A crucial feature of the brain is the complex process of its development that sustains its highly sophisticated plasticity and adaptive cognitive skills. In the mammalian neocortex embryogenesis, different types of projections neurons are generated from an initial population of neural progenitors and organize into six structured layers through differential migration and self-sorting. We examine how this spatio-temporal pattern can be regarded as an emergent dynamic, considering cells as behavioural units, and cell-cell communication as plastic interactions. In collaboration with A. Davy (CBD), we particularly focus on the role of Eph/Ephrin signalling pathway that mediates cell/cell interactions, especially differential adhesion / repulsion. In a joint effort with R. Fournier & S. Blanco (Laplace), we target a full quantitative account of the spatio-temporal dynamics of this non-linear system, with a model integrating the three levels: molecular cascades, behavioural cell-cell interactions and large-scale patterns.