Department of Rehabilitation, Université Laval, 1050 Avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), 525 Boul. Wilfrid-Hamel, Quebec City, QC, Canada G1M 2S8.
Neural Plast. 2018 Apr 26;2018:8713218. doi: 10.1155/2018/8713218. eCollection 2018.
Previous studies have shown that pain can interfere with motor control. The neural mechanisms underlying these effects remain largely unknown. At the upper limb, mounting evidence suggests that pain-induced reduction in corticospinal excitability is involved. No equivalent data is currently available at the lower limb. The present study therefore examined the effect of thermal pain on the corticospinal drive to tibialis anterior (TA) at rest and during an isometric submaximal dorsiflexion. Transcranial magnetic stimulation was used to induce motor-evoked potentials (MEPs) in the TA at rest and during contraction in the presence or absence of cutaneous heat pain induced by a thermode positioned above the TA (51°C during 1 s). With similar pain ratings between conditions (3.9/10 at rest and 3.6/10 during contraction), results indicate significant decreases in MEP amplitude during both rest (-9%) and active conditions (-13%) (main effect of pain, = 0.02). These results therefore suggest that cutaneous heat pain can reduce corticospinal excitability in the TA muscle and that such reduction in corticospinal excitability could contribute to the interference of pain on motor control/motor learning.
先前的研究表明，疼痛会干扰运动控制。这些影响的神经机制在很大程度上尚不清楚。在上肢，越来越多的证据表明，疼痛引起的皮质脊髓兴奋性降低与此有关。目前在下肢尚无等效数据。因此，本研究旨在检查热痛对胫骨前肌（TA）在休息和等长次最大背屈期间的皮质脊髓驱动的影响。使用经颅磁刺激在放置于 TA 上方的热模（51°C 持续 1 秒）引起的皮肤热痛存在或不存在的情况下，在休息和收缩期间诱导 TA 中的运动诱发电位（MEP）。在条件之间具有相似的疼痛评分（休息时为 3.9/10，收缩时为 3.6/10）时，结果表明 MEP 幅度在休息时（-9%）和主动时（-13%）均显着降低（疼痛的主要影响，= 0.02）。因此，这些结果表明，皮肤热痛可以降低 TA 肌肉中的皮质脊髓兴奋性，并且这种皮质脊髓兴奋性的降低可能导致疼痛对运动控制/运动学习的干扰。
