Epigenesis, Synapse Selection, Cultural Imprints, and Human Brain Development: From Molecules to Cognition
The human brain is neither John Locke’s “blank slate” deprived of any pre-existing innate structure – or, in a modern AI language, a random network of undifferentiated neurons fully instructed by experience – nor a fully genetically determined, irrevocably hard-wired neuronal architecture. Neither is it represented by the simplistic yet very popular deep-learning artificial networks. The 85–100 billion neurons of the human brain and their synaptic connections, that arose over million years of evolution and for each individual brain over almost 15 years of postnatal development, possess an original organization unmatched by any of our current computers. It is a unique compromise between an eminently variable, intrinsically rich connectivity and a set of species-specific, genetically determined, rules, which unambiguously make our brain that of Homo sapiens.