>>11421611It won't take long for it to die. The brain operates under a 'use it or lose it' principle. For people who have lost the sensory organs in one modality, that part of the cortex is reconfigured to serve another purpose, e.g. blind people show responsiveness in the visual cortex to sound*, and if you lose a finger, that part of the motor cortex is taken over to control adjacent fingers**.
*
https://www.sciencedirect.com/science/article/abs/pii/0304394094111356**
https://link.springer.com/article/10.1007/s002210000456If all input is removed, spontaneous activity alone won't keep it alive for very long. We see this in in-vitro experiments too, where a (slice of) the brain is kept alive in a dish to more easily record activity from individual neurons. But these slices last for max a few hours to days, and then atrophy. So in other words, you probably can't keep it alive with 0 chemical/electrical interactions from the outside world. In order for it to stay alive for longer, you'd need to give it input.
In the period where it does stay alive, its activity will be driven by its endogenous properties. That is, spontaneous cortically generated activity (which is pretty much dominant in the normal state too) will be the only driver of activity.
