Identification of the brainstem nuclei in the ascending viscerosensory system leading to the somatosensory cortex with the optical mapping

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K09481
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56010:Neurosurgery-related
• Research Institution: Shimane University
• Principal Investigator: Ito Shin-ichi 島根大学, 医学部, 特別協力研究員 (10145295)
• Co-Investigator(Kenkyū-buntansha): 横田 茂文 島根大学, 学術研究院医学・看護学系, 准教授 (50294369) ; 濱 徳行 島根大学, 学術研究院医学・看護学系, 助教 (60422010)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 内臓感覚 / 体性感覚 / 痛覚 / 電場電位 / 脳幹 / 中継核

Outline of Final Research Achievements

There are two somatic areas principally involved in pain and/or thermal sense in the rat cerebral cortex, beside the well-established somatosensory cortices. We investigated the corticopetal ascending pathway(s) of this newly identified sensory system, at subthalamic level. A brainstem region, formerly considered part of the trigeminal system, was found to be the relay nucleus of this system. Activation of high-threshold, slow conducting primary somatic afferents, irrespective of the body site, evoked a response in this region. Microstimulation of this region, in turn, evoked a response simultaneously in both the cortical areas. Finally, a lesion located in this region diminished the somatically evoked response in both the cortical areas. It appears that the output of this single brainstem region bifurcates, leading to the two cortical areas.

Free Research Field

神経生理学

Academic Significance and Societal Importance of the Research Achievements

機能画像法によりヒトの大脳皮質に痛覚関連領野がいくつか見いだされたが、その拠って立つ神経回路が不明なためその本態の理解は進んでいない。ほぼ同時期にサルにおいて島皮質と体性感覚皮質に痛覚・温度感覚専門の領野が見いだされ、それぞれの求心路も明らかにされたが、なお格段の伸展は見なかった。近年の神経科学の趨勢に鑑みて齧歯類での研究が必要と思われる。本研究はラットを用いて皮質２領野を頂点とする新たな身体感覚系の求心路をほぼ明らかにした。この感覚系の機能を解明し、ひいては臨床における痛覚制御への応用を図る上で本研究の成果は基礎を与えるものである。