Connection analysis of corticostriatal cells

为了揭示产生皮层输出到纹状体的皮层内回路，我们鉴定了额叶皮层中含有许多皮质纹状体细胞的神经元类型，并定量分析了它们的形态和突触连接。纹状体锥体细胞的形态和生理鉴定。通过荧光逆行标记，我们发现投射到脑桥核的锥体细胞[皮质纹状体（CPn）细胞]和对侧纹状体[交叉皮质纹状体（CCS）细胞]是不同的群体，并且在初始阶段响应去极化的双重放电仅在CPn细胞中发现。CPn细胞的根尖簇比CCS细胞的根尖簇发育得更多，但根尖簇的结构在CCS细胞中是不同的，这取决于体细胞的位置。目的鉴定非锥体细胞亚型及其形态定量分析。我们定量地鉴定了非锥体细胞亚型，并分析了它们的轴突分支和突触钮扣的形成以及树突分支和棘的分布。分支间和突触钮扣距离是独立确定的，每个亚型都有这些手段的独特组合。根据初生树突数量、树突延伸方向、平均枝长和棘密度将非锥体细胞划分为3种树突类型。棘密度以Martinotti细胞最高。不同亚型间形态棘型的组成也存在差异。已鉴定的锥体和非锥体细胞亚型之间的突触连接。我们利用体外切片制备的成对记录和细胞内染色细胞的形态学重建来研究上述细胞之间的突触连接模式。比较了快速尖峰细胞和CCS细胞之间的突触电流。电流振幅依赖于兴奋性连接的接触位点数量，但强烈依赖于抑制性连接的接触位点。少

To reveal the intracortical circuitry of generating cortical outputs to the striatum, we identified neuron types in the frontal cortex with many corticostriatal cells, and analyzed their morphologies and synaptic connections quantitatively.1.Morphological and physiological identification of pyramidal cells projecting the striatum.By fluorescent retrograde labeling we found that pyramidal cells projecting to the pontine nuclei [corticopontine (CPn) cells] and the contralateral striatum [crossed corticostriatal (CCS) cells] were separate populations, and that doublet firing at the initial phase in response to depolarization was found only in CPn cells. The apical tufts developed more in CPn cells than CCS cells, but the tuft structures were variable among CCS cells, dependent on the soma location.2.Objective identification of nonpyramidal cell subtypes and quantitative analysis of their morphologies.We identified nonpyramidal cells subtypes quantitatively from the firing and axonal arbor … More izing patterns, and analyzed their axonal branching and synaptic bouton formation as well as the dendritic branching and spine distribution quantitatively. The inter-branch and synaptic bouton distances were determined independently, and each subtypes had a unique combination of these means. Nonpyramidal cells were divided into three dendritic patterns by the primary dendrite number issuing from a soma, their extending direction, mean branch length and spine density. The spine density was highest in Martinotti cells. Composition of morphological spine types was also different among subtypes.3.Synaptic connections among identified pyramidal and nonpyramidal cell subtypes.We investigated the synaptic connections patterns among cells identified as above, using paired recording in vitro slice preparation and morphological reconstruction of intracellular stained cells. The synaptic currents from fast-spiking or CCS cells to CCS cells were compared. The current amplitude was dependent on the number of contact sites in excitatory connections, but strongly dependent on the contact locations in inhibitory connections. Less