Intrinsic firing properties and synaptic scaling

Question 1

3 basic types of cell (intrinsic firing)

Answer 1

• regular spiking
• fast spiking
• intrinsically bursting

Question 2

Geiger (1995)

Answer 2

FS-PV interneurons express AMPA receptors with high caclium permeability and fast gating due to low GluA2 mRNA

Question 3

Functional implication of low GluA2 mRNA in FS-PV interneurons

Answer 3

Fast EPSP time course, coincidence detection.

Question 4

Du (1996)

Answer 4

Kv3 K+ channel subunits are selectively expressed in PV+ cells - molecular mechanism underlying phenotype.

Question 5

Functional implication of Kv3 subunit expression in PV+ interneurons?

Answer 5

drives fast repolarisation therefore fast spiking

Question 6

What role do FS-PV interneurons play in the hippocampus?

Answer 6

Feedforward inhibition

Question 7

Turrigiano (1994)

Answer 7

STG neurons in lobster isolated, no longer fire in bursts, after 3-4 days regained burst firing. Due to changes in intrinsic conductance - increase calcium and decrease outward.

Question 8

Turrigiano (1998)

Answer 8

Cultured neocortical neurons. Chronic blockade of cortical culture activity increased amplitude of EPSCs without changing kinetics. Blocking GABA initially raised firing rates, but over 48-hour period, mEPSC amplitudes decreased and firing rates returned close to control values.

Question 9

3 points to synaptic scaling

Answer 9

• Ensure firing rates do not saturate in development
• Stabilise synaptic strengths during hebbian modification
• Facilitate competition in synapses.

Question 10

Gainey (2009)

Answer 10

Differential mechanisms of AMPAR recruitment in synaptic scaling and LTP. SS blocked by GluR2 shRNA knockdown, not GluR1 - LTP. Chimeric GluR2 could not rescue.