When several IPSPs arrive at the axon hillock rapidly in sequence from a single dendritic location, hyperpolarizing the postsynaptic cell more and more and thus preventing an action potential, this is an example of
A) temporal summation.
B) spatial summation.
C) tetanus.
D) the refractory state.
E) an action potential with an abnormally high peak of depolarization.

Question

Quizplus · Accepted Answer

This is an example of temporal summation, where several IPSPs arrive at the axon hillock in rapid succession from a single dendritic location, leading to the summation of their hyperpolarizing effects on the postsynaptic cell. This can prevent the generation of an action potential. Spatial summation, on the other hand, is the summation of IPSPs and EPSPs from different dendritic locations, which can also affect the generation of an action potential. Tetanus refers to a sustained contraction of skeletal muscles due to rapidly repeated stimulation. The refractory state is the period during and after an action potential when the neuron is unable to generate another action potential. An action potential with an abnormally high peak of depolarization is not related to this scenario.

When Several IPSPs Arrive at the Axon Hillock Rapidly in Sequence