Shosaku A
J Neurophysiol. 1986 May;55(5):1030-43. doi: 10.1152/jn.1986.55.5.1030.
Spontaneous activities of vibrissa-responding neurons in the rat ventrobasal complex (VB) and somatosensory part of the thalamic reticular nucleus (S-TR) were simultaneously recorded and subjected to cross-correlation analysis to investigate the functional organization of recurrent inhibitory action of the S-TR on VB neurons. Excitatory and/or inhibitory interactions were found between approximately 75% (25/34) of the pairs of S-TR and VB neurons with receptive fields (RFs) on the same vibrissa. In contrast, there was no significant interaction between 54 pairs of neurons having RFs on different vibrissae. Among the pairs of neurons with RFs on the same vibrissa, there were four types of correlations, which indicate the following connections: monosynaptic excitation from a VB to an S-TR neuron (7 pairs), monosynaptic inhibition from an S-TR to a VB neuron (10 pairs), reciprocal connection combining the above two types (7 pairs), and common excitation in addition to inhibition from an S-TR to a VB neuron (1 pair). Examples of divergence and convergence of connections between S-TR and VB neurons were demonstrated by testing one S-TR (VB) neuron with more than one VB (S-TR) neuron. Vibrissa-suppressed VB cells, which had exclusively inhibitory RFs, were included in eight pairs of the above samples. These VB cells were more likely to receive inhibitory inputs from S-TR neurons than other VB neurons. Cells with RFs on multiple vibrissae were included in the other 10 pairs. These multiple-vibrissa cells had no interaction with single-vibrissa cells but did with multiple-vibrissa cells. From the incidence of four types of correlation between S-TR and VB neurons with RFs on the same vibrissa, the following connection pattern is suggested: One S-TR neuron receives excitatory inputs from approximately 40% of the VB neurons with RFs on the same vibrissa and sends inhibitory outputs to approximately 55%. Since these two groups of VB neurons were overlapping, the S-TR neuron has reciprocal connections with approximately 20% of the VB neurons with RFs on the same vibrissa. The same estimate was applied to connectivity of one VB neuron. These results indicate that both inputs and outputs of S-TR neurons are precisely and topographically organized, although there is convergence to and divergence from a substantial number of VB neurons with RFs on the same vibrissa. It is proposed that the recurrent inhibitory circuit through the S-TR plays a role in improving discrimination of sensory information transmitted through the VB.
同时记录大鼠腹侧基底复合体（VB）和丘脑网状核体感部分（S-TR）中对触须有反应的神经元的自发活动，并进行互相关分析，以研究S-TR对VB神经元的反馈抑制作用的功能组织。在大约75%（25/34）的同一触须上具有感受野（RFs）的S-TR和VB神经元对之间发现了兴奋性和/或抑制性相互作用。相比之下，在54对不同触须上具有RFs的神经元之间没有显著的相互作用。在同一触须上具有RFs的神经元对中，有四种类型的相关性，表明以下连接方式：从VB到S-TR神经元的单突触兴奋（7对）、从S-TR到VB神经元的单突触抑制（10对）、结合上述两种类型的相互连接（7对）以及除了从S-TR到VB神经元的抑制之外的共同兴奋（1对）。通过用一个以上的VB（S-TR）神经元测试一个S-TR（VB）神经元，展示了S-TR和VB神经元之间连接的发散和会聚实例。上述样本中有8对包含了仅具有抑制性RFs的触须抑制性VB细胞。与其他VB神经元相比，这些VB细胞更有可能接受来自S-TR神经元的抑制性输入。其他10对包含了在多个触须上具有RFs的细胞。这些多触须细胞与单触须细胞没有相互作用，但与多触须细胞有相互作用。从同一触须上具有RFs的S-TR和VB神经元之间四种相关性的发生率来看，提出了以下连接模式：一个S-TR神经元从同一触须上大约40%的具有RFs的VB神经元接收兴奋性输入，并向大约55%的VB神经元发送抑制性输出。由于这两组VB神经元有重叠，S-TR神经元与同一触须上大约20%的具有RFs的VB神经元有相互连接。对一个VB神经元的连接性也应用了相同的估计。这些结果表明，尽管存在与同一触须上大量具有RFs的VB神经元的会聚和发散，但S-TR神经元的输入和输出都是精确且按拓扑方式组织的。有人提出，通过S-TR的反馈抑制回路在改善通过VB传递的感觉信息的辨别中起作用。
