The Human Brain During the Second Trimester

The brain in the second trimester, the subject of Volume 3, is nearing anatomical maturity throughout the brainstem. In contrast, the neurogenesis and neuronal migration are still in progress in the cerebral cortex and cerebellum. Consequently, the authors chose to focus on the migration, sojourning, and settling of the neuronal populations belonging to these immature structures. These observations can help researchers develop a better understanding of normal brain development at this formative stage. In this volume, the authors offer consideration of a new concept regarding human cortical development: the identification of the stratified transitional field (STF), which continues to play an important role in later stages.