小柯机器人

美国哥伦比亚大学Franck Polleux研究小组近日取得一项新成果。经过不懈努力，他们发现一种人类特有的皮质连接和电路功能修饰因子。这一研究成果发表在2021年10月27日出版的国际学术期刊《自然》上。
 
研究人员发现由SRGAP2C表达诱导的第2/3层锥体神经元(PN)接收兴奋性突触数量增加源于局部和远程皮质-皮质特定连接的增加。在所有皮质PN中表达人源化SRGAP2C的小鼠显示出感觉刺激激活的第2/3层PN分数变化，以及学习依赖皮质感觉辨别任务能力增强。计算模型显示，由SRGAP2C表达引起的第4层到第2/3层连接性增加解释了感官编码特性的一些关键变化。这些结果表明，在人类进化过程中，SRGAP2C的出现有助于人类皮层中皮层回路的特定结构和功能特征的进化。

据介绍，普遍认为人大脑皮层电路结构的独特特征可以表征人类的认知能力，该特征结构包括皮层-皮层连接增多。然而，尚不清楚这些连接变化的进化起源以及它们如何影响皮层回路功能和行为。在大脑大小增加主要阶段之前，人类特异性基因SRGAP2C复制就已在人类祖先的基因组中出现。小鼠中SRGAP2C表达增加了第2/3层PN接收的兴奋性和抑制性突触密度。

附：英文原文

Title: A human-specific modifier of cortical connectivity and circuit function

Author: Schmidt, Ewoud R. E., Zhao, Hanzhi T., Park, Jung M., Dipoppa, Mario, Monsalve-Mercado, Mauro M., Dahan, Jacob B., Rodgers, Chris C., Lejeune, Amlie, Hillman, Elizabeth M. C., Miller, Kenneth D., Bruno, Randy M., Polleux, Franck

Issue&Volume: 2021-10-27

Abstract: The cognitive abilities that characterize humans are thought to emerge from unique features of the cortical circuit architecture of the human brain, which include increased cortico–cortical connectivity. However, the evolutionary origin of these changes in connectivity and how they affected cortical circuit function and behaviour are currently unknown. The human-specific gene duplication SRGAP2C emerged in the ancestral genome of the Homo lineage before the major phase of increase in brain size1,2. SRGAP2C expression in mice increases the density of excitatory and inhibitory synapses received by layer 2/3 pyramidal neurons (PNs)3,4,5. Here we show that the increased number of excitatory synapses received by layer 2/3 PNs induced by SRGAP2C expression originates from a specific increase in local and long-range cortico–cortical connections. Mice humanized for SRGAP2C expression in all cortical PNs displayed a shift in the fraction of layer 2/3 PNs activated by sensory stimulation and an enhanced ability to learn a cortex-dependent sensory-discrimination task. Computational modelling revealed that the increased layer 4 to layer 2/3 connectivity induced by SRGAP2C expression explains some of the key changes in sensory coding properties. These results suggest that the emergence of SRGAP2C at the birth of the Homo lineage contributed to the evolution of specific structural and functional features of cortical circuits in the human cortex.

DOI: 10.1038/s41586-021-04039-4

Source: https://www.nature.com/articles/s41586-021-04039-4

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
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