Spatial summation occurs on a postsynaptic neuron would occur when
A)several EPSPs from a single presynaptic input sum to reach threshold
B)EPSPs from several presynaptic inputs sum to reach threshold
C)there is simultaneous interaction of an EPSP and an IPSP
D)several IPSPs from a single presynaptic input sum to hyperpolarize the membrane
E)none of the above take place

Question

Quizplus · Accepted Answer

Spatial summation occurs when EPSPs from several different presynaptic inputs summate to reach the threshold of the postsynaptic neuron for firing an action potential. This is in contrast to temporal summation, where EPSPs from a single presynaptic input sum over time to reach threshold. Option A is incorrect, as summation of multiple EPSPs from a single input would be an example of temporal summation. Option C refers to simultaneous interaction of an EPSP and an IPSP, which would result in cancellation of the two potentials and inhibition of the postsynaptic neuron. Option D refers to temporal summation of IPSPs, leading to hyperpolarization of the membrane potential. Option E is clearly incorrect, as spatial summation is a well-established model for understanding neuronal signaling in the brain.

Spatial Summation Occurs on a Postsynaptic Neuron Would Occur When