The directional organization of multiple nociceptive regions, particularly within obscure operculoinsular areas, underlying multidimensional pain processing remains elusive. This study aims to establish the fundamental organization between somatosensory and insular cortices in routing nociceptive information. By employing an integrated multimodal approach of high-field fMRI, intracranial electrophysiology, and transsynaptic viral tracing in rats, we observed a hierarchically organized connection of S1/S2 → posterior insula → anterior insula in routing nociceptive information. The directional nociceptive pathway determined by early fMRI responses was consistent with that examined by early evoked LFP, intrinsic effective connectivity, and anatomical projection, suggesting fMRI could provide a valuable facility to discern directional neural circuits in animals and humans non-invasively. Moreover, our knowledge of the nociceptive hierarchical organization of somatosensory and insular cortices and the interface role of the posterior insula may have implications for the development of targeted pain therapies.

中文翻译：

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体感皮质和岛叶皮质之间分层伤害感受路由路径的功能磁共振成像、LFP 和解剖学证据

多个伤害性区域的定向组织，特别是在模糊的岛盖区域内，潜在的多维疼痛处理仍然难以捉摸。本研究旨在建立体感皮质和岛叶皮质之间传递伤害性信息的基本组织。通过在大鼠中采用高场功能磁共振成像、颅内电生理学和跨突触病毒追踪的综合多模态方法，我们观察到 S1/S2→后岛叶→前岛叶在传递伤害性信息时存在分层组织的连接。早期 fMRI 反应确定的定向伤害感受通路与早期诱发的 LFP、内在有效连接和解剖投影所检查的一致，表明 fMRI 可以提供有价值的工具来非侵入性地辨别动物和人类的定向神经回路。此外，我们对体感和岛叶皮质的伤害感受分层组织以及后岛叶的界面作用的了解可能对靶向疼痛治疗的发展具有影响。