Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
Brain Stimul. 2014 Mar-Apr;7(2):269-74. doi: 10.1016/j.brs.2013.12.009. Epub 2013 Dec 19.
The primary somatosensory cortex (SI) is important for hand function and has direct connectivity with the primary motor cortex (M1). Much of our present knowledge of this connectivity and its relevance to hand function is based on animal research. In humans, less is known about the neural mechanisms by which SI influences motor circuitry that outputs to the muscles controlling the hand.
The present study investigated the influence of SI on corticospinal excitability, and inhibitory and excitatory intracortical neural circuitry within M1 before and after continuous theta-burst stimulation (cTBS). Motor-evoked potentials (MEPs), short-latency intracortical inhibition (SICI) and intracortical facilitation (ICF) were recorded from the first dorsal interosseous (RFDI) muscle of the right hand following 30 Hz cTBS over left-hemisphere SI and M1 delivered in separate sessions.
cTBS over SI facilitated MEPs and did not alter ICF or SICI. cTBS delivered over M1 suppressed MEPs and ICF and did not alter SICI.
These findings indicate that SI influences corticospinal output to the hand, possibly via corticocortical projections, and may be one mechanism by which somatosensory information influences hand control.
初级躯体感觉皮层（SI）对手的功能很重要，并且与初级运动皮层（M1）有直接的连接。我们目前对这种连接及其对手的功能的相关性的大部分了解都基于动物研究。在人类中，关于 SI 如何影响输出到手部肌肉的运动回路的神经机制知之甚少。
本研究在连续 theta 爆发刺激（cTBS）前后，调查了 SI 对 M1 中皮质脊髓兴奋性以及抑制性和兴奋性内皮质神经回路的影响。在 30 Hz cTBS 分别施加于左侧半球的 SI 和 M1 后，从右手第一背间骨间肌（RFDI）记录运动诱发电位（MEP）、短潜伏期内皮质抑制（SICI）和内皮质易化（ICF）。
SI 上的 cTBS 促进了 MEP，并且没有改变 ICF 或 SICI。M1 上的 cTBS 抑制了 MEP 和 ICF，但没有改变 SICI。
这些发现表明，SI 通过皮质-皮质投射影响到手的皮质脊髓输出，这可能是感觉信息影响手部控制的一种机制。
