Urasaki E, Wada S, Yokota A, Tokimura T, Yasukouchi H
Department of Neurosurgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
J UOEH. 1993 Jun 1;15(2):113-35. doi: 10.7888/juoeh.15.113.
To identify the origin of short latency somatosensory evoked potentials (SSEPs) to posterior tibial nerve stimulation, direct recordings were made from the cervical cord, the ventricular system and the frontal subcortex during 8 neurosurgical operations. The origin of each component of SSEPs was also studied in 7 selected patients with various lesions in the central nervous system. In addition, SSEPs to median nerve stimulation were investigated in 4 of 8 surgical cases and all 7 cases of the lesion study group. Bilateral posterior tibial nerve stimulation in 10 normal subjects showed spinal N28 on the skin of the posterior neck and far-field P30 and N33 components followed by a cortical P38 component at the scalp. Direct recordings made to the mid-brain through the medulla oblongata showed a negative potential with gradually increasing latency. The peak of the negativity in the vicinity of the dorsal column nucleus showed almost the same latency as that of the scalp far-field P30, and positivity with a stationary peak was found above the dorsal column nucleus. Above the mid-pons, there was a stationary negativity with no latency shift, showing the same peak latency as that of scalp N33. The spatiotemporal distributions of P30 and N33 to posterior tibial nerve stimulation were analogous to those of P14 and N18 by median nerve stimulation. Transesophageal and direct cervical cord recordings showed that the spinal N13 phase to median nerve stimulation was reversed between the dorsal and ventral sides of the cervical cord. No such reversal occurred for the spinal N28 potential. Clinical lesion studies showed that changes in P30 and P14, and in N33 and N18 correlated with one another: that is, 1) prolongation of latency of N33 was also observed for N18; 2) absence of P30 was paralleled by the absence of P14. These data suggest that spinal N28 originates from ascending activity such as a dorsal column volley, and scalp P30 comes from activity near the dorsal column nucleus, which is similar to the P14 component of median nerve stimulation. The origin of N33 is thought to be similar to N18 from median nerve stimulation, which originates from brainstem activity below the thalamus.
为确定胫后神经刺激引发的短潜伏期体感诱发电位（SSEPs）的起源，在8例神经外科手术过程中，对颈髓、脑室系统和额叶皮质下进行了直接记录。还对7例中枢神经系统有不同病变的选定患者的SSEPs各成分的起源进行了研究。此外，在8例手术病例中的4例以及病变研究组的所有7例病例中，对正中神经刺激引发的SSEPs进行了研究。对10名正常受试者进行双侧胫后神经刺激，在后颈部皮肤记录到脊髓N28，随后在头皮记录到远场P30和N33成分，接着是皮质P38成分。通过延髓向中脑进行直接记录显示出一个潜伏期逐渐延长的负电位。在背柱核附近负电位的峰值与头皮远场P30的潜伏期几乎相同，并且在背柱核上方发现了具有稳定峰值的正电位。在脑桥中部上方，存在一个无潜伏期变化的稳定负电位，其峰值潜伏期与头皮N33相同。胫后神经刺激引发的P30和N33的时空分布与正中神经刺激引发的P14和N18相似。经食管和直接颈髓记录显示，正中神经刺激引发的脊髓N13期在颈髓背侧和腹侧之间发生了反转。脊髓N28电位未发生这种反转。临床病变研究表明，P30和P14以及N33和N18的变化相互关联：即，1）N18也观察到N33潜伏期延长；2）P30缺失与P14缺失并行。这些数据表明，脊髓N28起源于诸如背柱冲动等上行活动，头皮P30来自背柱核附近的活动，这与正中神经刺激的P14成分相似。N33的起源被认为与正中神经刺激的N18相似，后者起源于丘脑以下的脑干活动。
