小柯机器人

美国洛克菲勒大学Gaby Maimon研究团队发现将非我目标转化为自我目标的转向信号。这一研究成果于2024年2月7日在线发表在国际学术期刊《自然》上。

研究人员描述了果蝇中枢复合体中神经元回路的表征，该回路比较内部产生的对果蝇航向和目标角度的估计，这两者都是以世界为中心（非我中心）的坐标编码，从而产生以身体为中心（自我中心）的转向信号。过去的研究表明，EPG神经元的活动代表了果蝇在导航过程中瞬间到瞬间的角度方向或航向角。然而，动物的瞬间航向角并不总是与其目标角一致，即其希望前进的非我方向。研究人员描述了果蝇大脑中的第二组神经元FC2细胞，它们的活动与果蝇的目标角相关。局部光遗传激活FC2神经元可诱导果蝇在向前行走时沿着实验者定义的方向定向。EPG和FC2神经元与第三类神经元PFL3细胞单突触连接。

研究人员发现，在目标定向导航过程中，单个PFL3细胞对航向角和目标角都表现出联合的脉冲率调谐。根据这三类细胞的解剖学和生理学原理，研究人员建立了一个模型，解释了这一回路如何比较方向角和目标角的非我中心，从而在PFL3输出端建立自我中心的转向信号。对PFL3活动的定量分析和光遗传操作支持了这一模型。

最后，研究人员利用一项新的导航记忆任务表明，在PFL3细胞亚集表达突触传递干扰物的果蝇沿着任意目标方向定向的能力下降，其效应大小与模型预测一致。研究人员所描述的生物回路揭示了大脑是如何比较两个群体水平的非我中心信号以产生适合运动控制的自我中心输出信号。

研究人员表示，与空间导航相关的神经元信号已在许多物种中得到描述。然而，对于这些信号如何相互作用以引导导航行为，还缺乏回路层面的了解。

附：英文原文

Title: Converting an allocentric goal into an egocentric steering signal

Author: Mussells Pires, Peter, Zhang, Lingwei, Parache, Victoria, Abbott, L. F., Maimon, Gaby

Issue&Volume: 2024-02-07

Abstract: Neuronal signals that are relevant for spatial navigation have been described in many species1,2,3,4,5,6,7,8,9,10. However, a circuit-level understanding of how such signals interact to guide navigational behaviour is lacking. Here we characterize a neuronal circuit in the Drosophila central complex that compares internally generated estimates of the heading and goal angles of the fly—both of which are encoded in world-centred (allocentric) coordinates—to generate a body-centred (egocentric) steering signal. Past work has suggested that the activity of EPG neurons represents the fly’s moment-to-moment angular orientation, or heading angle, during navigation2,11. An animal’s moment-to-moment heading angle, however, is not always aligned with its goal angle—that is, the allocentric direction in which it wishes to progress forward. We describe FC2 cells12, a second set of neurons in the Drosophila brain with activity that correlates with the fly’s goal angle. Focal optogenetic activation of FC2 neurons induces flies to orient along experimenter-defined directions as they walk forward. EPG and FC2 neurons connect monosynaptically to a third neuronal class, PFL3 cells12,13. We found that individual PFL3 cells show conjunctive, spike-rate tuning to both the heading angle and the goal angle during goal-directed navigation. Informed by the anatomy and physiology of these three cell classes, we develop a model that explains how this circuit compares allocentric heading and goal angles to build an egocentric steering signal in the PFL3 output terminals. Quantitative analyses and optogenetic manipulations of PFL3 activity support the model. Finally, using a new navigational memory task, we show that flies expressing disruptors of synaptic transmission in subsets of PFL3 cells have a reduced ability to orient along arbitrary goal directions, with an effect size in quantitative accordance with the prediction of our model. The biological circuit described here reveals how two population-level allocentric signals are compared in the brain to produce an egocentric output signal that is appropriate for motor control.

DOI: 10.1038/s41586-023-07006-3

Source: https://www.nature.com/articles/s41586-023-07006-3

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/
投稿链接：http://www.nature.com/authors/submit_manuscript.html