>>13320750That's honestly a pretty sweet deal. You lose more than a neuron every day just due to being mortal, so if the devil is taking one neuron a day, that's a tremendous improvement. Unless he's taking one extra, and then it's not a big addition, unless he's sharking around to remove lynchpin neurons that will render you tardled in a couple decades.
Even so, all it takes for you to make this immortality is to survive until we get better neurogenesis agents, which we're honestly quite close to. Since neurons grow to interact with each other, you can dump a bunch of totipoten stem cells into a petri dish and get a neural network. Plus we've already got some decent enneurogens (lion's mane, etc) already. If you could just make it a few decades this becomes an amazing bargain.