Central processing of leg proprioception in Drosophila: Physiology and behavior data

Proprioception, the sense of self-movement and position, is mediated by mechanosensory neurons that detect diverse features of body kinematics. Although proprioceptive feedback is crucial for accurate motor control, little is known about how downstream circuits transform limb sensory information to guide motor output. Here, we investigate neural circuits in Drosophila that process proprioceptive information from the fly leg. We identify three cell-types from distinct developmental lineages that are positioned to receive input from proprioceptor subtypes encoding tibia position, movement, and vibration. 13Bα neurons encode femur-tibia joint angle and mediate postural changes in tibia position. 9Aα neurons also drive changes in leg posture, but encode a combination of directional movement, high-frequency vibration, and joint angle. Activating 10Bα neurons, which encode tibia vibration at specific joint angles, elicits pausing in walking flies. Altogether, our results reveal that central circuits integrate information across proprioceptor subtypes to construct complex sensorimotor representations that mediate diverse behaviors, including reflexive control of limb posture and detection of leg vibration.

Methods
See manuscript (https://doi.org/10.7554/eLife.60299) for details.

本体感觉（Proprioception）是感知机体自身运动与空间位置的感官功能，由能够检测身体运动学多样特征的机械感觉神经元所介导。尽管本体感觉反馈对精准运动控制至关重要，但目前对于下游神经环路如何转化肢体感觉信息以指导运动输出的机制仍知之甚少。本研究聚焦果蝇（Drosophila）体内处理腿部本体感觉信息的神经环路，鉴定出三种来自不同发育谱系的细胞类型，这些细胞的分布位置使其能够接收编码胫骨位置、运动及振动的本体感受器亚型的输入信号。其中13Bα神经元可编码股胫关节角度，并介导胫骨位置相关的姿势改变；9Aα神经元同样可驱动腿部姿势变化，但它编码的是定向运动、高频振动与关节角度的组合信息；激活10Bα神经元（该类神经元可编码特定关节角度下的胫骨振动信号）会引发行走果蝇的暂停行为。综上，本研究结果揭示中枢神经环路可整合不同本体感受器亚型的信息，从而构建复杂的感觉运动表征，介导包括肢体姿势反射控制与腿部振动检测在内的多种行为。
Methods
详细实验方法参见本研究手稿（https://doi.org/10.7554/eLife.60299）