Cyclic peptides and peptidomimetics are provided that bind to and/or modulate activities associated with Trk receptors, including processes associated with the growth and repair of the central nervous system (e.g., neuronal growth and survival, axonal growth, neurite outgrowth and synaptic plasticity). Cyclic peptides and peptidomimetics are also provided that block or reduce the effect of other factors that inhibit growth and/or repair of the central nervous system. Pharmaceutical compositions and other formulations comprising these compounds are provided. In addition, the invention provides methods for using the cyclic peptides and peptidomimetics to modulate Trk mediated activities, including processes such as neuronal growth, survival and recover, axonal growth, neurite outgrowth, and synaptic plasticity. Further, the invention provides methods for promoting central nervous system (CNS) neuron growth by administering a p75 receptor binding agent.