Neurophysiology Module 3

Action Potentials

Some Neurons Are Weird

Although the action potentials of most neurons resemble those described above, some neurons have action potentials with different properties.

As an example, cerebellar Purkinje cells produce complex spikes, which are very broad and complicated action potentials.

As shown to the left, the complex spike has a duration of almost 10 msec. A complex spike is characterized by an initial prolonged large-amplitude spike, followed by a high-frequency burst of smaller-amplitude action potentials. The duration of complex spikes is due to the presence of P-type voltage-gated calcium channels, whose opening contributes to the generation of the action potential.

In general, voltage-gated calcium channels open and close slowly, resulting in a prolonged movement of ions. This generates a long-duration action potential.


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