If an action potential lasts from the beginning of the rising phase to the point

Hi Max,

Not sure about the answer to this, but found something that will shed light (source provided below):

Given that the frequency of action potentials is determined by the strength of the stimulus, a plausible question to ask is what is the frequency of action potentials in neurons? Another way of asking this question is how many action potentials can a neuron generate per unit time (e.g., action potentials per second)? Physiologically, action potential frequencies of up to 200-300 per second (Hz) are routinely observed. Higher frequencies are also observed, but the maximum frequency is ultimately limited by the absolute refractory period. Because the absolute refractory period is ~1 ms, there is a limit to the highest frequency at which neurons can respond to strong stimuli. That is to say that the absolute refractory period limits the maximum number of action potentials generated per unit time by the axon. As described previously, the strength of the stimulus must be very high in oder to ensure that the duration of the action potential is as short as the duration of the absolute refractory period. A stronger than normal stimulus is required to overcome the relative refracctory period.

Because the absolute refractory period can last between 1-2 ms, the maximum frequency response is 500-1000 s−1 (Hz). A sample calculation is shown below with the assumption that the absolute refractory period is 1 ms in duration.