Genetic determinants of neuronal migration in the cerebral cortex

The techniques and concepts of modern molecular biology and experimental neurobiology give new insights into molecular mechanisms involved in neuronal migration within the cerebral cortex. The findings collectively indicate that a diverse family of genes and transcription factors co-operate in orchestrating the multistage, interrelated phenomena that include control of mode of cell proliferation, fate determination, establishment of polarity, detachment from the local substrate and migration to the proper laminar and a real position in the cortex. Herein, we will review some new data from our laboratory on the initiation of migration, nuclear translocation and attainment of final positions. We can now propose working models of the sequence of gene expression, cascade of multiple molecular pathways and cell-cell interactions that are involved in neuronal migration. Disruption or even slowing down of any step in neuronal migration during embryonic development can result in either gross or subtle abnormalities in neuronal positioning that may only later, during postnatal life, affect the formation of synaptic circuits and eventually behaviour.