Evaluating proteins for simultaneous calcium imaging and optogenetics in C. elegans with microfluidic devices

To study causal links between neurons, or between neurons and behavior, it is desirable to be able to optogenetically activate neurons while recording calcium activity (ideally pan-neuronally) along with behavior. However, there are several issues lying within the combination of these techniques, such as the overlapping spectra of calcium indicator excitation and opsin activation. Here, I report progress developing calcium imaging and optogenetics tools that enable precise monitoring and manipulating neural activity in the nematode Caenorhabditis elegans. Genetically engineered worms expressing GECIs, jGCaMP7s, jRGECO1a, and RGECO1.2, and channelrhodopsin variants, Chrimson and ReaChR, were generated and tested. I also fabricated microfluidic chips for immobilizing and stimulating worms while monitoring their neural activity. I hope these new strains combined with our microfluidics setup will facilitate systematic studies of neural circuits in worms.--Author's abstract