Somatic motor and sensory representation in the cerebral cortex of man as studied by magnetoencephalography and transcranial magnetic stimulation.

目的Penfield报道了人类大脑中感觉和运动表征的皮质图谱。在这些地形图中，大部分身体部位在中央沟面对面，但只有颈部分别位于运动皮质和感觉皮质之间，即运动皮质的手指和面部之间，感觉皮质的内侧到手指之间。我们认为这一事实与局灶性肌张力障碍的发生机制有关，如痉挛性斜颈和感觉特技。作为阐明这一临床问题的第一步，我们用脑磁图(MEG)和经颅磁刺激(TMS)对手指、面部和颈部的运动和感觉皮质进行了评估。脑磁图(MEG)和经颅多普勒超声(TMS)是一种新型的无创评估人脑功能的仪器。通过TMS的一分区标测，评估患者手指、面部和颈部运动区的位置。记录受试者第一背侧骨间肌(手指)、口轮匝肌(面部)和胸锁乳突肌(颈部)的运动诱发电位(MEP)。因此，运动皮质的手指和面部区域分别位于顶点外侧约5 cm和9 cm处，而颈部区域分别位于顶点外侧约3 cm和7 cm处。结果表明，运动皮质的颈部区域位于Penfield所报道的面向颈部和感觉皮质躯干区域的躯干区域附近，以及手指和面部区域之间。对10名健康受试者进行了电刺激腕部正中神经、手指皮肤和大鱼际肌运动点的体感诱发磁场(SEF)的脑磁图研究。正中神经刺激后20ms、30ms、40ms和60ms出现四个峰值，手指刺激后20ms和30ms出现两个峰值，60ms左右出现一个峰值。这些峰的等效电流偶极子均位于初级感觉皮层手部区域附近。

PurposePenfield reported cortical maps of sensory and motor representation in human brain. In these maps, most of body parts faced each other across central sulcus, but only neck was located separately in motor and sensory cortex, i.e. between finger and face in motor cortex and medial to finger in sensory cortex. We thought that this fact was associated with mechanism of focal dystonia, such as spasmodic torticollis, and sensory trick. As the first step to elucidate such a clinical question, we evaluated motor and sensory cortex of finger, face and neck by magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS). The MEG and TMS are new devices that can evaluate human brain function noninvasively.A TMS studyFive healthy subjects were participated. We evaluated the locations of their motor area of finger, face and neck used by one-divisional mapping of TMS. We recorded motor evoked potentials (MEPs) of subjects from first dorsal interosseis (finger), musculus orbicularis oris (face) and sternocleidomastoideus (neck). As a result, the finger and face area of motor cortex were located in about 5cm and 9cm lateral from vertex respectively, while the neck area was exist in about both 3cm and 7cm lateral to vertex, separately. Our results suggested that the neck area of motor cortex existed near the trunk area which faced the neck and trunk area of sensory cortex, as well as between finger and face area which reported by Penfield.A MEG studySomatosensory evoked magneticfields (SEF) were recorded in ten healthy subjects following to electrical stimulation of median nerve at wrist, skin of finger and motor point of thenar muscle. There were four peaks of SEF at about 20ms, 30ms, 40ms and 60ms after median nerve stimulation, two peaks at about 20ms and 30ms after finger stimulation, and a peak at about 60ms. The equivalent current dipoles of these peaks were all near the hand area of the primary sensory cortex.