Instructive roles of neurotrophins in synaptic plasticity.

Together, these experiments show that neurotrophins regulate neuronal function in a factor-dependent fashion, both in terms of membrane excitability and dendritic growth, and indicate that neurotrophins can play instructive roles in regulating neuronal phenotype and function. Given that neurons generally receive neurotrophic inputs from many different cellular sources, both regional and distant (e.g., via axonal and dendritic projections), instructive actions of neurotrophic factors may contribute to matching the morphology and electrical function of neurons to the neural circuits of which they are part. Moreover, during ongoing development and function of the nervous system, these same or similar neurotrophic factors may be key instructive signals in regulating synaptic plasticity of neural circuits.