As far as I understood, they are talking about a certain homeostatic state of the brain which is optimal for the right amount of signal transmission between neu

As far as I understood, they are talking about a certain homeostatic state of the brain which is optimal for the right amount of signal transmission between neurons. If a set of neurons are on the critical point, they neither fizzle out the signal nor amplify it. I think this is somewhat related to criticality in nuclear fission in nuclear reactors - if a reactor is sub-critical, then any reaction fizzles out; if it is super-critical, then the reaction is exponential. If the reactor is close to the critical point, then the reaction is sustained at a relatively constant rate. The brain probably couldn't function very well if their neurons were generally super-critical and all fire very quickly if one fires. And the brain probably wouldn't function well if the neurons were all sub-critical, and any attempt at transmitting a signal would die out. The researchers studying this critical point theory for the brain also seem to be seeing parallels in brain activity and other critical systems. Particularly, that a system at a critical point can be easily tipped over the critical point with a small input or simply a change in one of its components. And that some systems in nature seem to use this to stay organised. The hypothesis is very cool and seems to be sensible, but the article and video depart a bit too much into adjacent topics to offer a good introduction to the subject. For example, I couldn't find the relevance of the critical point between random and organised systems in metal atoms. The example of seeing predators in nature was also a bit contrived although it illustrates how a small change in a large neural net can produce large meaningful organisation in the activation of neurons. It feels very intuitive that a brain needs to operate at this perfect balance between super-criticality and sub-criticality, I can understand why some scientists feel so strongly about it. I would welcome corrections if I did not understand something as intended.