Spatial summation occurs in a postsynaptic neuron
A) when several EPSPs from a single presynaptic input sum to reach threshold.
B) when EPSPs from several presynaptic inputs sum to reach threshold.
C) upon simultaneous interaction of an EPSP and an IPSP.
D) when several IPSPs from a single presynaptic input sum to hyperpolarize the membrane.
E) none of these answers.

Question

Quizplus · Accepted Answer

Spatial summation refers to the summing of multiple EPSPs from different presynaptic inputs to reach the threshold for firing an action potential in the postsynaptic neuron. This differs from temporal summation, which refers to the summing of EPSPs from the same presynaptic input over time to reach threshold. Option A refers to temporal summation, while options C and D refer to inhibitory effects that would not lead to firing an action potential. Option E is incorrect as one of the options is correct.

Spatial Summation Occurs in a Postsynaptic Neuron