Trk receptors are a family of tyrosine kinases that regulates synaptic strength and plasticity in the mammalian nervous system. Trk receptors affect neuronal survival and differentiation through several signal cascades. However, the activation of these receptors also has significant effects on functional properties of neurons. The three most common types of trk receptors are trkA, trkB, and trkC. Each of these receptor types has different binding affinity to certain types of neurotrophins. The differences in the signaling initiated by these distinct types of receptors are important for generating diverse biological responses. The activation of Trk receptors by neurotrophin binding may lead to activation of signal cascades resulting in promoting survival and other functional regulation of cells.