The resting membrane potential of neuron Ais-70 and threshold is -60 mV. Multiple neurons synapse on neuron A: some are excitatory and others are inhibitory. Assume that each presynaptic neuron that is stimulated produces a 5 change in potential on the postsynaptic membrane If 3 inhibitory presynaptic neurons are stimulated and produce IPSPS on neuron A, how many excitatory neurons must simultaneously be stimulated to generate an action potential in neuron A (assume that spatial summation occurs)?
a. 3
b. 5
c. 1
d. 4
e. 2