Synaptic Epigenesis and the Social Brain

This chapter presents “synaptic epigenesis,” as the foundation for understanding cultural memory in neuroscientific terms. It is a term Changeux coined to describe modulations of gene expression and transgenerational effects triggered by the brain’s interactions with its social, physical, and cultural environment. It has a broader meaning than the concept of DNA “epigenetics” subsequently used in molecular biology to refer to unrelated mechanisms of DNA covalent modifications such as methylation or chromatin remodeling. We suggest that synaptic epigenesis ensures ongoing interactivity between the brain’s gene-guided functions and input from particular biocultural environments. This interaction may contribute to the development and specification of individuals’ distinctive brain synaptic networks through a process of selection based on the stabilization of strong synapses and the elimination of weak ones not activated by enveloping environments. Moreover, continuous interactivity instantiates and influences not only neuronal networks unique to individuals, but also prevalent patterns and characteristics of socially, culturally primed, consolidated, or modified interconnectivity. Such neural plasticity affects the kinds of memories that immediate experience and mediated collective forms of identity are likely to valorize, highlight, marginalize, or delegitimize. This epigenetic Darwinian process of cultural memory validates some longstanding concepts that emerged in French sociology from Maurice Halbwachs to Pierre Bourdieu. In addition, examples embedded in selected literary works by Nabokov, Faulkner, and Edmund Gosse illustrate this neuroscientific theory, vividly showing how extracerebral cultural memories are preserved in literary artifacts.