How much electrical energy is required for intracellular stimulation (firing) of a human neuron? Electrical energy is measured in joules, and equal to voltage multiplied by current. If you don't know energy, you may specify voltage applied and current. Just for example, to capture heart, a pacemaker must discharge 0.1 microjoule of electrical energy.

There might be more parameters involved like pulse width, phase etc. Energy combines all the parameters in one single value. In case you don't know energy level, please specify the defining parameters as well.


1 Answer 1


I think this question is somewhat ill-posed, but I'll try to answer it:


All you have to do is to short the inside of the cell to the outside/ground. Of course in reality this means expending some energy somewhere, but at that point it's an engineering problem, not one of biology, and it has nothing to do with the neuron itself.

Action potential firing is a completely passive process. The only part that requires energy (besides protein synthesis) is for the sodium-potassium ATPase that maintains sodium and potassium gradients.

  • $\begingroup$ I agree that this is an ill-posed question. (OP is probably trying to ask the engineering question...) Na/K-pump spends enormous amount of energy to ready that state though. Each AP does have an associated energy cost that way. $\endgroup$
    – Memming
    Oct 23, 2017 at 21:33
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    $\begingroup$ Yeah, that cost is necessarily driven by things like the size of the neuron, how branched the axons are, myelination, etc, and the cost is still a fraction compared to the cost of synaptic transmission in most cells: action potentials are really incredibly efficient. Synaptic transmission is really only costly because you have excitation and inhibition that cancel each other out in terms of voltages but create large currents that require pumping. All that said, I read the OP's post to be mostly about triggering, rather than propagating an AP. $\endgroup$
    – Bryan Krause
    Oct 23, 2017 at 22:55

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