Impulse traveling in a smaller unmyelinated axon

This movie shows that the action potential (AP) in the squid axon propagates much more slowly when the axon's diameter is reduced ten-fold (from 500 um to 50 um). Compare these graphs with those of the previous movie: Over the same 10,000 um length of axon (now 200 rather than 20 times its diameter), the spatial voltage profile shows a clear waveform reminiscent of a temporal AP. The voltage-vs-time plots at the 4 electrodes confirm that the AP travels much more slowly along this smaller-diameter axon.