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Neurobiology Exam 1: Post-synaptic Potentials

Terms in this set (11)

Graded in size. (different from AP, vs. all-or-nothing)
-Cellular mechanism: activated not by voltage gates but by ligand-gated channels (ligand is neurotransmitter (NT)).
-Important b/c: different amounts of NT in synapse can trigger different rates of APs. This way, neurons can regulate frequency.

Transient (same as AP)
-Cellular mechanism: The rapid influx of ions and subsequent closing/inactivation of channels due to voltage changes.
-Important b/c: The action potential is significant because it constitutes a dramatic change in membrane potential. This can only be accomplished this way in a short time.

No refractory period (different from AP, vs. refractory period)
-The action potential needs a refractory period to keep the action potential traveling in one direction. But the synaptic potentials spread out so they can sum up and depolarize the cell enough to start the action potential at the axon hillock.

Depolarizing & polarizing (different from AP, vs. just depolarizing)
-Cellular mechanism: excitatory NTs (e.g., glutamate, etc.) can cause excitatory PSPs (EPSPs) and inhibitory NTs (e.g., GABA, etc.) can cause inhibitory PSPs (IPSPs)
-Important b/c: Inhibition can reduce signals sent by a certain neuron, so that we can prevent a neural impulse from firing, and excitation can cause a neural impulse to fire when needed.
In short, it gives the cell more versatility in how frequently APs are generated.

No threshold (different from APs, vs. threshold)
-Because potentials are graded, there is no threshold. The only threshold happens in the axon. The probability of an action potential firing is mainly dependent on the type and amount of NT received by the cell.