Rizzo Vincenzo, Aricò Irene, Mastroeni Claudia, Morgante Francesca, Liotta Giovanna, Girlanda Paolo, Silvestri Rosalia, Quartarone Angelo
Department of Neurosciences, Psychiatry, and Anaesthesiological Science, University of Messina, Messina, Italy.
Mov Disord. 2009 Apr 15;24(5):710-5. doi: 10.1002/mds.22436.
In the present work, we aimed at assessing whether patients with idiopathic restless legs syndrome (RLS) showed alterations of sensory-motor plasticity, an indirect probe for motor learning, within the motor cortex (M1). Previous findings suggest that learning in human M1 occurs through LTP-like mechanisms. To test our hypothesis, we employed the paired associative stimulation (PAS) protocol by transcranial magnetic stimulation (TMS), which is able to induce LTP-like effects in the motor cortex of normal subjects. Twelve patients with idiopathic RLS and 10 age- and sex-matched control subjects were recruited. PAS protocol consisted of 0.05 Hz electrical median nerve stimulation (90 stimuli), paired with 0.05 Hz TMS (90 stimuli) over the hot spot for stimulating the abductor pollicis brevis (APB) muscle given 25 milliseconds after the onset of the electrical stimulus. Corticospinal excitability recorded in APB muscle, as indexed by MEP obtained after single stimulus, was tested before and up to 30 minutes after PAS protocol. Eight of 12 patients were studied before and after 4 weeks of dopaminergic treatment. PAS protocol increased significantly corticospinal excitability as long as 30 minutes in healthy subjects. On the contrary, PAS protocol did not change the amplitude of MEPs in patients with idiopathic RLS without treatment. PAS associative plasticity was restored after 4 weeks of dopaminergic treatment. Our data demonstrated that associative sensory-motor plasticity, an indirect probe for motor learning, is impaired in idiopathic RLS patients but may be reverted to normal after dopaminergic treatment.
在本研究中，我们旨在评估特发性不宁腿综合征（RLS）患者的感觉运动可塑性是否发生改变，感觉运动可塑性是运动学习的一种间接指标，我们对运动皮层（M1）进行了研究。先前的研究结果表明，人类M1中的学习是通过类似长时程增强（LTP）的机制发生的。为了验证我们的假设，我们采用经颅磁刺激（TMS）的配对联想刺激（PAS）方案，该方案能够在正常受试者的运动皮层中诱导出类似LTP的效应。招募了12例特发性RLS患者和10例年龄及性别匹配的对照受试者。PAS方案包括以0.05 Hz的频率电刺激正中神经（90次刺激），并在电刺激开始后25毫秒，于刺激拇短展肌（APB）的热点部位施加0.05 Hz的TMS（90次刺激）。在PAS方案实施前及实施后长达30分钟的时间内，检测以单次刺激后获得的运动诱发电位（MEP）为指标的APB肌肉中的皮质脊髓兴奋性。12例患者中有8例在接受4周多巴胺能治疗前后进行了研究。PAS方案在健康受试者中可使皮质脊髓兴奋性显著增加长达30分钟。相反，在未接受治疗的特发性RLS患者中，PAS方案并未改变MEP的幅度。在接受4周多巴胺能治疗后，PAS联想可塑性得以恢复。我们的数据表明，作为运动学习间接指标的联想感觉运动可塑性在特发性RLS患者中受损，但在多巴胺能治疗后可能恢复正常。
