Hilscher Markus M, Leão Richardson N, Edwards Steven J, Leão Katarina E, Kullander Klas
Unit of Developmental Genetics, Department of Neuroscience, Uppsala University, Uppsala, Sweden.
Brain Institute, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.
PLoS Biol. 2017 Feb 9;15(2):e2001392. doi: 10.1371/journal.pbio.2001392. eCollection 2017 Feb.
Martinotti cells are the most prominent distal dendrite-targeting interneurons in the cortex, but their role in controlling pyramidal cell (PC) activity is largely unknown. Here, we show that the nicotinic acetylcholine receptor α2 subunit (Chrna2) specifically marks layer 5 (L5) Martinotti cells projecting to layer 1. Furthermore, we confirm that Chrna2-expressing Martinotti cells selectively target L5 thick-tufted type A PCs but not thin-tufted type B PCs. Using optogenetic activation and inhibition, we demonstrate how Chrna2-Martinotti cells robustly reset and synchronize type A PCs via slow rhythmic burst activity and rebound excitation. Moreover, using optical feedback inhibition, in which PC spikes controlled the firing of surrounding Chrna2-Martinotti cells, we found that neighboring PC spike trains became synchronized by Martinotti cell inhibition. Together, our results show that L5 Martinotti cells participate in defined cortical circuits and can synchronize PCs in a frequency-dependent manner. These findings suggest that Martinotti cells are pivotal for coordinated PC activity, which is involved in cortical information processing and cognitive control.
马丁诺蒂细胞是皮质中最突出的靶向远端树突的中间神经元，但其在控制锥体细胞（PC）活动中的作用在很大程度上尚不清楚。在这里，我们表明烟碱型乙酰胆碱受体α2亚基（Chrna2）特异性标记投射到第1层的第5层（L5）马丁诺蒂细胞。此外，我们证实表达Chrna2的马丁诺蒂细胞选择性靶向L5厚簇状A型PC，而不是细簇状B型PC。使用光遗传学激活和抑制，我们展示了Chrna2-马丁诺蒂细胞如何通过缓慢的节律性爆发活动和反弹兴奋有力地重置和同步A型PC。此外，使用光反馈抑制，其中PC尖峰控制周围Chrna2-马丁诺蒂细胞的放电，我们发现相邻的PC尖峰序列通过马丁诺蒂细胞抑制而同步。总之，我们的结果表明L5马丁诺蒂细胞参与特定的皮质回路，并能以频率依赖的方式同步PC。这些发现表明马丁诺蒂细胞对于协调PC活动至关重要，而PC活动参与皮质信息处理和认知控制。
