Synaptic Plasticity

Question 1

Connectome?

Answer 1

Structural connectivity of nervous system

Question 2

Hebbian Modification?

Answer 2

Strengthens reciprocal connections between neurons that are active at the same time.

Question 3

Hebb’s rule?

Answer 3

Repetition of activity, cell A repeatedly exciting cell B, cell A’s efficiency increases due to metabolic changes and growth.

Neurons that fire together wire together.

Question 4

Long term potentiation?

Answer 4

Temporal, associative and specific.

Question 5

Temporal?

Answer 5

Summation of inputs, repetitive causing LTP

Question 6

Associative?

Answer 6

Stimulation of both strong and weak causes LTP of both, spatial summation.

Question 7

Specific?

Answer 7

Input specific, at one synapse isn’t propagated to adjacent

Question 8

Activation of post synaptic cell?

Answer 8

When membrane is depolarised, AMPA receptor activates, Mg block relieved from NMDA. High frequency stimulation causes repeat activation, hence LTP!

Question 9

How does calcium cause activation?

Answer 9

Calcium activates Protein kinase C, CaMKII.

Phosphorylate AMPA receptors. Increase insertion of new AMPA receptors.

CaMKII can catalyse itself.

Question 10

Presynaptic events of LTP?

Answer 10

Retrograde nitric oxide:

Calcium activates nitric oxide synthase, NO activates guanylyl cyclise cause cGMP, release of glutamate

Question 11

Late phase LTP?

Answer 11

Protein synthesis, CREB by CaMKII

Binding protein activated by phosphorylation be a number of kinases

Question 12

Stages of Memory

Answer 12

Acquisition
Consolidation
Recall

Question 13

Difference in early and late phase?

Answer 13

Early phase- AMPA receptors, NMDA. Diffusion of NO. Up to an hour.

Late phase- Morphological changes, protein synthesis, up to months.

Question 14

Long Term Depression?

Answer 14

Low frequency stimulation, 100 x 1Hz. Complete opposite, low level calcium activates phosphatases rather than kinases

Question 15

Morris Water Maze?

Answer 15

AP5-NMDA antagonist, blocks hippocampal LTP

Question 16

NMDA receptor antagonist?

Answer 16

Alcohol GABA agonist, disrupts theta rhythm hippocampal short term memory.

Chronic alcoholism, korsakoff syndrome, loss of recent memory and confabulation.

Question 17

Benzodiazepines?

Answer 17

GABA a indirect agonist, side effect to anxiolytics and sedative properties is anterograde amnesia

Question 18

Anticholinergics?

Answer 18

Scopolamine, muscarinic antagonist, suppresses theta waves and impaired spatial learning,

Question 19

Alzheimer’s drug?

Answer 19

Acetylcholinsterase inhibitors- Physostigmine

Question 20

What does calcium activated signal transduction cascades do?

Answer 20

Activate new protein synthesis from dendritically localised mRNAs

Then filter back to the cell body to stimulate new gene transcription CREB mediated, protein synthesis and recruitment of new proteins of the synapse

Question 21

Basal forebrain bundle from?

Answer 21

Medial septum to hippocampus, which regulates theta waves

Basal nucleus to cortex