Fissile material has a point of criticality beyond which nuclear fission amplifies explosively. This is call the critical mass. Which is the minimum quantity of fissile material in a given space that will sustain an ongoing nuclear fission.
Could there be something similar in neural networks concerning consciousness ? Our brains are made of 100 billion neurons and even more glial cells. Those living cells are made of ATOMS. Atoms are a "dead" nature. How can an object feel pain ?
So if we put 100 billion neurons together in a way which pain, pleasure and emotions can be felt. Is there a limit to add neurons ? Could we add neurons infinitely or would there be a point of criticality above which consciousness itself would develop and sustain other feelings and sensations and the body, the flesh and the brain would become facultative and could be discarded.
Nature only gave us 100 billion neurons ? Why ? What would happen if we had 200 billion, 300 billion ?? Is there a Critical point ??
There are a few questions here, let me unravel them from one another:
"How can an object feel pain?" - This is the question of consciousness, and there's not a particularly good answer to it. I'd recommend asking in Philosophy, rather than Physics, to try to get a detailed answer to that question. Also, I'd recommend doing quite a bit of reading.
"Is there a limit to add neurons?" "Nature only gave us 100 billion neurons. Why?" - The very short answer to this is that everything you add to an organism increases the amount of growing it needs to do, and the amount of energy it needs. We already have an incredibly long, incredibly helpless childhood. At some point, the reward for adding more neurons - which is presumably more memory, more pattern-matching ability, or something similar - became less beneficial to survival than the reward for becoming adult and self-sufficient sooner. At that point, there's no reason for the brain to get bigger - it's doing the best that it can.
"Is there a critical point??" - I'd have to say no. What you're asking about is the idea of a disembodied consciousness. If consciousness can exist without a body, then there's no reason to believe that adding more neurons will help. If consciousness requires a body, then there's no way to get beyond the body - more neurons might increase the capabilities of the brain, but not produce a sudden, critical change like the one you describe in nuclear fission.