Velica Anna, Henriksson Katharina, Malfatti Thawann, Ciralli Barbara, Nogueira Ingrid, Asimakidou Evridiki, Kullander Klas
Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
Eur J Neurosci. 2025 Apr;61(7):e70086. doi: 10.1111/ejn.70086.
The cortical somatostatin interneuron population includes several diverse cell types, among them the Martinotti cells. Layer-specific differences in connectivity and function between different subtypes of Martinotti cells are becoming apparent, which require contemporary studies to investigate cortical interneurons in a layer and subtype-specific manner. In this study, we investigate the connectivity of a subtype of Chrna2+ layer 5 Martinotti cells in the primary motor cortex, using a monosynaptic retrograde rabies viral tracer. We found direct input from pyramidal cells and local parvalbumin interneurons. In addition, we found long-range direct inputs from the motor thalamus, substantia innominata of the basal forebrain, and globus pallidus. Based on the observed input pattern, we tested and found an increased number of falls in the hanging wire test upon temporary overexcitation of Chrna2+ layer 5 Martinotti cells, suggesting that Chrna2+ Martinotti cells in the motor cortex can interfere with sensorimotor integration. In summary, our study provides novel insights into the connectivity and functional role of Mα2 cells in the M1 forelimb area, highlighting their unique integration of local and long-range inputs critical for sensorimotor processing, which lay the groundwork for further exploration of their role in cortical plasticity and motor learning.
皮质生长抑素中间神经元群体包括几种不同的细胞类型，其中有马丁诺蒂细胞。不同亚型的马丁诺蒂细胞在连接性和功能上的层特异性差异正变得明显，这需要当代研究以层和亚型特异性的方式来研究皮质中间神经元。在本研究中，我们使用单突触逆行狂犬病病毒示踪剂，研究了初级运动皮层中Chrna2⁺ 5层马丁诺蒂细胞亚型的连接性。我们发现了来自锥体细胞和局部小白蛋白中间神经元的直接输入。此外，我们还发现了来自运动丘脑、基底前脑无名质和苍白球的长程直接输入。基于观察到的输入模式，我们进行了测试，发现在暂时过度激活Chrna2⁺ 5层马丁诺蒂细胞后，悬线试验中的跌倒次数增加，这表明运动皮层中的Chrna2⁺ 马丁诺蒂细胞会干扰感觉运动整合。总之，我们的研究为M1前肢区域中Mα2细胞的连接性和功能作用提供了新的见解，突出了它们对局部和长程输入的独特整合，这对感觉运动处理至关重要，为进一步探索它们在皮质可塑性和运动学习中的作用奠定了基础。
