Variation of reaction time can be reduced by the time locked application of magnetic stimulation of the motor cortex.
It was the aim of this study to determine the influence of non-invasive magnetic stimulation on the performance of a visually induced reaction task. The experiment was performed in 8 healthy volunteers. After a visual stimulus subjects had to move their thumbs as soon as possible. The muscular reaction was recorded with surface EMG on both sides. After the visual go-signal a magnetic stimulus (Fig. 8 coil) was applied above the right or left motor cortex at varying time intervals (30 and 110 ms). The magnetic stimulus was randomly given or not. Short time intervals between visual and magnetic stimulus induced a shortening, long intervals induced a prolongation of the reaction time. The contralateral reaction time was always longer than the ipsilateral one. Compared with the reaction times without magnetic stimulation, the intraindividual standard deviation of the reaction times was markedly reduced by the application of the magnetic stimulation. This reduction was greater in ipsilateral than in contralateral recordings. The kind of the instruction had additional modifying effects.
Masur
H
H
Department of Neurology, University of Münster, Germany.
Schneider
U
U
Papke
K
K
Oberwittler
C
C
D005071:Evoked Potentials; D006801:Humans; D008280:Magnetics; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement; D018482:Muscle, Skeletal / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D013933:Thumb / Q000502:physiology