Specialized Cortical Subnetworks Differentially Connect Frontal Cortex to Parahippocampal Areas
Specialized Cortical Subnetworks Differentially Connect Frontal Cortex to Parahippocampal Areas
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DOI：
10.1523/jneurosci.2810-11.2012
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发表时间：
2012-02-01
影响因子：
5.3
通讯作者：
Kawaguchi, Yasuo
中科院分区：
文献类型：
--
作者：
Hirai, Yasuharu;Morishima, Mieko;Kawaguchi, Yasuo
信息是如何在额叶皮质的局部回路中被操纵和分离的仍然是个谜，部分原因是对不同锥体细胞亚型的连接知之甚少。额叶皮质通过投射到周围皮质参与陈述性记忆的形成和提取，并通过投射到纹状体/桥核参与程序性学习。在大鼠额叶皮质，我们发现了两种锥体细胞亚型，它们选择性地投射到大鼠额周围皮质(PRC)的不同亚区。额叶皮质上2/3层(L2/3)的PRC投射细胞投射到周围区35，而L5的神经元投射到周围区36。L2/3PRC投射细胞与投射到杏仁基底外侧核的细胞部分重叠。L5PRC投射细胞与交叉的皮质纹状体细胞部分重叠，但与邻近的皮质丘脑/桥脑皮质细胞不同。L5PRC投射细胞和Cth细胞在电生理特性和树突/轴突形态上有所不同。在额叶皮质内，L2/3 PRC投射细胞以相似的概率支配L5 PRC投射细胞和Cth细胞，但只接受PRC投射细胞的反馈兴奋。这些数据表明，不同皮质层中的特定神经元亚型是通过层间环相互兴奋的。因此，两个相互作用的输出通道将信息从额叶皮质发送到海马旁网络的不同层次阶段，区域35和36，另外的侧支分别选择性地以杏仁核或基底节为靶点。结合PRC投射细胞和Cth细胞的分层连接，这些观察结果显示了额叶投射神经元的精细多样化，根据它们参与不同的记忆子系统而选择性地连接。
How information is manipulated and segregated within local circuits in the frontal cortex remains mysterious, in part because of inadequate knowledge regarding the connectivity of diverse pyramidal cell subtypes. The frontal cortex participates in the formation and retrieval of declarative memories through projections to the perirhinal cortex, and in procedural learning through projections to the striatum/pontine nuclei. In rat frontal cortex, we identified two pyramidal cell subtypes selectively projecting to distinct subregions of perirhinal cortex (PRC). PRC-projecting cells in upper layer 2/3 (L2/3) of the frontal cortex projected to perirhinal area 35, while neurons in L5 innervated perirhinal area 36. L2/3 PRC-projecting cells partially overlapped with those projecting to the basolateral amygdala. L5 PRC-projecting cells partially overlapped with crossed corticostriatal cells, but were distinct from neighboring corticothalamic (CTh)/corticopontine cells. L5 PRC-projecting and CTh cells were different in their electrophysiological properties and dendritic/axonal morphologies. Within the frontal cortex, L2/3 PRC-projecting cells innervated L5 PRC-projecting and CTh cells with similar probabilities, but received feedback excitation only from PRC-projecting cells. These data suggest that specific neuron subtypes in different cortical layers are reciprocally excited via interlaminar loops. Thus, two interacting output channels send information from the frontal cortex to different hierarchical stages of the parahippocampal network, areas 35 and 36, with additional collaterals selectively targeting the amygdala or basal ganglia, respectively. Combined with the hierarchical connectivity of PRC-projecting and CTh cells, these observations demonstrate an exquisite diversification of frontal projection neurons selectively connected according to their participation in distinct memory subsystems.