Question

What will happen if you inject depolarizing current into an axon midway between the soma (cell body) and the axon terminals? Assume that the current causes an action potential to occur at the injection site and that the axon was quiescent (not spiking) prior to the current injection.

An action potential will travel towards the cell body.

An action potential will travel towards the axon terminals.

One action potential will travel towards the cell body, and another action potential will travel towards the axon terminals.

Answer 1

When injecting depolarizing current into an axon midway between the soma and the axon terminals, an action potential will be generated at the injection site and it will travel towards the axon terminals.

Step-by-step explanation:

When injecting depolarizing current into an axon midway between the soma and the axon terminals, an action potential will be generated at the injection site. The depolarization from the action potential will spread in both directions along the axon, but since voltage-gated Na+ channels inactivate at the peak of the depolarization, the depolarization cannot propagate back towards previously opened channels. Therefore, the action potential will only travel towards the axon terminals and not towards the cell body.