A single neuron in C. elegans orchestrates multiple motor outputs through parallel modes of transmission

Animals generate a wide range of highly coordinated motor outputs, which allows them to execute purposeful behaviors. Individual neurons in the circuits that generate behaviors have a remarkable capacity for flexibility, as they exhibit multiple axonal projections, transmitter systems, and modes of neural activity. How these multi-functional properties of neurons enable the generation of adaptive behaviors remains unknown. Here we show that the HSN neuron in C. elegans evokes multiple motor programs over different timescales to enable a suite of behavioral changes during egg-laying. Using HSN activity perturbations and in vivo calcium imaging, we show that HSN acutely increases egg-laying and locomotion while also biasing the animals towards low-speed dwelling behavior over minutes. The acute effects of HSN on egg-laying and high-speed locomotion are mediated by separate sets of HSN transmitters and different HSN axonal projections. The long-lasting effects on dwelling are mediated by HSN release of serotonin that is taken up and re-released by NSM, another serotonergic neuron class that directly evokes dwelling. Our results show how the multi-functional properties of a single neuron allow it to induce a coordinated suite of behaviors and also reveal that neurons can borrow serotonin from one another to control behavior.ImageJ tracking script: Put the .txt file and the .ijm file in the same folder under the "macros" folder in ImageJ/Fiji installation. The .txt file includes settings that can be adjusted for the neuron of interest. the .ijm file is an ImageJ macro Neuron retracking script: MATLAB code that enables tracking of fluorescence intensity in the same neuron location in different channel. The inputs required are a txt file containing the neuron location (which is the output of the ImageJ tracking script), and Tiff files from the recordings. For HSN GCaMP dataset: there are 6 file folders: 1) gcamp raw 2) mscarlet raw 3) Ratiometric are in .mat files (MATLAB) ; 4) Eggevetns 5) GcampPeaks and 6) speed are in txt file format For BAG GCaMP dataset: each folder contains a JPEG file to define fused agar boundary and a gcamp tracking file (a csv with: frame,xcoord,ycoored,intdens,intsub,bgmedian,maxint,area,x,y,sqintdens,sqintsub,sqarea,threshold,animal,redFlag,useTracking)Funding provided by: National Institutes of HealthCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000002Award Number: NS124338Funding provided by: National Institutes of HealthCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000002Award Number: GM135413Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: 1845663Funding provided by: McKnight FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100005270Award Number: Funding provided by: Alfred P. Sloan FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000879Award Number: Funding provided by: JPB FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100007457Award Number:GCaMP datasets were collected from freely-moving C. elegans animals, using widefield imaging of animals on agar slides, as described in the manuscript