Bäumer T, Dammann E, Bock F, Klöppel S, Siebner H R, Münchau A
Department of Neurology, University of Hamburg, Martinstrasse 52, 20246 Hamburg, Germany.
Exp Brain Res. 2007 Jun;180(2):195-203. doi: 10.1007/s00221-007-0866-7. Epub 2007 Feb 8.
There is some evidence that handedness is related to lateralisation of excitability in the motor system. We investigated lateralisation of interhemispheric inhibition (IHI), motor thresholds and short interval intracortical inhibition (SICI) and facilitation (SICF) in relation to handedness in 12 right (RH) and 13 left handed (LH) subjects. Because there is some controversy as to the optimal localisation to produce IHI we also compared IHI induced by conditioning the dorsal premotor cortex (dPM) versus primary motor cortex (M1) in ten RH. IHI was stronger following conditioning the motor dominant as compared to the motor non-dominant hemisphere in RH and LH. Motor thresholds were higher when elicited over the right hemisphere than over the left in both RH and LH, while SICI and SICF showed no differences between hemispheres or dependency from handedness. We hypothesize that IHI is a function of handedness perhaps reflecting predominant usage of the dominant hand, while lateralisation of thresholds and intracortical excitability are determined by other factors.
有证据表明，利手与运动系统中兴奋性的偏侧化有关。我们研究了12名右利手（RH）和13名左利手（LH）受试者的半球间抑制（IHI）、运动阈值以及短间隔皮质内抑制（SICI）和易化（SICF）与利手的关系。由于在产生IHI的最佳定位方面存在一些争议，我们还比较了在10名右利手受试者中，通过刺激背侧运动前皮质（dPM）与初级运动皮质（M1）所诱导的IHI。在右利手和左利手受试者中，与运动非优势半球相比，刺激运动优势半球后IHI更强。在右利手和左利手受试者中，右侧半球诱发的运动阈值均高于左侧半球，而SICI和SICF在半球间无差异，也不依赖于利手。我们推测，IHI是利手的一种功能，可能反映了优势手的主要使用情况，而阈值和皮质内兴奋性的偏侧化则由其他因素决定。
