Anatomical and electrophysiological mechanisms for asymmetrical excitatory propagation in the rat insular cortex: In vivo optical imaging and whole-cell patch-clamp studies
Anatomical and electrophysiological mechanisms for asymmetrical excitatory propagation in the rat insular cortex: In vivo optical imaging and whole-cell patch-clamp studies
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DOI：
10.1002/cne.23246
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发表时间：
2013-05-01
影响因子：
2.5
通讯作者：
Kobayashi, Masayuki
中科院分区：
文献类型：
--
作者：
Adachi, Kazunori;Fujita, Satoshi;Kobayashi, Masayuki
岛叶皮质（IC）将来自杏仁核和下丘脑核的边缘系统信息与包括内脏、味觉和躯体感觉信息在内的多模式感觉输入进行整合。然而，岛叶皮质兴奋的功能框架仍然未知。我们在氨基甲酸乙酯麻醉的大鼠中使用全细胞膜片钳技术进行光学成像和单个锥体神经元染色，以阐明岛叶皮质锥体神经元精确的解剖学和生理学特征，这些神经元通过其水平连接调节皮质信息处理。光学成像显示，对颗粒状岛叶皮质（GI）或无颗粒岛叶皮质（DI）进行电刺激会引发沿与嗅沟平行的头尾轴的特征性兴奋传播，且偏向头侧方向。无颗粒岛叶皮质/颗粒状岛叶皮质中第II/III层锥体细胞的树突和轴突的空间模式支持这些兴奋的功能特征；例如，头尾向的轴突分支往往以偏向头侧的方向延伸。从胞体到头侧最远部位的轴突平均长度比尾侧长度大约长50%。无颗粒岛叶皮质/颗粒状岛叶皮质中的锥体细胞在“向上”和“向下”状态下表现出自发的膜振荡。与光学成像获得的诱发信号类似，对距离记录细胞约1毫米的尾侧岛叶皮质进行重复电刺激（50赫兹下5个脉冲）在“向下”状态下诱导诱发兴奋性突触后电位的叠加，在“向上”状态下诱导显著的抑制性突触后电位。对兴奋特征及其细胞基础的阐明为岛叶皮质中神经活动不对称传播的功能机制提供了新的线索。《比较神经学杂志》2013年521卷：1598 - 1613页。（c）2012威利期刊公司
The insular cortex (IC) integrates limbic information from the amygdala and hypothalamic nucleus to multimodal sensory inputs, including visceral, gustatory, and somatosensory information. However, the functional framework of excitation in the IC is still unknown. We performed optical imaging and single pyramidal neuronal staining using a whole-cell patch-clamp technique in urethane-anesthetized rats to elucidate the precise anatomical and physiological features of IC pyramidal neurons, which regulate cortical information processing via their horizontal connections. Optical imaging revealed that electrical stimulation of the granular (GI) or dysgranular (DI) IC elicited characteristic excitatory propagations along the rostrocaudal axis parallel to the rhinal fissure, with a preference toward the rostral direction. Spatial patterns of the dendrites and axons of layer II/III pyramidal cells in the DI/GI support these functional features of excitation; for example, rostrocaudal axonal arbors tend to extend with a rostral directional preference. The mean length of the axons from the soma to the farthest site rostrally was approximate to 50% longer than that of the caudal length. Pyramidal cells in the DI/GI exhibited spontaneous membrane oscillation in the UP and DOWN states. Similarly to the evoked signals obtained by optical imaging, repetitive electrical stimulation of the caudal IC approximate to 1 mm away from the recorded cells (five pulses at 50 Hz) induced the summation of evoked excitatory postsynaptic potentials during the DOWN state and profound inhibitory postsynaptic potentials during the UP state. Clarification of the excitation feature with its cellular basis provides new clues about the functional mechanisms of the asymmetric propagation of neural activities in the IC. J. Comp. Neurol. 521:15981613, 2013. (c) 2012 Wiley Periodicals, Inc.