At one postsynaptic neuron, the total EPSP change from RMP is +45mV and the total IPSP change from RMP is -15mV. Will an action potential be triggered? Assume RMP equals -70mV and threshold is -55mV.
yes or no
Yes.
To determine whether an action potential will be triggered, we need to consider the sum of the excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP) changes from the resting membrane potential (RMP).
In this case, the EPSP change is +45mV (depolarizing effect) and the IPSP change is -15mV (hyperpolarizing effect). To find the total change, we add these two values together:
Total change = EPSP change + IPSP change
Total change = +45mV + (-15mV)
Total change = +30mV
The threshold for triggering an action potential is -55mV. Since the total change of +30mV does not reach the threshold of -55mV, an action potential will not be triggered.
So, the answer is no.
Yes, an action potential will be triggered.
The total Excitatory Postsynaptic Potential (EPSP) change from the resting membrane potential (RMP) is +45mV, and the total Inhibitory Postsynaptic Potential (IPSP) change from the RMP is -15mV.
To determine if an action potential will be triggered, we need to consider if the membrane potential will reach the threshold for firing an action potential, which in this case is -55mV.
Given that the membrane potential starts at -70mV, the net effect of the EPSP and IPSP changes is +45mV - (-15mV) = +45mV + 15mV = +60mV.
Since the net effect is a depolarization of +60mV, which is above the threshold of -55mV, an action potential will be triggered.