Insult during neuronal migration results in delayed neuroneal migration and organization, which results in ceain disorders. The least likely possibility is:
Formation & maturation of brain neocoex involve neuronal proliferation, differentiation & migration. With their expansion, germinal matrix forms at 7 weeks gestational age d/t subependymal neuronal proliferation, lines the lateral & third ventricles and involutes at 28 to 30 weeks With the exception of outer layer, neurons migrate from germinal matrix to coex in an inside out sequence: i.e. those that will form the deepest coical layer (6) migrate first, followed by layers 5, 4, 3 and finally layer 2 (layer 1 will not migrate). This neuronal migration & layering process occurs from weeks 6 to 7 through 24 to 26, when full 6 layered coex is achieved. So a brain insult during neuronal migration can result in abnormalities ranging from lissencephaly (smooth brain), to schizencephaly (split brain), polymicrogyria, and laminar or focal heterotopiasQ.
Polymicrogyria
Schizencephaly
Lissencephaly
Focal coical dysplasia without ballon cells.