Mechanical morphogenesis and the development of neocortical organisation

The development and evolution of complex neocortical organisations is thought to result from the interaction of genetic and activity-dependent processes. Here we propose that a third type of process – mechanical morphogenesis – may also play an important role. We review recent theoretical and experimental results in non-linear physics showing how homogeneous growth can produce a rich variety of forms, in particular neocortical folding. The mechanical instabilities that produce these forms also induce heterogeneous patterns of stress at the scale of the organ. We review the evidence showing how these stresses can influence cell proliferation, migration and apoptosis, cell differentiation and shape, migration and axonal guidance, and could thus be able to influence regional neocortical identity and connectivity.