Differences between Han Chinese and Caucasians in transcranial magnetic stimulation parameters.
The study was conducted to investigate the difference between Han Chinese and Caucasians on various parameters measured from responses to transcranial magnetic brain stimulation (TMS). Sixteen subjects were studied in each group. A circular coil at the vertex was used for stimulation, whilst recording surface electromyograms from right first dorsal interosseous. In the passive state, motor-evoked potential (MEP) threshold, MEP recruitment, short-interval intracortical inhibition (SICI) and intracortical facilitation were measured. The MEP threshold, recruitment and silent period were also measured in the active state. Chinese subjects showed significantly higher passive thresholds (P < 0.005), less inhibition of the motor response (SICI, P < 0.0005) and a shorter silent period (P < 0.05). Differences in SICI appeared to be a consequence of the differences in passive threshold and were not seen when active threshold was used to determine the conditioning stimulus intensity. Differences in silent period may also reflect differences in cortical excitability rather than inhibitory processes, as they were not seen when the silent-period duration was expressed as a function of MEP size, rather than TMS intensity. There appears to be a significant difference in some TMS parameters between Han Chinese and Caucasian subjects. This may reflect an underlying difference in cortical excitability.
School of Mechanical and System Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
Xiang
X
Yi
Karen M
KM
Fisher
Ming
M
Lai
Kashif
K
Mansoor
R
R
Bicker
Stuart N
SN
Baker
D000328:Adult; D044466:Asian People / Q000208:ethnology; D001703:Biophysics; D003431:Cross-Cultural Comparison; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000235:genetics / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D050781:Transcranial Magnetic Stimulation; D044465:White People; D055815:Young Adult