Nature ( IF 64.8 ) Pub Date : 2020-03-18 , DOI: 10.1038/s41586-020-2130-2 Oleg I Rumyantsev 1, 2, 3 , Jérôme A Lecoq 1, 2, 4, 5 , Oscar Hernandez 1, 2 , Yanping Zhang 1, 2, 6 , Joan Savall 1, 2, 6 , Radosław Chrapkiewicz 1, 2 , Jane Li 1, 4 , Hongkui Zeng 5 , Surya Ganguli 1, 3 , Mark J Schnitzer 1, 2, 3, 4, 6
How the brain processes information accurately despite stochastic neural activity is a longstanding question1. For instance, perception is fundamentally limited by the information that the brain can extract from the noisy dynamics of sensory neurons. Seminal experiments2,3 suggest that correlated noise in sensory cortical neural ensembles is what limits their coding accuracy4,5,6, although how correlated noise affects neural codes remains debated7,8,9,10,11. Recent theoretical work proposes that how a neural ensemble’s sensory tuning properties relate statistically to its correlated noise patterns is a greater determinant of coding accuracy than is absolute noise strength12,13,14. However, without simultaneous recordings from thousands of cortical neurons with shared sensory inputs, it is unknown whether correlated noise limits coding fidelity. Here we present a 16-beam, two-photon microscope to monitor activity across the mouse primary visual cortex, along with analyses to quantify the information conveyed by large neural ensembles. We found that, in the visual cortex, correlated noise constrained signalling for ensembles with 800–1,300 neurons. Several noise components of the ensemble dynamics grew proportionally to the ensemble size and the encoded visual signals, revealing the predicted information-limiting correlations12,13,14. Notably, visual signals were perpendicular to the largest noise mode, which therefore did not limit coding fidelity. The information-limiting noise modes were approximately ten times smaller and concordant with mouse visual acuity15. Therefore, cortical design principles appear to enhance coding accuracy by restricting around 90% of noise fluctuations to modes that do not limit signalling fidelity, whereas much weaker correlated noise modes inherently bound sensory discrimination.
中文翻译:
感觉皮层编码保真度的基本界限
尽管有随机的神经活动,大脑如何准确地处理信息是一个长期存在的问题1。例如,感知从根本上受到大脑可以从感觉神经元的嘈杂动态中提取的信息的限制。开创性实验2,3表明,感觉皮层神经集合中的相关噪声限制了它们的编码准确性4,5,6,尽管相关噪声如何影响神经代码仍有争议7,8,9,10,11。最近的理论工作提出,与绝对噪声强度相比,神经集合的感觉调谐特性如何与其相关噪声模式在统计上相关是编码准确性的更大决定因素12,13,14. 然而,如果没有来自数千个具有共享感觉输入的皮层神经元的同步记录,相关噪声是否会限制编码保真度是未知的。在这里,我们展示了一个 16 光束、双光子显微镜来监测小鼠初级视觉皮层的活动,以及对大型神经集合传递的信息进行量化的分析。我们发现,在视觉皮层中,具有 800-1,300 个神经元的集合的相关噪声约束信号。集合动态的几个噪声分量与集合大小和编码的视觉信号成比例增长,揭示了预测的信息限制相关性12,13,14. 值得注意的是,视觉信号垂直于最大噪声模式,因此不会限制编码保真度。信息限制噪声模式大约小十倍,并与鼠标视力15一致。因此,皮质设计原则似乎通过将大约 90% 的噪声波动限制在不限制信号保真度的模式来提高编码准确性,而更弱的相关噪声模式固有地限制了感官辨别。