Dec. 10, 2002 St. Louis, Dec. 9, 2002 -- Brain regions involved in movement and feeling appear to remain relatively healthy and active even years after the body has been paralyzed, according to research at Washington University School of Medicine in St. Louis. A team of investigators found that five years after complete paralysis from a severe spinal cord injury, areas of the brain normally responsible for some movements and feelings have maintained those capabilities in one quadriplegic.
"The fact that there is stability in the brain despite a lack of input from the body is very good news," says Maurizio Corbetta, M.D., head of stroke and brain injury rehabilitation. "However, longer studies with more patients will have to be conducted to learn more about what this means for recovery after spinal cord injury."
Corbetta, who also is associate professor of neurology, of radiology and of anatomy and neurobiology, led the study along with Harold Burton, Ph.D., professor of anatomy and neurobiology, of cell biology and physiology and of radiology. The findings are scheduled to appear online the second week in December and in the Dec. 24 print issue of the Proceedings of the National Academy of Sciences.
Scientists have known for several years that a strip of the brain located roughly halfway between the front and back of the head becomes active during movement. Different areas along this strip become active when an individual moves different parts of his or her body. Some studies suggest that following amputation or blindness, the brain reorganizes so that areas no longer being used for one task – like vision – become rededicated to another task.
This study suggests, however, that severe spinal cord injury does not necessarily lead to extensive reorganization.
The team used functional magnetic resonance imaging (fMRI) to compare patterns of brain activity in one quadriplegic versus one healthy participant. The injured individual first was tested in 2000, shortly after he began to recover minimal movement, and again four more times over the following two years. His delayed recovery is detailed in the September 2002 issue of the Journal of Neurosurgery: Spine.
In the current study, brain images first were taken to measure participants' response to touch. A massage vibrator was applied either to the left hand or the left foot.
The second task tested brain activity during movement. Participants followed the image of a tennis ball with either their tongue or their left index finger. For example, as the ball moved up, participants moved their finger up; when the ball moved toward the left, participants moved their tongue to the left.
Brain activity during movement in the healthy individual was normal. Remarkably, patterns of brain activity in the individual with spinal cord injury also were normal, though slightly stronger and more widespread than in the healthy participant.
"Even though this individual had not been able to move for five years, motor patterns in the brain were relatively normal," says Burton. "That's very encouraging, because it means that this part of the brain doesn't disappear or lose its ability to function properly. The key might be that, though this individual's injury was extremely severe, a small portion of his spinal cord still is intact."
Similar to the strip of brain involved in movement, there also is an adjacent strip typically involved in sensing touch. During the vibration task, brain activity from the healthy participant was normal. The injured individual also had normal patterns of activity during foot vibration. However, hand vibration did not produce activity in the hand region on the right side of the brain, but instead resulted in activation in other areas, such as the right post-central sulcus and the posterior post-central gyrus. Moreover, tongue movements during the motor task resulted in activity in the normal hand region.
"Although there was some reorganization, we also found that a large part of the brain preserved its normal way of functioning," says Corbetta. "We never expected to see such dramatic conservation. It will be exciting to explore this further and try to understand the nervous system's ability to adapt to injury."
For further information please visit http://spine.wustl.edu.
Corbetta M, Burton H, Sinclair RJ, Conturo TE, Akbudak E, McDonald JW. Functional reorganization and stability of somatosensory-motor cortical topography in a tetraplegic subject with late neurological recovery. Proceedings of the National Academy of Sciences, December 2002.
Funding from the National Institute of Neurological Disorders and Stroke and the J. S. McDonnell Foundation supported this research.
The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
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