While TMS offers the advantages of relative safety and noninvasiveness, the results of its use in both research and treatment have been disappointing. In human studies, neurological effects of TMS have been transient, rarely lasting longer than 30 minutes.
Now, researchers led by John Rothwell of the Institute of Neurology at University College London have devised a new TMS method that produces rapid, consistent, and controllable changes in the motor cortex of humans that last more than an hour. Their findings offer the potential for both more useful research studies using TMS as well as greater therapeutic application.
In their studies, the researchers applied various patterns of repetitive magnetic pulses to the scalps of volunteer subjects. They aimed the pulses at the motor cortex that controls muscle response, because effects on the motor cortex can be objectively measured by recording the amount of electrical muscle response to stimulation. Specifically, the researchers positioned the magnetic coil over the motor cortex area that controls hand movement, and they measured response by determining the amount of muscle response in a small muscle in the subjects' hands.
The researchers recognized the ethical issue of experimenting on healthy human subjects who had nothing to gain from such experiments. So, they began their studies with stimulations of smaller intensities and lower frequencies than they ultimately used in the experiments. Those initial tests showed that there were no long-lasting or side effects from such stimulations.
In their experiments, the
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Contact: Heidi Hardman
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617-397-2879
Cell Press
19-Jan-2005