Desmedt J E, Cheron G
Electroencephalogr Clin Neurophysiol. 1983 Dec;56(6):635-51. doi: 10.1016/0013-4694(83)90031-7.
Somatosensory evoked potentials (SEPs) were elicited by stimulation of the right posterior tibial nerve at the ankle in 20 experiments on 18 normal adults. A non-cephalic reference on the left knee was used throughout (with triggering of averaging cycles from the ECG), except for recording the peripheral nerve potentials. The responses were recorded along the spine, from oesophageal probes and from the scalp. The peripheral nerve volley propagated at a mean maximum conduction velocity (CV) of 59.2 m/sec served to identify the spinal entry time (mean 19.7 msec) at spinal segments S1-S3, under the D12 spine. This entry time coincided with the onset of the N21 component which was interpreted as the dorsal column volley and considered equivalent to the neck N11 of the median nerve SEP. The large voltage of the spinal response at the D12 spine probably results from summation of N21 with a fixed latency N24 potential that phase reverses at oesophageal recording sites into a P24. The N24-P24 reflects a horizontal dipole in the dorsal horn and is equivalent to the N13-P13 of the neck SEP to median nerve stimulation. Spinal conduction between D12-C7 spines was spuriously overestimated because the true length of the dorsal spinal cord is shorter by about 13% than the distance measured on the skin over the dorsal convexity. This correction should be applied routinely and it leads to a mean maximum spinal CV of 57 m/sec. Several positive far fields with widespread scalp distribution and stationary latencies have been identified. The P17 (over spine and head) reflects the peripheral nerve volley at the upper buttock. The P21 is synchronous with the N21 at the D12 spine and reflects the initial volley in the dorsal column. No far-field equivalent has been found for the N24-P24, due to the horizontal axis of the corresponding dipole. The P26 far field reflects the ascending volley at spinal levels D10-D4. The P31 reflects the initial volley in the medial lemniscus. The P40 at Cz represents the cortical response of the foot projection. Average central CVs were calculated and discussed.
在对18名正常成年人进行的20项实验中，通过刺激踝关节处的右胫后神经引出体感诱发电位（SEP）。除记录外周神经电位外，整个实验过程中均使用左膝处的非头部参考电极（并由心电图触发平均周期）。沿着脊柱、通过食管探头以及从头皮记录反应。外周神经冲动以平均最大传导速度（CV）59.2米/秒进行传导，用于确定脊髓节段S1 - S3在D12椎体水平的脊髓进入时间（平均19.7毫秒）。该进入时间与N21成分的起始时间一致，N21成分被解释为背柱冲动，被认为等同于正中神经SEP的颈部N11。D12椎体水平脊髓反应的高电压可能是由于N21与潜伏期固定的N24电位叠加所致，N24电位在食管记录部位发生相位反转成为P24。N24 - P24反映了背角中的水平偶极子，等同于颈部SEP对正中神经刺激的N13 - P13。D12 - C7椎体水平的脊髓传导被错误高估，因为脊髓背侧的实际长度比背部凸面皮肤测量的距离短约13%。应常规应用此校正，校正后脊髓平均最大CV为57米/秒。已识别出几个头皮分布广泛且潜伏期固定的正向远场。P17（在脊柱和头部上方）反映了上臀部的外周神经冲动。P21与D12椎体水平的N21同步，反映背柱中的初始冲动。由于相应偶极子的水平轴，未发现与N24 - P24等效的远场。P26远场反映了D10 - D4脊髓节段的上行冲动。P31反映内侧丘系中的初始冲动。Cz处的P40代表足部投射的皮质反应。计算并讨论了平均中枢CV。
