TRANSIENT CIRCUITS IN THE DEVELOPING BRAIN

During early mammalian brain development, transient neurons and circuits form the scaffold for the development of neuronal networks. In the immature cerebral cortex, subplate neurons in the lower cortical layer and Cajal-Retzius cells in the marginal zone lay the foundations for cortical organization in horizontal layers and translaminar radial circuits (“cortical columns”). Patterns of spontaneous activity during early development synchronize local and large-scale cortical networks, which form the functional template for generation of cortical architecture and guide establishment of global thalamocortical and intracortical networks. These networks become established in an autonomous fashion before the arrival of signals from the sensory periphery and before the maturation of cortical circuits. The subplate, which is a transient structure located below the developing cortical plate, orchestrates alignment of these autonomously established pathways by integrating spontaneous and sensory-driven activity patterns during critical stages of early development. DOI: 10.1126/science.abb2153