ELECTROPHYSIOLOGY OF NEURONS OF LATERAL THALAMIC NUCLEI IN CAT - RESTING PROPERTIES AND BURST DISCHARGES
ELECTROPHYSIOLOGY OF NEURONS OF LATERAL THALAMIC NUCLEI IN CAT - RESTING PROPERTIES AND BURST DISCHARGES
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DOI：
10.1152/jn.1984.51.6.1196
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
STERIADE, M
中科院分区：
文献类型：
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作者：
DESCHENES, M;PARADIS, M;STERIADE, M
在巴比妥钠麻醉下，对猫丘脑外侧核(腹前-腹外侧核、腹后外侧核、中央外侧核和网状核)进行细胞内和细胞外记录。通过刺激皮质投射区和丘脑前部传入通路，神经元被逆行和/或突触驱动。根据电生理和解剖学标准，确定了三类神经元：丘脑中继神经元、局部中间神经元和丘脑网状神经元。静息状态下，丘脑神经元出现两种共存节律。膜电位在8~12赫兹出现短周期振荡(S 1~2次)，周期为.apprx。S。在中继神经元中，每一波都以一系列超极化和爆发放电为特征。这些每10个S重复出现的节律性超极化事件可被超极化电流或注入氯离子逆转，从而提示它们主要由节律性抑制性突触后电位组成。慢的0.1赫兹节律是由其他神经元池施加给中继神经元的。在皮质和高位脑干病变完全隔离丘脑后，仍然存在缓慢的0.1赫兹节律。这种节律是由抑制因子在丘脑内产生的。在丘脑中间神经元(按电生理标准鉴定)，重复去极化(8~12 Hz)和爆发放电的短暂发作(1~2次S)每10个S重复一次。在此期间，中间神经元的膜电位缓慢超极化，与中继性神经元的节律性相位超极化形成对比。大多数中继神经元共有的电生理特性包括持续时间较长的后峰超极化电位，这种电位可被钙离子螯合剂阻断；在棘波触发水平附近有起搏电位；在爆发放电背后有低阈值的体细胞钙电导。一般说来，丘脑前叶激发的兴奋性突触后电位较皮层激发的EPSP升高更快，持续时间更短。此外，丘脑前部传入诱发反应可能与快速前电位的产生有关，其中一些似乎是树突棘波的结果。丘脑神经元的突触和固有膜特性允许它们在两种模式下工作：一种是中继模式，一种是振荡模式；振荡模式是丘脑固有的，而中继模式是由皮质和脑干结构指挥和维持的。
Intracellular and extracellular recordings were performed in lateral thalamic nuclei (ventroanterior-ventrolateral, ventropostero-lateral, centralis lateralis and reticularis) of cats under barbiturate anesthesia. Neurons were driven antidromically and/or synaptically by stimulating cortical projection areas and prethalamic afferent pathways. Three neuronal populations were identified on the basis of electrophysiological and anatomical criteria: thalamic relay neurons, local interneurons, and reticularis thalami neurons. At rest, 2 coexistent rhythms were observed in thalamic neurons. Brief episodes (1-2 s) of membrane-potential oscillations at frequencies of 8-12 Hz appeared with a periodicity of .apprx. 10 s. In relay neurons, each episode was characterized by a sequence of hyperpolarizations and burst discharges. These rhythmic episodes of hyperpolarization recurring about every 10 s could be reversed in sign by hyperpolarizing currents or by Cl injection, hence suggesting that they were mainly composed of rhythmic inhibitory postsynaptic potentials (IPSP). The slow 0.1-Hz rhythm was imposed on relay neurons by other neuronal pools. Following a complete isolation of the thalamus by cortical and high brain stem lesions, the slow 0.1-Hz rhythm was still present. This rhythm was generated within the thalamus by inhibitory elements. In thalamic interneurons (identified by electrophysiological criteria) brief episodes (1-2 s) of repetitive depolarizations (8-12 Hz) and burst discharges recurred every 10 s. In the interval, the membrane potential of interneurons slowly hyperpolarized, contrasting with the rhythmic phasic hyperpolarizations observed in relay neurons. Electrophysiological properties shared by most relay neurons included afterspike hyperpolarizing potentials of long duration, which were blocked by injections of a Ca chelator; a pacemaker potential in the vicinity of the spike trigger level and a low-threshold somatic Ca conductance that underlies burst discharges. As a general rule, prethalamic volleys induced faster rising and shorter lasting EPSP [excitatory postsynaptic potentials] than cortical volleys. Moreover, prethalamic afferent-evoked responses could be associated with production of fast prepotentials, some of which appeared to result from dendritic spiking. Synaptic and intrinsic membrane properties of thalamic neurons allow them to function under 2 modes: a relay mode and an oscillatory mode; the oscillatory mode being intrinsic to the thalamus and the relay mode being commanded and maintained by cortical and brain stem structures.