A proprioceptive feedback circuit drives C. elegans locomotor adaptation through dopamine signaling

An animal adapts its motor behavior to navigate through the external environment. This adaptation depends on proprioception, which provides feedback on an animal’s body postures. How proprioception mechanisms interact with motor circuits and contribute to locomotor adaptation remains unclear. Here we describe and characterize proprioception-mediated homeostatic control of undulatory movement in the roundworm Caenorhabditis elegans. We found the worm responds to optogenetically or mechanically induced decreases in mid-body bending amplitude by increasing its anterior amplitude. Conversely, it responds to increased mid-body amplitude by decreasing the anterior amplitude. Using genetics, microfluidic and optogenetic perturbation response analyses, and optical neurophysiology, we elucidated the neural circuit underlying this compensatory postural response. The dopaminergic PDE neurons sense mid-body bending and signal to AVK interneurons via the D2-like dopamine receptor DOP-3. The FMRFamid..., (A) Folder 'Biomechanical experiments' contains original videos of locomotion of C. elegans in viscous fluids.  Worms were placed in chambers filled with dextran solutions.  Worm locomotion was collected by CCD camera mounted on a microscope.  Data were processed by customized behavioral analyzing code provided along.
The name of the each subfolder is in the format \"XXXX-XX-XX_XX_XXpct\", denoting the time, strain name, and viscosity of the medium. In each subfolder: 
(1) AVI files represent video recordings in both dark-field mode and binary mode. 
(2) MAT and TXT files represent intermediate data derived from the post-acquisition analysis of the video recordings; the post-acquisition analysis code is available from the referred article (link of the article is provided in this repository). Within the MAT and TXT file, the meaning of each variable is described in the data repository associated with the referred article.
 
(B) Folder 'Compensatory experiments' (part I to VI) contains orig..., ImageJ or other image/video softwares are required to open the image/video files. Intermediate files contained in the 'Optogenetic experiments' folder can be opened by MATLAB (2020b).