Threshold can be defined as the minimum voltage needed to generate an action potential. is the threshold for the first action potential the same as, or different from, the threshold for the second action potential with a 60 msec interval?

The question is incomplete as it does not have the data which is provided.

The threshold for the first action potential will be lower compared to second action potential.

Explanation:

The action potential is generated in the cell because of the movement of the ions across the membrane of the neuron cell. The resting potential of the cell membrane is maintained between the -40 to -90 mV and the resting potential of the neuron membrane is at -70mV.

When depolarization occurs, the potential changes and when reaches the threshold generates an action potential.  In the given experiment we observed that the threshold potential of the first action potential is 20mV and second potential at 25 mV at 60 msec.

This shows that the action potential of the first action potential is lower than the second potential.

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