Action potential

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yjj8817

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Does increase in stimulus intensity lead to higher frequency of action potential? If yes, Why does this occur?

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i think this may depend on context, but assuming your talking about the somatic sensory system, then yes stimulus intensity is encoded in the frequency of action potentials relaying up into the brain. for example, louder sounds (i.e. larger wave amplitude) are perceived as louder because the sensory neurons at the inner ear fire at a faster rate. when you touch something softly, the sensory neurons in the skin fire at a lower frequency.

as for why, I think the key thing to know is that if the stimulus is very large, then the neuron's dendrite will undergo a very large depolarization. if the depolarization is larger, then the membrane potential of the neuron will be higher than the threshold potential for the action potential for a longer period of time. if the membrane potential is higher than the threshold potential for longer, then the action potential frequency will increase.
 
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