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As well known brain are connected to our body by neuronal cells. it transmits and receives its data by action potential during neuronal cells. i wonder if any one can explain to me the properties of this current. can we consider this current as an AC current?

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  • $\begingroup$ No. This question is too broad - there are many resources for you to read up on the basics of action potentials. $\endgroup$ – Bryan Krause Aug 4 '17 at 17:58
  • $\begingroup$ Indeed, an action potential really isn't a current at all, at least as an electrical engineer would understand current. Rather, it's a wave of cell membrane depolarization. $\endgroup$ – jamesqf Aug 4 '17 at 19:21
  • $\begingroup$ @jamesqf an action potential is indeed no current, it is a voltage difference that changes over time. The action current is definitely a current, namely a net flow of charged ions through the cell membrane. $\endgroup$ – AliceD Aug 5 '17 at 14:06
  • $\begingroup$ @AliceD: Yes, but that ion flow current is perpendicular to the axon, whereas the action potential propagates along its length. It's also pretty fundamental to the nerve's (normal) operation that an AP propagates one way. Changing it to an A/C current would mean redesigning everything from scratch :-) $\endgroup$ – jamesqf Aug 5 '17 at 18:58
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You know those analogies of the brain being a computer and nerves being wires leading to and from it?

Those analogies are LIES.

There are no wires in the nervous system. Each neuron is a capacitor, the sodium potassium pumps create an electric charge in each neuron, and the neuron keeps that charge until the neighboring neuron (let's pretend it's not a sensory neuron) gives it a signal, in the form of an electric jolt or neurotransmitters.

That causes the neuron to equal out the charges on the inside and outside, called depolarization. Watch this video: action potential crash course A nerve could contain a bunch of neurons in a line next to each other, with one depolarizing the other.

This functions like a wire, in the way that it can transmit signals, but should be though of more like a domino effect, where the dominoes can stand themselves back up after the depolarization.

Electrons do not move from one end of the nerve to the other, only the "wave" of neural depolarization.

And since each neuron operates like a capacitor, it would be DC not AC current.

When I first learned about neurons, I was flabbergasted that it worked this way. I thought it was like wires, with a positive and negative end...

It couldn't be more different...

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  • $\begingroup$ There are a few inaccuracies here. "Those analogies are LIES." - No, they are analogies. "Each neuron is a capacitor" - neurons have capacitive elements, but that doesn't make them 'capacitors.' "the sodium potassium pumps create an electric charge in each neuron" - only sort of. The Na/K pump establishes ion concentration gradients. The resting potential comes from differential permeabilities in the presence of those gradients. "Electrons do not move from one end of the nerve to the other, only the "wave" of neural depolarization." - Electrons don't move to the end of a wire either. $\endgroup$ – Bryan Krause Aug 14 '17 at 20:07
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    $\begingroup$ "A nerve could contain a bunch of neurons in a line next to each other, with one depolarizing the other." - Nerves are bundles of axons. You don't have sequences of cells in a line in nerves, just a parallel bundle of fibers. "And since each neuron operates like a capacitor, it would be DC not AC current." - Besides the problem that neurons aren't really capacitors, capacitors can be present in both AC and DC circuits, they just behave differently. $\endgroup$ – Bryan Krause Aug 14 '17 at 20:15
  • $\begingroup$ @BryanKrause electrons DO move to the end of the wire $\endgroup$ – 4D Neuron Sep 4 '17 at 19:34
  • $\begingroup$ Not really. On net they do, but you won't find an electron from one end ending up on the other end. The same is true of ions in a neuron. $\endgroup$ – Bryan Krause Sep 4 '17 at 23:30
  • $\begingroup$ dc, not ac current. $\endgroup$ – 4D Neuron Sep 5 '17 at 3:27

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