Data from: 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
FMRFamide-like neuropeptide FLP-1, released by AVK, regulates SMB head
motor neurons to modulate anterior bending. We propose that this
homeostatic behavioral control optimizes the efficiency of locomotion. Our
findings demonstrate a mechanism in which proprioception works with
dopamine and neuropeptide signaling to mediate motor control, a motif that
may be conserved in other animals.