Highly Differentiated Projection-Specific Cortical Subnetworks
Highly Differentiated Projection-Specific Cortical Subnetworks
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DOI：
10.1523/jneurosci.0772-11.2011
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发表时间：
2011-07-13
影响因子：
5.3
通讯作者：
Kawaguchi, Yasuo
中科院分区：
文献类型：
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作者：
Morishima, Mieko;Morita, Kenji;Kawaguchi, Yasuo
新皮层的锥体细胞根据其皮层外投射目标可分化为几个亚群。然而，对于这些特定输出通道的锥体神经元的相对皮质内连通性知之甚少。通过配对记录和定量形态学分析，揭示了大鼠额叶皮层第5层（L5）两组不同的锥体细胞在不同的丘脑输入过程中不同的突触传递特性、连接模式和形态学分化。逆行示踪剂用于标记L5的两种投影亚型：向纹状体两侧突出的交叉皮质纹状体（CCS）细胞和向同侧脑桥突出的皮质孔体（CPn）细胞。虽然CPn/CPn和CCS/CCS对具有相似的连接概率，但CPn/CPn对表现出更强的互反连通性、更强的幺正突触传递和更容易的成对脉冲响应。这些突触特征与突触前神经元的投射亚型密切相关。CPn和CCS细胞根据它们的体细胞位置（L5a和L5b，后者是更密集的丘脑传入纤维）和它们的树突/轴突分支进一步分化。总之，我们的数据表明，锥体投射系统根据皮层下目标和丘脑输入被划分为不同的输出通道，这些通道内部和之间的信息流是有选择性地组织起来的。
Pyramidal cells in the neocortex are differentiated into several subgroups based on their extracortical projection targets. However, little is known regarding the relative intracortical connectivity of pyramidal neurons specialized for these specific output channels. We used paired recordings and quantitative morphological analysis to reveal distinct synaptic transmission properties, connection patterns, and morphological differentiation correlated with heterogeneous thalamic input to two different groups of pyramidal cells residing in layer 5 (L5) of rat frontal cortex. Retrograde tracers were used to label two projection subtypes in L5: crossed-corticostriatal (CCS) cells projecting to both sides of the striatum, and corticopontine (CPn) cells projecting to the ipsilateral pons. Although CPn/CPn and CCS/CCS pairs had similar connection probabilities, CPn/CPn pairs exhibited greater reciprocal connectivity, stronger unitary synaptic transmission, and more facilitation of paired-pulse responses. These synaptic characteristics were strongly correlated to the projection subtype of the presynaptic neuron. CPn and CCS cells were further differentiated according to their somatic position (L5a and L5b, the latter denser thalamic afferent fibers) and their dendritic/axonal arborizations. Together, our data demonstrate that the pyramidal projection system is segregated into different output channels according to subcortical target and thalamic input, and that information flow within and between these channels is selectively organized.