Can cognitive functioning of the human brain change the physical state of the brain? E.g. does self-awareness, self-reflection change the number of neurons or synapses among neurons? I.e. I am trying to develop self-modifying neural networks as described in my other question https://ai.stackexchange.com/questions/7966/dynamic-self-improving-self-modifying-neural-networks-which-can-simulate-goede and I am interested in the biological process that can be analogues of self-modifying neural networks. What determines the physical structure of the brain - number of neurons and synapses and are the cognitive functions among the determinants? I guess that generally the brains can be less developed matter comparing to the artificial neural networks that humans can invent or that can self-evolve in silica after sufficient period of time and that is why human brain can be more restricted in its self-improving capabilities than in silica ANNetworks. Similar situation is with genetic algorithms which can allow unrestricted number of sexes while biology has at most two sexes.