Neuroplasticity and the developing brain: implications for therapy

Normal brain development consists of a series of interdependent and temporally overlapping processes. These include cell division, migration and aggregation, dendritic elaboration, axonal elongation and arborization, and synaptogenesis. There is a general pattern in all of these of predictable early development with evidence of specificity, followed by a period of remodeling. Lesions of the central nervous system occurring during development will affect these developmental processes at different points in the sequence and therefore have disparate effects on different portions of the brain at any given time of occurrence, as well as different effects depending on the time when the insult occurs. Unlike lesions occurring in the more steady-state condition of the adult nervous system, lesions during development have additional effects in redirecting subsequent development. It is arguable that this implies enhanced opportunities to mitigate the deleterious effects of such lesions. Potential therapeutic interventions can be divided by whether they are applied acutely, subacutely or late after injury. There are reasons for optimism regarding development of powerful new treatments in each of these categories. Further delineation of plasticity and the application of the resulting insights promise exciting and therapeutically important advances.