During this state, the inner membrane surface becomes more positive than the outside:

A minimum amount of stimulus that can start an action membrane potential is called:

_____is the effect of triggering an action potential in a neuron from presynaptic neurons.

 Neurotransmitters located in the ____________ are signaling molecules that cross the synapse and bind to ____.

Which of the following does not happen during membrane depolarization? 

What causes an action potential to propagate in a specific direction along the axon?

 _____ is the extensively studied neurotransmitter associated with depression.