Laboratoire d'Imagerie & Neurosciences Cognitives, UMR 7237, Université de Strasbourg-CNRS, 21 rue Becquerel-67087, France.
Clin Neurophysiol. 2011 May;122(5):1042-7. doi: 10.1016/j.clinph.2011.01.046. Epub 2011 Feb 25.
To verify the possibility of selective activation of C-fibers by a 5-Hz transcutaneous electrical stimulus.
Because Aβ-, Aδ- and C-fibers have different conduction velocities, we verified the selective activation of A- and C-fibers on the basis of evoked potential latencies. We tested whether a 5-Hz sinusoidal electric stimulus could selectively activate C-fibers and consequently generate ultra-late N2/P2 components in the 750-1200 ms range.
We found that a 5-Hz sine wave stimulus, whether of high or low intensity, elicited N2/P2 complexes only in the late latencies (160-390 ms), suggesting that A-fibers were concomitantly activated along with C-fibers.
These findings are in agreement with those of previous simulation studies suggesting that activation of fibers of diameter less than 2.5 μm (i.e., C-fibers) at the 5-Hz frequency requires accompanying activity from Aβ- and Aδ-fibers.
Transcutaneous electrical stimulation with sine wave currents of different frequencies does not seem to be a reliable method for the selective assessment of somatosensory pathways.
验证 5Hz 经皮电刺激选择性激活 C 纤维的可能性。
由于 Aβ、Aδ 和 C 纤维具有不同的传导速度，我们根据诱发电位潜伏期来验证 A 和 C 纤维的选择性激活。我们测试了 5Hz 正弦电刺激是否可以选择性地激活 C 纤维，并随后在 750-1200ms 范围内产生超晚 N2/P2 成分。
我们发现，5Hz 正弦波刺激，无论是高强度还是低强度，仅在晚期潜伏期（160-390ms）引发 N2/P2 复合波，这表明 A 纤维与 C 纤维同时被激活。
这些发现与之前的模拟研究结果一致，表明在 5Hz 频率下激活直径小于 2.5μm 的纤维（即 C 纤维）需要 Aβ 和 Aδ 纤维的伴随活动。
不同频率的经皮正弦电流电刺激似乎不是一种可靠的方法，不能用于选择性评估体感通路。
