for a long time (10-15 min)

Question 5

LTD is blocked by what antagonist?

Answer 5

NMDAR

Calcineurin (PP2B) antagonist

Question 6

What are some characteristics of LTD?

Answer 6

• Lasts for several hours
• Input specific
• Is able to erase the increase in EPSP size, resulting from LTP.

Question 7

Whether LTP or LTD is initiated depends on the nature of the_____ signal.

Answer 7

Ca2+

Question 8

Small and slow increase in Ca2+ triggers?

Answer 8

Depression (LTD)

Question 9

Large and fast increases triggers?

Answer 9

Potentiation (LTP)

Question 10

LTD results mainly from a decrease in postsynaptic _____ receptor density.

Answer 10

AMPA

**Although a decrease in presynaptic neurotransmitter release may also play a role.

Question 11

LTD results from activation of Ca2+ dependent phosphateses such as Calcineurin (PP2B) that dephosphorylates the target proteins. In turn causing?

Answer 11

Internalization of AMPARs

Question 12

Increases in Ca2+ concentration determines ?

Answer 12

Threshold, the extent and direction of the synaptic strengthening.

Question 13

Amount of calcium influx in the postsynaptic cell largely determines whether…

Answer 13

LTD or LTP occurs

Question 14

If the synapse has been subjected to LTP, what is the system to maintain synaptic homeostasis?

Answer 14

The threshold is raised, increasing the probability that a low calcium influx will yield LTD.

Question 15

Hippocampal/cortical LTD can depend on?

Answer 15

• NMDA receptors,
• Metabotropic glutamate receptors
• Endocannabinoids.

Question 16

FXS is caused by mutation in the ____ gene.

Answer 16

FMR1

Question 17

FMRP binds and transports what?

Answer 17

mRNAs

Question 18

Loss of FMRP leads to excessive?

Answer 18

Dendritic arborization

Question 19

Phenotype of the FMR1 KO mouse outcome was?

Answer 19

• Increased activity in open field test
• Reduced anxiety/trace fear conditioning
• Impaired synaptic plasticity
• Increased auditory seizure propensity