Control of Movement: Reticulospinal circuits

Perhaps the most fundamental thing we do is move - whether in speaking, in playing the piano or dancing, or lifting weights. Large parts of our central nervous systems are wired to ensure that we move appropriately for the task at hand. But how are we wired to move? There are multiple brain circuits involved. Some do the planning, make the decision, and select the appropriate movement. These circuits tell "command" neurons in the brain stem which movement to perform, and these neurons inform our organising circuits in the spinal cord that in turn tell our motor neurons how strongly to activate muscles. In this application, I propose to study command circuits - those between the brain stem and the spinal cord. These neurons live in a crowded place in the brain stem, the reticular formation. Some of these neurons are wired to prevent movement, whereas others are wired to cause movement. For example, prevention of movement is necessary when we dream, so reticular formation neurons that prevent movement are activated in REM sleep. Others are activated to initiate walking. I will use a variety of techniques (for example: genetic manipulations, electrical recordings, advanced microscopy of living tissue) to study the organisation of such "OFF" and "ON" systems, with the aim of better understanding how we move. As many neurologic diseases and injuries affect movement - for example, spinal cord injury, traumatic brain injury, multiple sclerosis, dystonia, stroke, movement disorders, and other neurodegenerative diseases - this work has broad implications. This research does not aim to cure any specific disorder, but rather to develop strategies to improve the quality of life of people with any neurological diseases or injuries that affect movement. At the end of the proposed 5 years, we will have enhanced understanding of the organisation of motor command neurons in the reticular formation, and of the relationship between moving and not moving.