More MS news articles for Oct 2001

Quadriplegics Retain Ability to Activate Sensorimotor Brain Areas

WESTPORT, CT (Reuters Health) Oct 24 - Attempted movement of paralyzed limbs activates corresponding areas of motor cortex that differ little in somatotopic organization from those in nonparalyzed subjects, according to a brief communication in the October 25th issue of Nature.

This finding implies, the investigators say, that an implantable brain-computer interface device that could bypass damaged motor pathways to reconstruct complex voluntary motor activity would be feasible for patients with spinal cord injuries.

Dr. Richard A. Normann, of the University of Utah in Salt Lake City, and colleagues examined five subjects with C5-C6 trauma-related spinal-cord damage 1 to 5 years after their injuries, along with five healthy control subjects. All individuals were asked to move or attempt to move their hands, elbows, feet, left knee, and lips.

According to the results of functional magnet resonance imaging, volitional activation of cortical sensorimotor representations in the quadriplegics varied little from that of control subjects. The research team notes that this response in patients with paralysis meets one of the principal physiological requirements for the development of an implantable neuroprosthetic that could reconstruct complex voluntary motor activity.

In an interview with Reuters Health, Dr. Normann elaborated on his group's findings and their potential implications. He noted that, in an unimpaired individual, firing patterns of neurons in the motor cortex differ, for example, when one makes a fist and then opens the hand, or when different fingers are raised.

"We showed that a spinal cord-injured individual who is not able to cause movement can still think the same thoughts that activate the hand representation or the finger representation, and so on," he said. "The architectural arrangement and function of the motor cortex has been preserved even 5 years post-injury."

He continued, "That means that one could implant an array of electrodes into the motor cortex of a patient paralyzed by a spinal cord injury and record the firing patterns there. Then the person could modulate or control the firing pattern just by volitional thought. We would amplify those signals and send them out to a computer and use those recorded signals to control an external device, such as a wheelchair or a computer terminal or a robotic arm."

Nature 2001;413:793.

Copyright © 2001 Reuters Ltd