Our Understanding of Movement Is on the Move
Monday, January 14, 2008
How our brain controls our movements is a bit more complex and varied than scientists have previously recognized, according to research recently published in Science by a team of scientists and physicians at the University of Rochester Medical Center.
The team led by neurologist Marc Schieber, M.D., Ph.D., professor of Neurology and of Neurobiology & Anatomy, showed that at least occasionally, the brain is able to bypass the usual route of nerve fibers it uses for controlling hand and finger movements, using an alternate route to send its signals. Such flexibility in controlling movement has been suspected but not actually shown before.
“There are a number of different systems within the nervous system that normally cooperate to allow us to make movements,” said Schieber. “Our finding is that the major system that sends signals from the brain to motor neurons in the spinal cord does not necessarily dominate control of the movement all the time.
“This particular result tells us there might be a ray of hope for some patients who have suffered a brain injury. If the brain can produce movement through more than one system, we may be better able to rehabilitate people who have had a stroke that affects the cortex but leaves other pathways intact and functioning,” added Schieber, who also cares for patients on the Brain Injury Rehabilitation Unit at St. Mary’s Hospital.
Schieber is widely recognized as an expert in how the brain controls our movements, particularly hand and finger movements, and is the founder of the Finger Movement Laboratory at the University of Rochester Medical Center. The signals that generate movement are spread across several regions of the brain, including the cerebral cortex, the basal ganglia, the cerebellum, and the brainstem.
Scientists have believed that when the cerebral cortex sends a command to move, the signals go to motor neurons in the spinal cord, which then actually make our muscles move. In the Science paper published Dec. 21, Schieber and colleagues showed that sometimes, the signals can follow a different route from the brain to the spinal motor neurons.
“The nervous system is incredibly complex,” said Schieber. “Many parts of this vast signaling network can control our movements. We’re just trying to understand the basics in a way that will help patients like those who have had stroke, head trauma, or other nervous system injury.”
Other authors of the paper include post-doctoral researcher Adam Davidson, Ph.D.; Ryan O’Dell, a former University of Rochester undergraduate who is now in the M.D./Ph.D. program at Syracuse University; and Vanessa Chan, another former Rochester undergraduate also in an M.D./Ph.D. program, at the University of Pittsburgh.
The work was funded by a Senator Jacob Javits Investigator Merit Award to Schieber from the National Institute of Neurological Disorders and Stroke.