西亚试剂：Neural dynamics for landmark orientation and angular path i

Many animals navigate using a combination of visual landmarks and path integration. In mammalian brains, head direction cells integrate these two streams of information by representing an animal's heading relative to landmarks, yet maintaining their directional tuning in darkness based on self-motion cues. Here we use two-photon calcium imaging in head-fixed Drosophila melanogasterwalking on a ball in a virtual reality arena to demonstrate that landmark-based orientation and angular path integration are combined in the population responses of neurons whose dendrites tile the ellipsoid body, a toroidal structure in the centre of the fly brain. The neural population encodes the fly's azimuth relative to its environment, tracking visual landmarks when available and relying on self-motion cues in darkness. When both visual and self-motion cues are absent, a representation of the animal's orientation is maintained in this network through persistent activity, a potential substrate for short-term memory. Several features of the population dynamics of these neurons and their circular anatomical arrangement are suggestive of ring attractors, network structures that have been proposed to support the function of navigational brain circuits.

昆虫的脑在导航过程中是怎样将视觉标志与路径整合相结合的一直不清楚。Johannes Seelig 和Vivek Jayarama对在一个虚拟现实台上行走的被绑住的果蝇的大脑进行了钙成像研究，发现“铺”在“椭球体”(ellipsoid body)上的一组带树突的神经元能够利用来自视觉标志和果蝇自身转动的信息来计算前进方向。这是关于已知对哺乳动物大脑的空间导航有贡献的“前进方向”(head direction)神经元的无脊椎动物对应物的第一个证据。

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