Mechanism and the treatment of central deafferentation pain

外周神经系统和中枢神经系统感觉通路的传入神经缺失已被证明会导致超过传入神经缺失水平的感觉通路内神经元的过度活跃。这种过度活跃与临床观察到的移行性疼痛机制有关。在本研究中；1)我们记录了脊髓丘脑束（STT）横断后丘脑核后外侧腹侧（VPL）内和VPL病变后丘脑核感觉皮层内的单个神经元活动。感觉皮层神经元在VPL病变后出现过度活跃，STT横断后VPL神经通过募集NMDA受体而出现过度活跃。运动皮层刺激可抑制VPL和感觉皮层神经元的过度活动。2)单侧病变局限于丘脑后腹基底区后，病变侧感觉运动皮层第4层CYO活性迅速下降。通常在第四层看到的与桶相对应的分段仍然没有出现。虽然在其他层也注意到较少的减少，但随后观察到明显的恢复。这些代谢活动的变化反映了皮层脱神经后神经回路的重组过程，丘脑疼痛有时由此产生。(3)在临床研究中，我们得出了传入神经缺失疼痛的药理学分类有助于发现传入神经缺失疼痛和预测慢性脑刺激治疗的效果。(4)基于这些结果，我们采用硬膜外板电极慢性运动皮质刺激治疗了12例丘脑疼痛综合征。疼痛控制良好，无并发症和副作用。

Deafferentation of the sensory pathways within the peripheral and central nervous systems has been demonstrated to cause hyperactivity of neurons within the sensory pathways above the level of deafferentation. Such hyperactivity has been implicated in the mechanism of deafferentation pain observed clinically. In this studies ; 1) We recorded single neuron activities within the thalamic nucleus ventralis posterolateralis (VPL) after transection of the spinithalamic tract (STT) and within the sensory cortex after VPL lesions. Sensory cortex neurons became hyperactive after VPL lesions, and VPL neurous became hyperactive after STT transection through recruitment of NMDA recetors. The hyperactibities of VPL and sonsory cortex neurons were inhibited by the motor cortex stimulation. 2) After unilateral lesions restricted to the posterior ventrobasal region of the thalamus, CYO activity decreased rapidly in layr IV of the sensorimotor cortex at lesioned side. Segmentations normally seen in layr IV corresponding to barrels remained absent. While less marked decreases were also noted in other layrs, obvious recovery was subsequently obserbed. These changes in metabolic activity reflect the process of reorganization of neural circuits after tha lamocortical deafferentation from which thalamic pain is sometime produced. 3) In clinical studies, we concluded that pharmacoligical classification of deafferentation pain is useful for finding the deafferentation pain and for predicting the efficiency of chronic brain stimuration therapy, 4) Based on these results, We treated 12 cases of thalamic pain syndrome by chronic motor cortex stimulation employing epidural plate electrodes. Good pain control was obtained without any complication and side effects.