Functional mapping of brainstem-spinal motor circuits

Understanding how specific groups of neurons contribute to behaviour is a formidable challenge which in mammals requires studying extensive networks. Many motor networks encompass large areas of the central nervous system, mostly due to the presence of lo ng axonal connections such as those connecting the brain to the spinal cord. However, information about the neuronal circuitry involved (neuron identities and connectivity), remains largely unknown. Thus, methods that facilitate the identification of neur onal components of basic brainstem and spinal motor circuits will greatly advance our understanding of locomotion and other motor behaviors. Recent developments in functional neuroanatomy, molecular biology and genetics are now providing neuroscientists w ith new tools for dissecting neuronal networks. The aim of this proposal is to utilize some of these tools to identify synaptically connected neurons in the brain stem and spinal cord that constitute some of the main circuits involved in motor control. Ex change of technical expertise between the Norwegian and French research groups involved here will greatly promote each of the groups' efforts towards this common goal. The present proposal will advance our understanding of how brainstem-spinal cord net works are organized and function. This has substantial clinical relevance regarding the recovery of motor function after various types of injuries to the spinal cord and brain stem, including vascular, ischemic, neoplastic and traumatic insults. It should be noted that a better characterization of brainstem-spinal cord circuitry will greatly facilitate in particular efforts to promote re-growth, reconnection and synaptic reorganization of axons and their connections after spinal cord injury.