Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA Department of Endodontics, Prosthodontics and Operative Dentistry, Baltimore College of Dental Surgery, Baltimore, MD, USA.
Pain. 2011 Jun;152(6):1398-1407. doi: 10.1016/j.pain.2011.02.025. Epub 2011 Mar 10.
Electrical stimulation of the primary motor cortex has been used since 1991 to treat chronic neuropathic pain. Since its inception, motor cortex stimulation (MCS) treatment has had varied clinical outcomes. Until this point, there has not been a systematic study of the stimulation parameters that most effectively treat chronic pain, or of the mechanisms by which MCS relieves pain. Here, using a rodent model of central pain, we perform a systematic study of stimulation parameters used for MCS and investigate the mechanisms by which MCS reduces hyperalgesia. Specifically, we study the role of the inhibitory nucleus zona incerta (ZI) in mediating the analgesic effects of MCS. In animals with mechanical and thermal hyperalgesia, we find that stimulation at 50 μA, 50 Hz, and 300 μs square pulses for 30 minutes is sufficient to reverse mechanical and thermal hyperalgesia. We also find that stimulation of the ZI mimics the effects of MCS and that reversible inactivation of ZI blocks the effects of MCS. These findings suggest that the reduction of hyperalgesia may be due to MCS effects on ZI. In an animal model of central pain syndrome, motor cortex stimulation reduces hyperalgesia by activating zona incerta and therefore restoring inhibition in the thalamus.
自 1991 年以来，人们一直利用初级运动皮层的电刺激来治疗慢性神经性疼痛。自成立以来，运动皮层刺激（MCS）治疗的临床效果各不相同。到目前为止，还没有系统地研究哪些刺激参数能最有效地治疗慢性疼痛，也没有研究 MCS 缓解疼痛的机制。在这里，我们使用一种中枢性疼痛的啮齿动物模型，对 MCS 中使用的刺激参数进行了系统研究，并研究了 MCS 减轻痛觉过敏的机制。具体来说，我们研究了抑制性核团中间带（ZI）在介导 MCS 的镇痛作用中的作用。在机械和热痛觉过敏的动物中，我们发现，用 50 μA、50 Hz 和 300 μs 方波脉冲刺激 30 分钟足以逆转机械和热痛觉过敏。我们还发现，ZI 的刺激模拟了 MCS 的效果，而 ZI 的可逆失活阻断了 MCS 的效果。这些发现表明，痛觉过敏的减少可能是由于 MCS 对 ZI 的影响。在中枢性疼痛综合征的动物模型中，运动皮层刺激通过激活中间带而减少痛觉过敏，从而恢复丘脑的抑制。
