Jaw movement-related primary somatosensory cortical area in the rat
Jaw movement-related primary somatosensory cortical area in the rat
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大鼠下颌运动相关的初级体感皮质区
DOI：
10.1016/j.neuroscience.2014.09.072
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发表时间：
2015
期刊：
影响因子：
3.3
通讯作者：
Yoshida A
中科院分区：
文献类型：
--
作者：
Uchinoa K;Higashiyama K;Kato T;Haque T;Sato F;Tomita A;Tsutsumi K;Moritani M;Yamamura K;Yoshida A
解剖学揭示，大鼠初级体感皮层（S1）的头侧部分直接投射到三叉神经口腔亚核的背侧部分（dorVo）和近三叉神经区的背侧部分（dorVjuxt），并且dorVo和dorVjuxt包含直接投射到口腔中的开颌或闭颌运动神经元的前运动神经元。三叉神经运动核（Vmo）。然而，关于头侧 S1 如何调节与其皮质投射相关的下颌运动，人们知之甚少。为了解决这个问题，我们通过监测下颌运动和肌电图 (EMG) 活动对大鼠头侧 S1 进行皮质内微刺激。我们首次发现，对 S1 喙侧进行低频长训练刺激可诱导下颌单次持续张开，同时二腹肌前肌肌电图活动升高（下颌张开）。低频长序列刺激的有效部位与传统高频短序列刺激可有效诱导单次抽搐样下颌运动的 S1 部位重叠。我们还发现，这两种训练刺激的有效位点都包含在吻侧 S1 区域，该区域之前已被确定可向 dorVo 或 dorVjuxt 发送直接投影。具体来说，两种训练刺激最有效的刺激位点位于 S1 的最前端部分，据报道，该部位对 dorVjuxt 发出强烈的直接投射，但对 dorVo 的直接投射较少。因此，本研究表明，大鼠吻侧S1，特别是其吻侧部分，通过激活从吻侧S1到三叉神经前运动神经元池（特别是到dorVjuxt）的直接下降投射，在控制下颌运动中发挥重要作用。
It has anatomically been revealed that the rostral part of the rat primary somatosensory cortex (S1) directly projects to the dorsal part of the trigeminal oral subnucleus (dorVo) and the dorsal part of juxtatrigeminal region (dorVjuxt), and that the dorVo and dorVjuxt contain premotoneurons projecting directly to the jaw-opening or jaw-closing motoneurons in the trigeminal motor nucleus (Vmo). However, little is known about how the rostral S1 regulates jaw movements in relation to its corticofugal projections. To address this issue, we performed intracortical microstimulation of the rat rostral S1 by monitoring jaw movements and electromyographic (EMG) activities. We for the first time found that low-frequency long-train stimulation of the rostral S1 induced single sustained opening of the jaw with elevated EMG activities of the anterior digastric muscles (jaw-opener). The effective sites for the low-frequency long-train stimulation overlapped the S1 sites where traditional high-frequency short-train stimulation was effective to induce single twitch-like jaw movement. We also found that the effective sites for the two kinds of train stimuli were included in the rostral S1 area, which has previously been identified to send direct projections to the dorVo or the dorVjuxt. Specifically, the most effective stimulation sites for the two kinds of train stimuli were located in the rostralmost part of S1 which has been reported to emanate strong direct projections to the dorVjuxt but less to the dorVo. Therefore, the present study suggests that the rat rostral S1, especially its rostralmost part, plays an important role in controlling jaw movements by activation of direct descending projections from the rostral S1 to the trigeminal premotoneuron pools, especially to the dorVjuxt.