Michael M. Merzenich

Neural Ontogeny of Higher Brain Function: Implications of Some Recent Neurophysiological Findings

Despite substantial experimental interest in the processes of “development” of the nervous system, there is surprisingly little direct understanding of neurophysiological processes underlying cognition and its ontogeny. There are several obvious reasons for this lack of progress. First, neuroscience has largely dealt with the issues of development in the terms of prenatal or early postnatal maturation of anatomical structures and connections, and of the origins of response primitives principally within “primary” cortical fields as they relate to anatomical maturation. Second, studies in animals beyond the first weeks of life have largely focused on examination of static anatomical and functional properties of sensory and motor systems. There has been very little study of the young or adult mammalian forebrain through a period of acquisition of new behaviors. Third, examination of complexly coupled flesh and blood neuronal networks, in which dynamic processes underlying progressive development of new perceptual abilities and motoric skills are resident, has been very limited. The dynamics of the complexly interconnected forebrain machinery cannot be reconstructed from data generated by the predominant neurophysiological method, i.e., by recording the activity of usually-unidentified network elements one at a time (see Mountcastle, this volume).