Okada Y C, Williamson S J, Kaufman L
Int J Neurosci. 1982 Jul;17(1):33-8. doi: 10.3109/00207458208985086.
A magnetic field associated with voluntary finger flexion was found to be confined over a well-defined region of the scalp overlying the sensorimotor cortex contralateral to the finger. The magnetic field had opposite directions over two regions of the scalp superior and inferior to the classical finger area of the cortex, implying that the field was generated by a source or sources in this area. The field whose onset begins approximately 50 ms prior to muscle activation was associated with a cortical source lying about 2.8 cm beneath the scalp and the active area shifted posteriorly 3-6 mm into the somatosensory area during the finger movement. Consistent with this shift, the early component of the magnetic field prior to flexion of a finger was absent when it was passively moved by the finger of the opposite hand, but the later components were present.
研究发现，与手指自主弯曲相关的磁场局限于头皮上一个明确界定的区域，该区域位于与手指对侧的感觉运动皮层上方。在皮层经典手指区域上下的两个头皮区域，磁场方向相反，这意味着该磁场是由该区域内的一个或多个源产生的。该磁场在肌肉激活前约50毫秒开始出现，与位于头皮下方约2.8厘米处的皮层源相关，并且在手指运动过程中，活动区域向后移入体感区3 - 6毫米。与此移动一致的是，当手指被另一只手被动移动时，手指弯曲前磁场的早期成分消失，但后期成分仍存在。
