Human spinal interneurons repair the injured spinal cord through synaptic integration.

Advances in cell therapy offer promise for some of the most devastating neural injuries, including spinal cord injury (SCI). Endogenous VSX2-expressing spinal V2a interneurons have been implicated as a key component in plasticity and therapeutically driven recovery post-SCI. While transplantation of generic V2a neurons may have therapeutic value, generation of human spinal V2a neurons with rostro-caudal specificity and assessment of their functional synaptic integration with the injured spinal cord has been elusive.

Transneuronal tracing to map connectivity in injured and transplanted spinal networks.

It has become widely appreciated that the spinal cord has significant neuroplastic potential, is not hard-wired, and that with traumatic injury and anatomical plasticity, the networks that we once understood now comprise a new anatomy. Harnessing advances in neuroanatomical tracing to map the neuronal networks of the intact and injured spinal cord has been crucial to elucidating this new spinal cord anatomy. Many new techniques have been developed to identify these networks using a variety of retrograde and anterograde tracers.