Shaw N A
Department of Physiology, School of Medicine, University of Auckland, New Zealand.
Brain Res Bull. 1992 May;28(5):803-9. doi: 10.1016/0361-9230(92)90264-x.
Central Somatosensory conduction time (CSCT) in the rat was measured by simultaneously recording the cortical somatosensory evoked potential (SEP) and cervical SEP and then subtracting the peak latency of the cervical response from that of the primary cortical response. The low frequency (high pass) filter of the recording system was kept fixed at 3.2 Hz but the high frequency cut-off was progressively raised from 32 to 16 kHz to examine the effects of low pass filtering on the two waveforms from which CSCT is derived. With a bandpass of 3.2-32 Hz, no activity could be reliably identified in either the cortical or cervical traces. With subsequent rises in the high frequency filter, the amplitude of both potentials increased with a concomitant decrease in their latencies. Stable values were obtained with a bandpass of 3.2-3.2 kHz and there was little additional change in waveform configuration. In contrast to the waveforms, low pass filtering had only minimal effects on CSCT and near constant values (in the range 3.6-4.1 ms) were obtained regardless of the setting of the low pass filter. I concluded that low pass filtering has a largely uniform effect on somatosensory activity generated in both primary cortical and cervico-medullary locations.
通过同时记录大鼠的皮层体感诱发电位（SEP）和颈部SEP，然后用初级皮层反应的峰潜伏期减去颈部反应的峰潜伏期，来测量大鼠的中枢体感传导时间（CSCT）。记录系统的低频（高通）滤波器固定在3.2Hz，但高频截止频率从32kHz逐步提高到16kHz，以研究低通滤波对推导CSCT所依据的两种波形的影响。在3.2 - 32Hz的带通条件下，在皮层或颈部记录中均无法可靠地识别出活动。随着高频滤波器随后的升高，两种电位的幅度增加，同时潜伏期缩短。在3.2 - 3.2kHz的带通条件下获得了稳定值，并且波形配置几乎没有额外变化。与波形不同，低通滤波对CSCT的影响极小，无论低通滤波器的设置如何，都能获得接近恒定的值（在3.6 - 4.1ms范围内）。我的结论是，低通滤波对在初级皮层和颈髓部位产生的体感活动具有基本一致的影响。
