Duysens J, Baken B C M, Burgers L, Plat F M, den Otter A R, Kremer H P H
Department of Biophysics, University Medical Center, University of Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Clin Neurophysiol. 2004 May;115(5):1057-62. doi: 10.1016/j.clinph.2003.12.006.
It is known that P2 cutaneous reflexes from the foot show phase-dependent modulation during gait. The role of the motor cortex and the cortico-spinal tract in these reflexes and their modulation is unknown. Patients with hereditary spastic paraparesis (HSP) have a lesion in the cortico-spinal tract and may show deficits in P2 reflexes and/or their modulation.
Reflex responses of tibialis anterior and biceps femoris after sural nerve stimulation in 10 HSP-patients were compared with those in 10 healthy subjects. The reflexes were studied at two different moments in the step cycle during walking on a treadmill.
Both patients and controls showed a phase-dependent modulation of P2 responses. For the individual muscles, no significant difference in reflex activity was observed between HSP-patients and the controls. However, when all muscles were taken together, the reflex activity for the controls was significantly higher than for the patients.
The results of this study suggest that the cortico-spinal tract is involved in the regulation of the amplitude of the P2 responses and their phase-dependent modulation.
已知足部的P2皮肤反射在步态期间呈现相位依赖性调制。运动皮层和皮质脊髓束在这些反射及其调制中的作用尚不清楚。遗传性痉挛性截瘫（HSP）患者的皮质脊髓束存在病变，可能在P2反射和/或其调制方面表现出缺陷。
将10例HSP患者在腓肠神经刺激后胫前肌和股二头肌的反射反应与10名健康受试者的反射反应进行比较。在跑步机上行走时，在步周期的两个不同时刻研究反射。
患者和对照组均表现出P2反应的相位依赖性调制。对于个体肌肉，HSP患者和对照组之间未观察到反射活动的显著差异。然而，当将所有肌肉综合考虑时，对照组的反射活动明显高于患者。
本研究结果表明，皮质脊髓束参与P2反应幅度的调节及其相位依赖性调制。
