How far do most postsynaptic potentials travel before they die out.
A) to the axon hillock
B) to the terminal buttons
C) no more than a couple of millimeters
D) no more than 50 millimeters
E) both B and D

Question

Quizplus · Accepted Answer

Postsynaptic potentials (whether excitatory or inhibitory) are graded signals that decrease in strength as they travel along the dendrites of a neuron. Thus, they typically die out within a couple of millimeters of their origin. Option A is incorrect because the axon hillock (located at the base of the neuron's soma) is too far away from most dendrites to receive PSPs directly. Option B and E are incorrect because PSPs do not reach the terminal buttons; rather, they affect the dendrites and soma of the postsynaptic neuron. Option D is too far, as PSPs usually do not travel more than a few millimeters along dendrites.

How Far Do Most Postsynaptic Potentials Travel Before They Die