Exp tech in Neuro; in vitro electrophysiology

Question 1

Types of electrical recording

Answer 1

Intracellular
Patch-clamp
Extracellular
Multiunit recording

Question 2

Intracellualr

Answer 2

Sharp microelectrodes

Question 3

Patch clamp

Answer 3

High resistance seal electrodes

Question 4

Extracellular

Answer 4

Low-resistance glass,carbon or metal electrodes

Question 5

Microelectrode uses

Answer 5

Detect neurotransmitters (voltametry)
Detect vesicular tissue (capacitance recordings)
Reveal structure of neurones by introducing morphomarkers
Introduce calcium indicators into neurones
Introduce drugs, mRNA, antibodies etc.
Harvesg cellular materials mRNA

Question 6

Experimental approaches to study the nervous system

Answer 6

Human subjects
Intact conscious animals
Anaesthetised animals
Acute brain preps - brain slices, perfused systems.
Cultured systems - organotupe slice cultures, dissociated neurones, expression systems.
Artifical membranes.
This list (top to bottom) has decreasing physiological relevance but increasing ease of experimental manipulation.

Question 7

Brain slice system advantages

Answer 7

Retains connectivity (especially local circuits)
Native tissue thus normal expression.
Can incorporate diverse brain regions.
Good for pharmacological/electrophysiological intervention.
Permits experiments that would be too difficult/unethical on whole organisms.
No confounding BP or HR effects.
No effects of anaesthesia.

Question 8

Brain slice systems disadvantages

Answer 8

Some damage caused during prep.
Difficult to patch.
Limited to a few hours recording.
Limitd thickness of tissue.
Cannot incorporate long axon tracts.
Ionic environment does not exactly mimic normal EC conditions.

Question 9

In vivo recording advantages

Answer 9

Intact structure/connections.
Can relate to behavious / other functions.
Can be maintained for long periods.
Can stimulate physiological pathways.
Can incorporate diverse brain regions.

Question 10

In vivo recording disadvantages

Answer 10

May require anaesthesia.
Unstable / short recordings.
May be confounding factors due to BP/HR effects.
Difficult to access tissue, very invasive.
Limited scope for pharmacological/electrophysiological intervention.
Ethical considerations.
Uncertainty of what one is recording.