Synapses and Plasticity Two

Question 1

What is the term that describes measuring synapse activity?

Answer 1

Electrophsyiology

Question 2

What does Electrophsyiology measure?

Answer 2

Either:

An AP
or
The current going through a receptor channel

Question 3

What are the two types of recording?

Answer 3

Extracellular recordings (Population recordings or Field Recordings)

and

Whole cell recordings / Patch clamping

Question 4

How is a Extracellular recording done?

Answer 4

Simulating electrode is placed in/on axons.
Recording Electrode is placed on a population of synapses.

The simulating electrode induces an action potential then the recording electrode measures current going through post synaptic receptors.

Question 5

What are some advantages and disadvantages of field recordings?

Answer 5

Advantage: Its simple

Disadvantage:

• General info for a large population of synapses
• Not specific

Question 6

What does FEPSP stand for?

Answer 6

Field Excitatory Post Synaptic Potential

Question 7

When a FEPSP is measured in a voltage potential graph, how is an influx of ions shown?

Answer 7

As a downwards dip. As AMPA activation results in loss of positive ions from the external environments potential

Question 8

What is a field recording useful for?

Answer 8

Evaluating normal baseline synaptic transmission potential

Question 9

Describe how patch clamping works

Answer 9

Stimulating electrode is placed on a neurons axon, while the recording electrode is placed within the post synaptic neuron.

Question 10

What does EPSC stand for?

Answer 10

Excitatory post synaptic current

Question 11

What sort of receptor is responsible for Excitatory post synaptic current?

Answer 11

AMPA

Question 12

Describe the appearance of a membrane potential recording for patch clamping, when theres a current inflow.,

Answer 12

It will always be negative from the baseline potential, regardless of ion charge.

Question 13

What can patch clamping measure?

Answer 13

AP of a cell
Ion Channel Currents
Measure synapse function in individual neurons

Question 14

What is highly unique feature of the brain?

Answer 14

Its plasticity - with regards to neurons

Question 15

What is the definition of synapse plasticity?

Answer 15

The ability of synapses to change their strength in response to specific stimulation

Question 16

In what way do synapses change their strength?

Answer 16

They become stronger of weaker from the basal strength.

Question 17

What is synaptic strength?

Answer 17

Amplitude of current generated in a synapse

Question 18

In what region of the brain is an excellent model for measuring synaptic plasticity?

Answer 18

Synaptic plasticity is normally measured in the hippocampus is thought to be the site of declarative (Explicit) memory.

Question 19

What is explicit memory?

Answer 19

Faces, Numbers, facts

Question 20

What is the advantage of using hippocampus slice preparations for measuring synaptic plasticity?

Answer 20

Stay alive for many hours

Relatively Simple architecture

Question 21

Describe the trisynaptic loop:

Answer 21

1) Entorhinal cortex axons input to Dentate gyrus(DG)
2) Mossy fibres extend from DG to input on CA3
3) Schaffer Collateral fibres extend from CA3 and input to CA1

Question 22

Why is the trisynaptic loop useful for recording learning?

Answer 22

Simple architecture.

Question 23

What can be recorded in the trisynaptic loop?

Answer 23

Entorhinal cortex axon simulation and recording DG

Mossy fibre stimulation and CA3 recording

Schaffer collateral stimulation and CA1 recording.