A postsynaptic neuron has an RMP of -70mV and a typical threshold of -55mV. It has three presynaptic inputs-from neurons X,Y,and Z.Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously,the postsynaptic neuron depolarizes by 1 mV. If X fires 10 times and Y fires 10 times the result will be
A)a subthreshold summation.
B)presynaptic inhibition.
C)threshold is reached and an AP is fired.
D)many APs are fired.
E)the membrane depolarizes.

Question

A postsynaptic neuron has an RMP of -70mV and a typical threshold of -55mV.  It has three presynaptic inputs-from neurons X,Y,and Z.Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously,the postsynaptic neuron depolarizes by 1 mV. If X fires 10 times and Y fires 10 times the result will be
A)a subthreshold summation.
B)presynaptic inhibition.
C)threshold is reached and an AP is fired.
D)many APs are fired.
E)the membrane depolarizes.

Quizplus · Accepted Answer

The combined depolarization from X and Y firing 10 times each would be 10 mV (0.5 mV per stimulation), which is still below the threshold of -55 mV, resulting in a subthreshold summation.

A Postsynaptic Neuron Has an RMP of -70mV and a Typical