García-Larrea L, Peyron R, Mertens P, Grégoire M C, Lavenne F, Bonnefoi F, Mauguière F, Laurent B, Sindou M
CERMEP (Positron Emission Tomography Center), Lyon, France.
Stereotact Funct Neurosurg. 1997;68(1-4 Pt 1):141-8. doi: 10.1159/000099915.
We studied regional changes in cerebral flood flow (rCBF) in 9 patients undergoing motor cortex stimulation (MCS) for pain control. Significant increase in rCBF was observed in the lateral thalamus ipsilateral to MCS probably reflecting corticothalamic connections from motor/premotor areas. Subsignificant increases were observed in the anterior cingulate, left insula and upper brainstem. Mean rCBF in the anterior cingulate increased during MCS in patients with good analgesic efficacy, while it decreased in those with poor clinical outcome; conversely, thalamic rCBF increased in the two groups, albeit to a greater extent in patients with good clinical results. Our results support a model of MCS action whereby activation of thalamic nuclei directly connected with motor and premotor cortices would entail a cascade of synaptic events in other pain-related structures, including the anterior cingulate and the periaqueductal gray. MCS could influence the affective-emotional component of chronic pain by way of cingulate activation, and lead to descending inhibition of pain impulses by activation of the brainstem. Such effects may be obtained only if thalamic activation reaches a 'threshold' level, below which the analgesic cascade would not be successfully triggered.
我们研究了9例接受运动皮层刺激（MCS）以控制疼痛的患者的脑血流区域变化（rCBF）。在与MCS同侧的外侧丘脑观察到rCBF显著增加，这可能反映了来自运动/运动前区的皮质丘脑连接。在前扣带回、左侧岛叶和上脑干观察到不显著的增加。在镇痛效果良好的患者中，MCS期间前扣带回的平均rCBF增加，而在临床结果较差的患者中则降低；相反，两组丘脑rCBF均增加，尽管在临床效果良好的患者中增加幅度更大。我们的结果支持一种MCS作用模型，即与运动和运动前皮层直接相连的丘脑核的激活会在其他与疼痛相关的结构中引发一系列突触事件，包括前扣带回和导水管周围灰质。MCS可能通过扣带回激活影响慢性疼痛的情感-情绪成分，并通过激活脑干导致疼痛冲动的下行抑制。只有当丘脑激活达到“阈值”水平时，才能获得这种效果，低于该阈值则无法成功触发镇痛级联反应。
