当前位置:科学网首页 > 小柯机器人 >详情
感觉皮层编码保真度的界限
作者:小柯机器人 发布时间:2020/3/24 13:11:46

感觉皮层编码保真度的基本界限,这一成果由美国斯坦福大学Mark J. Schnitzer、Surya Ganguli和Oleg I. Rumyantsev研究组经过不懈努力而取得。相关论文于2020年3月18日在线发表在《自然》杂志上。

在该研究中,研究人员利用一个16束双光子显微镜,以监测整个小鼠初级视觉皮层的活动,并进行分析以量化由大型神经团传递的信息。研究发现,在视觉皮层中与800-1300个神经元集合相关的噪声限制了信号传递。整体动力的许多噪声分量与整体大小和编码的视觉信号成比例地增长,这揭示了预测信息的限制相关性。特别是视觉信号与最大噪声模式正交,因此不限制编码保真度。信息限制噪声模式约小十倍,并与小鼠的视敏度一致。因此,皮质设计原理似乎通过将约90%的噪声波动限制为不限制信号保真度的模式来增强编码准确性,而较弱的相关噪声模式限制了感觉辨别力。

据了解,尽管存在随机的神经活动,但大脑如何准确地处理信息是一个长期存在的问题。例如,知觉从根本上受到大脑从感觉神经元嘈杂动态中提取信息的限制。先前实验表明感觉皮质神经团中相关噪声是限制其编码准确性的因素,尽管这些噪声如何影响神经编码仍有争议。最近的理论工作提出,与绝对噪声强度相比,神经团的感觉调节特性如何与其相关噪声模式在统计上的关联是编码精度的更大决定因素。但是,如果没有来自数千个具有共享感觉输入皮质神经元的同步记录,则未知相关噪声是否会限制编码保真度。

附:英文原文

Title: Fundamental bounds on the fidelity of sensory cortical coding

Author: Oleg I. Rumyantsev, Jrme A. Lecoq, Oscar Hernandez, Yanping Zhang, Joan Savall, Radosaw Chrapkiewicz, Jane Li, Hongkui Zeng, Surya Ganguli, Mark J. Schnitzer

Issue&Volume: 2020-03-18

Abstract: 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.

DOI: 10.1038/s41586-020-2130-2

Source: https://www.nature.com/articles/s41586-020-2130-2

期刊信息

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:43.07
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html