Bear in mind that nerves do not operate like electrical wiring. There is no flow of electrons in nerves; they operate by the propagation of a wave of membrane depolarization. (The membranes of ~all cells , and especially neurons, are polarized in that there is a gradient of charge across the membrane; cells are generally net negatively charged inside, with their environment having a net positive charge. Neurons use voltage-gated ion channels, channels which open or close depending on the strength of the charge gradient, to create a self-propagating wave of depolarization; ions move across the membrane, reducing the charge gradient, causing neighbouring ion channels to open and ions to flow in there as well. This results in a signal that rapidly propagates along the neuron.)
As a result, a rune that reduces conductivity (in whatever sealing-magic way might let it do that without breaking all of chemistry) may well not affect nerve impulses.
You are entirely correct that the nervous system is not a collection of wires in its precise functionality. Thank you for the reminder. I had honestly not recalled all that until then.
However, Itachi still instantly dies:
(1) The evolution of the myelin sheathing specifically was a breakthrough in that it increased neural system performance drastically in organisms via insulating the axons. That alone strongly suggests that conductivity and insulation are vital for neurons to function. In addition, that single example shows that even
increasing conductivity significantly would similarly disable nerves. This is significant because we can observe a small part of it IRL. So that's a new avenue (incidentally supporting the importance of conductivity and insulation in the nervous system), which is nice, but let's go back to the original:
(2) A
precise example of what removing electrical conductivity would do:
Mitochondria produce ATP through oxidative phosphorylation, which relies on electron transport chains where electrons are transferred through a series of protein complexes. This no longer works, since those electrons cannot be transferred. Thus Itachi's cells no longer produce ATP. No ATP means no active transport of ions (The Na+/K+ ATPase pump uses vast and continuous ATP to maintain the gradient of sodium and potassium ions across the cell membrane), disrupting resting membrane potential and action potential generation in all nerves. The moment that happens, Itachi's nerves stop working.
Itachi still becomes an S-Class vegetable.
(3) As a third option, I do not think that the voltage-gated channels would actually open (ignoring the ATP path above) without the voltage gradient changes on the membrane being conducted to the channel. In other terms that gate should not "know" anything about the charge gradient because conductivity is the only way it *can* know (via the voltage sensor regions - either directly or though an electrical field, both of which require electrons to be conducted). Effective removal of physical properties makes things confusing, but here we are. Specifically, without electron movement we should not observe the voltage sensor regions detecting anything, hence all channels remaining closed. Anyway in this case, the same thing happens: Nerves don't work and the bird is dead.
To make a long story short, the nervous system makes use of electrical conductivity on multiple steps of its complicated and interconnected Rube Goldberg machine. If we take away any part of that, the machine no longer works. The above are some examples of specific parts that are being 'taken away', with explanations as to why they'd stop the machine immediately. These are certainly not exhaustive, but sufficient to demonstrate previously claimed capabilities.
I am therefore confident that
we can simplify all of this to: "The effective removal of electrical conductivity is incredibly and immediately lethal."
Thank you for coming to my TED Talk.
(As I am not a professional in this field, this is half-remembered book knowledge combined with wikipedia patches. I hope that this longer explanation passes muster, and at least one of the (much higher/much lower) conductivity runes make sense with respect to their intended function.)
Edit: Also, none of the in-depth discussion really matters to Hazo, since he will expect and observe the "bundle of wires" concept in action. The simplified version is sufficient for his purposes.
