Synapses and Plasticity Two Flashcards
What is the term that describes measuring synapse activity?
Electrophsyiology
What does Electrophsyiology measure?
Either:
An AP
or
The current going through a receptor channel
What are the two types of recording?
Extracellular recordings (Population recordings or Field Recordings)
and
Whole cell recordings / Patch clamping
How is a Extracellular recording done?
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.
What are some advantages and disadvantages of field recordings?
Advantage: Its simple
Disadvantage:
- General info for a large population of synapses
- Not specific
What does FEPSP stand for?
Field Excitatory Post Synaptic Potential
When a FEPSP is measured in a voltage potential graph, how is an influx of ions shown?
As a downwards dip. As AMPA activation results in loss of positive ions from the external environments potential
What is a field recording useful for?
Evaluating normal baseline synaptic transmission potential
Describe how patch clamping works
Stimulating electrode is placed on a neurons axon, while the recording electrode is placed within the post synaptic neuron.
What does EPSC stand for?
Excitatory post synaptic current
What sort of receptor is responsible for Excitatory post synaptic current?
AMPA
Describe the appearance of a membrane potential recording for patch clamping, when theres a current inflow.,
It will always be negative from the baseline potential, regardless of ion charge.
What can patch clamping measure?
AP of a cell
Ion Channel Currents
Measure synapse function in individual neurons
What is highly unique feature of the brain?
Its plasticity - with regards to neurons
What is the definition of synapse plasticity?
The ability of synapses to change their strength in response to specific stimulation
In what way do synapses change their strength?
They become stronger of weaker from the basal strength.
What is synaptic strength?
Amplitude of current generated in a synapse
In what region of the brain is an excellent model for measuring synaptic plasticity?
Synaptic plasticity is normally measured in the hippocampus is thought to be the site of declarative (Explicit) memory.
What is explicit memory?
Faces, Numbers, facts
What is the advantage of using hippocampus slice preparations for measuring synaptic plasticity?
Stay alive for many hours
Relatively Simple architecture
Describe the trisynaptic loop:
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
Why is the trisynaptic loop useful for recording learning?
Simple architecture.
What can be recorded in the trisynaptic loop?
Entorhinal cortex axon simulation and recording DG
Mossy fibre stimulation and CA3 recording
Schaffer collateral stimulation and CA1 recording.
