Only a matter of time: developmental heterochronicity captures properties of the human connectome

Brisbane Convention & Exhibition Centre 

Brain network organization is constrained by a trade-off between the energetic cost of forming connections and the advantages they confer on network function[1]. Computational models have shown this cost-benefit trade-off can explain many-but not all-network properties[2,3]. During gestation, brain development proceeds according to a precise spatiotemporal pattern defined by a series of morphogen gradients[4]. Cortical areas display heterochronicity, differential timing of key developmental events, which induces spatial patterns that persist in later life as smoothly varying gradients in cytoarchitecture, neuronal connectivity, and functional activation[5]. Therefore, heterochronicity may provide an additional constraint on the formation of cortical connectivity[6,7]. While the putative role of developmental timing on cortical wiring has been modelled abstractly[8,9], prior studies have not accounted for the brain's geometry, a critical factor in modeling the potential role of diffusing molecular gradients. To address this, we developed a framework to examine how heterochronicity and synchronicity across cortical areas can shape human brain networks.