Trophic factors: Neurotrophic factors

Neurotrophic factors support survival, process outgrowth, and phenotypic differentiation of neurons during development. Many neurotrophic factors are also expressed in adult brain, where they regulate neuronal connectivity and network plasticity. Neurotrophic factors are typically released from the target cells or postsynaptic neurons, taken up by the presynaptic axon terminals and retrogradely transported to the soma. Access of the axon terminal to neurotrophic factors selects among excessively generated neurons or neuronal processes for survival those that have established an optimal connection with the target cell, whereas neurons or processes with an insufficient access or transport of neurotrophic factors degenerate. Therefore, the primary function of neurotrophic factors is to mediate information to the neuronal soma about the quality of the connection between a neuron and its target. © Springer Science+Business Media, LLC 2013 and Springer Science+Business Media New York 2016.