SPATIOTEMPORAL DYNAMICS OF EXCITATION IN RAT INSULAR CORTEX: INTRINSIC CORTICOCORTICAL CIRCUIT REGULATES CAUDAL-ROSTRO EXCITATORY PROPAGATION FROM THE INSULAR TO FRONTAL CORTEX
SPATIOTEMPORAL DYNAMICS OF EXCITATION IN RAT INSULAR CORTEX: INTRINSIC CORTICOCORTICAL CIRCUIT REGULATES CAUDAL-ROSTRO EXCITATORY PROPAGATION FROM THE INSULAR TO FRONTAL CORTEX
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DOI：
10.1016/j.neuroscience.2009.09.073
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发表时间：
2010-01-13
期刊：
影响因子：
3.3
通讯作者：
Kobayashi, M.
中科院分区：
文献类型：
--
作者：
Fujita, S.;Adachi, K.;Kobayashi, M.
岛叶皮层（IC）是丘脑感觉核团的多通道感觉输入，包括内脏、味觉和躯体感觉信息。边缘结构的轴突投射对癫痫活动的诱导具有深远的影响，也会聚到IC上。然而，IC的生理和病理作用特征的功能连接仍然不清楚。本研究试图阐明的时空动力学的兴奋性传播及其细胞机制的IC在光记录在麻醉大鼠。在50 Hz的IC的重复电刺激表现出兴奋性传播的特征模式取决于刺激部位。刺激IC（GI）的颗粒区和其他周围的皮质，如运动/初级感觉/次级感觉皮质诱发圆形的兴奋性传播，这往往延伸到相邻区域的边界，而在IC（AI和DI，分别）的无颗粒和dysgranular区的兴奋传播沿着与鼻裂平行的喙尾轴。刺激AI/DI经常诱发兴奋的背外侧眶皮层，表现出空间上不连续的地形兴奋性传播的IC。使用6，7-二硝基喹喔啉-2，3（1H，4 H）-二酮（DNQX）（一种非NMDA受体拮抗剂）、D-2-氨基-5-膦酰基戊酸（DAPV）（一种NMDA受体拮抗剂）和荷包牡丹碱甲碘化物（一种GAGA受体拮抗剂）的药理学操作表明，兴奋性传播主要受非NMDA和GABA受体调节。利多卡因的微量注射或切口的restrocaudally中间部分的兴奋性区域的颗粒上层抑制兴奋的远程区域从刺激位点，这表明在IC的兴奋性传播主要是由皮质局部电路介导的。AI/DI中兴奋性传播的这些特征，即沿着喙尾轴传播，而在腹背方向上传播较少，可能在将边缘结构产生的神经兴奋传递到额叶和眶皮质中起重要作用。(C)2010年IBRO。由爱思唯尔有限公司出版。保留所有权利。
The insular cortex (IC), composing unique anatomical connections, receives multi-modal sensory inputs including visceral, gustatory and somatosensory information from sensory thalamic nuclei. Axonal projections from the limbic structures, which have a profound influence on induction of epileptic activity, also converge onto the IC. However, functional connectivity underlying the physiological and pathological roles characteristic to the IC still remains unclear. The present study sought to elucidate the spatiotemporal dynamics of excitatory propagation and their cellular mechanisms in the IC using optical recording in urethane-anesthetized rats. Repetitive electrical stimulations of the IC at 50 Hz demonstrated characteristic patterns of excitatory propagation depending on the stimulation sites. Stimulation of the granular zone of the IC (GI) and other surrounding cortices such as the motor/primary sensory/secondary sensory cortices evoked round-shaped excitatory propagations, which often extended over the borders of adjacent areas, whereas excitation of the agranular and dysgranular zones in the IC (AI and DI, respectively) spread along the rostrocaudal axis parallel to the rhinal fissure. Stimulation of AI/DI often evoked excitation in the dorsolateral orbital cortex, which exhibited spatially discontinuous topography of excitatory propagation in the IC. Pharmacological manipulations using 6,7-dinitroquinoxaline-2,3(1H,4H)-dione (DNQX), a non-NMDA receptor antagonist, D-2-amino-5-phosphonovaleric acid (DAPV), an NMDA receptor antagonist, and bicuculline methiodide, a GAGA receptor antagonist, indicate that excitatory propagation was primarily regulated by non-NMDA and GABA receptors. Microinjection of lidocaine or incision of the supragranular layers of the rostrocaudally middle part of excitatory regions suppressed excitation in the remote regions from the stimulation site, suggesting that the excitatory propagation in the IC is largely mediated by cortical local circuits. These features of excitatory propagation in the AI/DI, that is the propagation along the rostrocaudal axis with less propagation in the ventro-dorsal direction, may play an important role for transmitting neural excitation arising from the limbic structures to the frontal and orbital cortices. (C) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.