First, the output neuron on the left receives excitatory signals from two neurons on the right, generating an action potential. Then the third neuron on the right fires. This time, the output neuron on the left does not generate an action potential, and so no feelings of anxiety leave the amygdala. That's because the third neuron produced an inhibitory postsynaptic potential. Let's follow the action potential down the axon and find out how the GABA receptor works to produce this inhibition.