Neural plasticity, heterochrony, and the onto-phylogeny of consciousness.

From a biological standpoint, the consciousness of a living organism equipped with a complex nervous system may be considered the result of the complex structure and functioning of its brain. Subsequently, the neurobiological bases of consciousness should be traced back to the systemic nature of the macroscale neural circuitries of the brain, which are, in turn, the basic outcomes of certain fundamental microscale neuronal processes whose spatiotemporal action gives rise to a much more complex systemic process called neural plasticity. It is closely related to brain evolution from both phylogenetic and ontogenetic perspectives. It is the primary neurobiological process that links the brain with internal and external environments and the related experiences. Since consciousness is a theoretical construct introduced mainly to account for the (ontogenetically evolving) integrative subject-object intermediation, it might be possible hypothesize the existence of a relationship between consciousness and neural plasticity, at least from a biological standpoint. In these terms, the phylogenetic development of human consciousness, when human lineage started after the split from that of nonhuman primates, might be partially inferred by comparing the (ontogenetic) development of human and nonhuman primate brains, using an extended meaning of the concept of neural plasticity as the main neurobiological process of reference. What seems to emerge from this comparison is the evolutionary occurrence, during anthropogenesis, of distinguishing (transcriptional) heterochronic phenomena concerning neurodevelopmental processes.