Huttunen J, Kaukoranta E, Hari R
J Neurol Sci. 1987 Jun;79(1-2):43-54. doi: 10.1016/0022-510x(87)90258-9.
We report somatosensory evoked magnetic fields (SEFs) to stimulation of the mixed posterior tibial nerve (PTN) and the sensory sural nerve (SN) in 6 healthy subjects. The first peak of the responses occurred at 39-50 ms (P40m), with a 2-3 ms longer latency for SN than PTN stimulation. Within 200 ms several other deflections followed, with interindividually varying waveforms and latencies. Magnetic field mappings indicated that the source of P40m for PTN can be modelled by a single equivalent current dipole at the primary sensorimotor cortex; for the smaller responses to SN stimulation the single dipole model was less applicable. Field patterns for later deflections differed from those of P40m, indicating that several current sources within or near the primary foot projection area are sequentially activated after stimulation of both a mixed and a sensory lower limb nerve. These late deflections could not always be satisfactorily explained by single current dipoles, suggesting more complex geometries for the underlying neural activity.
我们报告了6名健康受试者在混合胫后神经（PTN）和感觉腓肠神经（SN）受到刺激时的体感诱发电场（SEF）情况。反应的第一个峰值出现在39 - 50毫秒（P40m），SN刺激的潜伏期比PTN刺激长2 - 3毫秒。在200毫秒内还出现了其他几个偏转，其波形和潜伏期因人而异。磁场映射表明，PTN的P40m源可以用初级感觉运动皮层的单个等效电流偶极子来建模；对于SN刺激产生的较小反应，单偶极子模型不太适用。后期偏转的场模式与P40m不同，表明在混合和感觉性下肢神经受到刺激后，初级足部投射区域内或附近的几个电流源会依次被激活。这些后期偏转不能总是用单个电流偶极子来令人满意地解释，这表明潜在神经活动的几何结构更为复杂。
