2 - Synaptic Plasticity

Question 1

T/F. The underpinning learning and memory processes, including motor learning and skill acquisition, is believed to reside in the experience-dependent modification of the synapse strength between neurons.

Answer 1

True

Question 2

T/F. There are fundamental processes that change the strength of the synapse between neurons.

Answer 2

True

Question 3

Action potential:

Answer 3

How it is generated

Question 4

How do neurons communicate with each other?

Answer 4

Using short spikes of electrical activity (AP)

Question 5

How are APs possible?

Answer 5

Cell membranes are semipermeable to ion flow, and voltage-gated channels in the membrane control this permeability

Question 6

What is the sequence of APs?

Answer 6

1) Cells at rest is permeable primarily to K+ ions, cell near K+ reversal potential (-80mV)
2) Small amount of input current raises cell potential
3) Voltage-gated Na+ channels ope, allowing more Na+ in, and opening more channels
4) Voltage spikes Na+ channels deactivate, and K+ open returning the cell to rest

Question 7

What is synaptic strength?

Answer 7

Size of the post-synaptic potential

Question 8

What are post-synaptic potentials?

Answer 8

Change in voltage in the post-synaptic cell caused by a SINGLE spike in the presynaptic cell

Question 9

What units are post-synaptic potentials are in?

Answer 9

mV

Question 10

Can post-synaptic potentials be either both positive (excitatory) or negative (inhibitory)?

Answer 10

Yes

Question 11

EPSP?

Answer 11

Pre-synaptic cell wants to help the post-synaptic cell fire a spike.

Question 12

IPSP?

Answer 12

Pre-synaptic cell wants to prevent the post-synaptic cell from firing a spike.

Question 13

Synaptic strength?

Answer 13

Used to store important info in the NS.

Question 14

The size principle of motor activation?

Answer 14

Motor units come in varying sizes

• Small motor units producing the least amount of force but least susceptible to fatigue
• Larger motor units gets fatigue easier

Question 15

Synaptic strength is encoded by:

Answer 15

Motor neuron size

Question 16

Synaptic strength determines:

Answer 16

Recruitment order

Question 17

Short-term synaptic plasticity

Answer 17

Synapses change strength a little bit as they are used, but the connection remains relatively stable

Question 18

Longer-term synaptic plasticity

Answer 18

Basis of learning and memory

Question 19

Aplysia model of learning

Answer 19

1) Gill withdraws the siphon when siphon touched. Responds less with time.
2) Response heightened by noxious stimuli to the tail/ Serotonergic activation of PKa, makes K+ channels deavtice in the sensory-motor synapse.
3) Serotonin - important molecule modulating motor activity even in humans

Question 20

Long-term potentiation

Answer 20

Induced by high frequency stimuli to pre-synaptic cell, or paired stimulate to pre and post-synaptic cells whiner pre comes before post.
Addition of AMPA receptors to post-synaptic membrane.

Question 21

Long-term depression

Answer 21

induced by low frequency stimuli to pre-synaptic cell, or post before pre pairing.
Removal of AMPTA receptors from post-synaptic cell.