Rachidi Inès, Minotti Lorella, Martin Guillaume, Hoffmann Dominique, Bastin Julien, David Olivier, Kahane Philippe
CHU Grenoble Alpes, 38000 Grenoble, France.
Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000 Grenoble, France.
Brain Sci. 2021 Nov 19;11(11):1533. doi: 10.3390/brainsci11111533.
Direct cortical stimulation (DCS) in epilepsy surgery patients has a long history of functional brain mapping and seizure triggering. Here, we review its findings when applied to the insula in order to map the insular functions, evaluate its local and distant connections, and trigger seizures. Clinical responses to insular DCS are frequent and diverse, showing a partial segregation with spatial overlap, including a posterior somatosensory, auditory, and vestibular part, a central olfactory-gustatory region, and an anterior visceral and cognitive-emotional portion. The study of cortico-cortical evoked potentials (CCEPs) has shown that the anterior (resp. posterior) insula has a higher connectivity rate with itself than with the posterior (resp. anterior) insula, and that both the anterior and posterior insula are closely connected, notably between the homologous insular subdivisions. All insular gyri show extensive and complex ipsilateral and contralateral extra-insular connections, more anteriorly for the anterior insula and more posteriorly for the posterior insula. As a rule, CCEPs propagate first and with a higher probability around the insular DCS site, then to the homologous region, and later to more distal regions with fast cortico-cortical axonal conduction delays. Seizures elicited by insular DCS have rarely been specifically studied, but their rate does not seem to differ from those of other DCS studies. They are mainly provoked from the insular seizure onset zone but can also be triggered by stimulating intra- and extra-insular early propagation zones. Overall, in line with the neuroimaging studies, insular DCS studies converge on the view that the insula is a multimodal functional hub with a fast propagation of information, whose organization helps understand where insular seizures start and how they propagate.
在癫痫手术患者中，直接皮层刺激（DCS）在脑功能图谱绘制和癫痫发作诱发方面有着悠久的历史。在此，我们回顾其应用于岛叶时的研究结果，以绘制岛叶功能图谱、评估其局部和远距离连接，并诱发癫痫发作。对岛叶DCS的临床反应频繁且多样，呈现出部分分离且有空间重叠的情况，包括后部的躯体感觉、听觉和前庭部分，中央的嗅觉 - 味觉区域，以及前部的内脏和认知 - 情感部分。皮质 - 皮质诱发电位（CCEP）的研究表明，前（相应地，后）岛叶与自身的连接率高于与后（相应地，前）岛叶的连接率，并且前岛叶和后岛叶都紧密相连，特别是在同源的岛叶亚区之间。所有岛叶回都显示出广泛而复杂的同侧和对侧岛叶外连接，前岛叶在更靠前的区域，后岛叶在更靠后的区域。通常，CCEP首先以较高概率在岛叶DCS部位周围传播，然后传播到同源区域，随后以快速的皮质 - 皮质轴突传导延迟传播到更远端的区域。由岛叶DCS诱发的癫痫发作很少被专门研究，但其发生率似乎与其他DCS研究的发生率没有差异。它们主要由岛叶癫痫发作起始区诱发，但也可通过刺激岛叶内和岛叶外的早期传播区触发。总体而言，与神经影像学研究一致，岛叶DCS研究一致认为岛叶是一个具有快速信息传播的多模态功能枢纽，其组织结构有助于理解岛叶癫痫发作的起始位置及其传播方式。
