This article proposes that behavioural advancement during mammalian evolution had been in part mediated through extension of total developmental time. Such time extensions would have resulted in increased numbers of neuronal precursor cells, hence larger brains and a disproportionate increase in the neocortex. Larger neocortical areas enabled new connections to be formed during development and hence expansion of existing behavioural circuits.
This article, based more on speculation than on clinical work, aims at clarifying the nature of child autistic syndromes using two elements: epigenetic findings concerning the construction of human brain and the idea that there is a self-organizing development and functioning of the living. First initiated by H. Atlan (1979) and A. Bourguignon (1981), this approach could lead to a fruitful understanding of autistic disturbances, both consistent with developmental neurobiology and psychodynamics.
This paper argues that there is a revolution afoot in the developmental science of gene-environment interplay. We summarize, for an audience of developmental researchers and clinicians, how epigenetic processes - chromatin structural modifications that regulate gene expression without changing DNA sequences - may offer a strong, parsimonious account for the convergence of genetic and contextual variation in the genesis of adaptive and maladaptive development.