Tinazzi Michele, Stanzani Clementina, Fiorio Mirta, Smania Nicola, Moretto Giuseppe, Fiaschi Antonio, Edwards Mark J, Bhatia Kailash P, Rothwell John C
Dipartimento di Scienze Neurologiche e della Visione, Sezione di Neurologia Riabilitativa, Università di Verona, Italy.
Exp Brain Res. 2005 Oct;166(2):184-9. doi: 10.1007/s00221-005-2353-3. Epub 2005 Jul 14.
Percutaneous electrical stimulation of the motor point of the first dorsal interosseous muscle (FDI) was used to produce a non-painful contraction of the FDI muscle that caused index finger abduction movement but no radiating cutaneous paraesthesias or sharp sensations localized to joints. Pairs of stimuli separated by different time intervals were given and subjects were asked to report whether they perceived a single or a double index finger abduction movement. The threshold value was the shortest interval for which the subjects reported two separate index finger abduction movements. Temporal discrimination movement thresholds (TDMT) were measured for both right and left hand. To assess the possible role of muscle and cutaneous afferents in temporal discrimination, we investigated the effects of high-frequency (20 Hz) electrical stimulation of the right ulnar and radial nerves on TDMT. In humans, muscle afferents from FDI are supplied by the ulnar nerve whereas the cutaneous territory overlying the muscle and joint is supplied by the radial and median nerves. Threshold values were not significantly different for right (75.1 ms) and left (75.6 ms) hands. During ulnar and to a lesser extent during radial nerve stimulation, TDMT values were significantly increased (119.2 and 93.5 ms, respectively) compared with baseline conditions (78.0 ms) whereas no changes were observed during median nerve stimulation (80.5 ms). These results suggest that muscle, and in part cutaneous, afferents contribute to temporal discrimination of a dual movement. The technique may provide a useful way of measuring temporal discrimination of kinaesthetic inputs in humans.
经皮电刺激第一背侧骨间肌（FDI）的运动点，以产生FDI肌肉的无痛收缩，该收缩引起食指外展运动，但无放射状皮肤感觉异常或局限于关节的尖锐感觉。给予不同时间间隔分开的成对刺激，并要求受试者报告他们是否感知到单个或双个食指外展运动。阈值是受试者报告两个单独食指外展运动的最短间隔。测量了右手和左手的时间辨别运动阈值（TDMT）。为了评估肌肉和皮肤传入神经在时间辨别中的可能作用，我们研究了右尺神经和桡神经高频（20 Hz）电刺激对TDMT的影响。在人类中，FDI的肌肉传入神经由尺神经供应，而肌肉和关节上方的皮肤区域由桡神经和正中神经供应。右手（75.1毫秒）和左手（75.6毫秒）的阈值没有显著差异。在尺神经刺激期间以及在较小程度上在桡神经刺激期间，与基线条件（78.0毫秒）相比，TDMT值显著增加（分别为119.2和93.5毫秒），而在正中神经刺激期间（80.5毫秒）未观察到变化。这些结果表明，肌肉以及部分皮肤传入神经有助于对双重运动的时间辨别。该技术可能提供一种测量人类动觉输入时间辨别的有用方法。
