From visual experience to visual function: Roles of neurotrophins

Recently, a role for neurotrophins in regulating cortical developmental pla sticity has clearly emerged. We present in this review a summary of the ear ly data on the action of nerve growth factor (NGF) in visual cortical devel opment and plasticity in the rat and of other neurotrophins in the visual c ortex of other mammals. In addition, to clarify the differences in the resu lts obtained with the various neurotrophins in different animal preparation s, we also report new data on the action of NGF, brain-derived neurotrophic factor (BDNF), neurotrophin (NT)3, and NT4 in the same preparation-namely, the visual cortex of the rat. We discuss old and new results in a physiolo gical model in which different neurotrophins play different roles in regula ting visual cortical development and plasticity by acting on different neur al targets, such as lateral geniculate nucleus (LGN) afferents, intracortic al circuitry, and subcortical afferents, and propose a tentative scheme sum marizing these actions. (C) 1999 John Wiley & Sons, Inc.