小柯机器人

近日，英国伦敦大学学院Michael Häusser等研究人员合作发现，皮质-皮质反馈吸引视觉皮层中的活跃树突。相关论文于2023年5月3日在线发表在《自然》杂志上。

研究人员用小鼠的长距离全光连接图表明，从后内侧高级视觉区（LM）到初级视觉皮层（V1）的反馈影响在空间上是有组织的。当反馈的来源和目标代表视觉空间的同一区域时，反馈是相对抑制的。相反，当反馈源在视觉空间中与目标偏离时，反馈就会相对促进。双光子钙成像数据显示，这种促进性反馈在V1锥体神经元的顶端簇状树突中是非线性整合的：视网膜偏移（环绕）的视觉刺激驱动局部树突钙信号，指示再生事件，双光子光遗传学激活投射到V1中确定的反馈接受刺的LM神经元，可以驱动类似的分支特定的局部钙信号。这些研究结果表明，新皮层的反馈连接和非线性树突整合可以共同形成一个基质，从而支持预测性和合作性的环境互动。

据悉，新皮层的感觉处理需要皮层区域之间的前馈和反馈信息流。在反馈处理中，高层次的表征为低层次的表征提供背景信息，并促进知觉功能，如围道积分和图地分割。然而，人们对介导反馈影响的回路和细胞机制了解有限。

附：英文原文

Title: Cortico-cortical feedback engages active dendrites in visual cortex

Author: Fiek, Mehmet, Herrmann, Dustin, Egea-Weiss, Alexander, Cloves, Matilda, Bauer, Lisa, Lee, Tai-Ying, Russell, Lloyd E., Husser, Michael

Issue&Volume: 2023-05-03

Abstract: Sensory processing in the neocortex requires both feedforward and feedback information flow between cortical areas1. In feedback processing, higher-level representations provide contextual information to lower levels, and facilitate perceptual functions such as contour integration and figure–ground segmentation2,3. However, we have limited understanding of the circuit and cellular mechanisms that mediate feedback influence. Here we use long-range all-optical connectivity mapping in mice to show that feedback influence from the lateromedial higher visual area (LM) to the primary visual cortex (V1) is spatially organized. When the source and target of feedback represent the same area of visual space, feedback is relatively suppressive. By contrast, when the source is offset from the target in visual space, feedback is relatively facilitating. Two-photon calcium imaging data show that this facilitating feedback is nonlinearly integrated in the apical tuft dendrites of V1 pyramidal neurons: retinotopically offset (surround) visual stimuli drive local dendritic calcium signals indicative of regenerative events, and two-photon optogenetic activation of LM neurons projecting to identified feedback-recipient spines in V1 can drive similar branch-specific local calcium signals. Our results show how neocortical feedback connectivity and nonlinear dendritic integration can together form a substrate to support both predictive and cooperative contextual interactions.

DOI: 10.1038/s41586-023-06007-6

Source: https://www.nature.com/articles/s41586-023-06007-6

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
官方网址：http://www.nature.com/
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