In anatomy, the germinal matrix is a highly cellular and highly vascularized region in the brain out from which cells migrate during brain development. The germinal matrix is the source of both neurons and glial cells and is most active between 8 and 28 weeks gestation. It is a fragile portion of the brain that may be damaged leading to a germinal matrix hemorrhage (grade 1 intraventricular hemorrhage). Location/anatomy: The germinal matrix is next to the lateral ventricles (the "inside" of the brain).