To do this, we examined transgenic animals in which either the A- or B-type cholinergic motor neurons are specifically deactivated by an active K+ channel (Punc-4::twk-18(gf)-UrSL-wCherry and Pacr-5::twk-18(gf)-UrSL-wCherry, respectively) ( Kawano et al., 2011; Kunkel et al., 2000), as well as unc-25 mutants that lack the GABA neurotransmitter required by the D-type motor neurons ( Jin et al., 1999). During forward locomotion, the bending waves of animals propagated from head to tail when either the A-or D-type motor neurons were inactivated ( Figures S4A and S4C). When trapping the worm in the pneumatic microfluidic device, the posterior region of these worms followed the induced body www.selleckchem.com/GSK-3.html bending

toward either side ( Figures S4B and S4D). In contrast, inactivating the B-type motor neurons prevented an induced bend from anterior regions from propagating to posterior regions ( Figures 6D–6F; Movie S9). When the B-type motor neurons were inactivated, the curvature of the posterior region was not locked to the curvature Selleckchem GSI-IX of the trapped region ( Figures 6D and 6E) as for wild-type worms

( Figures 4A and 4B). The C. elegans motor circuit does not possess local sensory or interneurons that convey local bending information to B-type motor neurons. The DVA interneuron, whose axon spans the whole worm body and connects with most DB motor neurons, has been shown to have proprioceptive properties ( Hu et al., 2011; Li et al., 2006). We thus asked whether DVA plays a role in propagating local bending information during forward locomotion. However, we found that laser killing DVA does not disrupt the ability of the

posterior region to follow the curvature of the anterior region ( Figures S4G and S4H). Taken together, these results show that neither the A- and D-type motor neurons nor the DVA interneuron are needed to propagate the bending signal from anterior to posterior regions. However, the B-type motor neurons are essential. We also asked whether second the body muscle cells themselves might propagate bending signals from anterior to posterior regions. Adjacent body wall muscle cells are connected by gap junctions mediated specifically by an innexin UNC-9, providing a possible alternative pathway for transducing the proprioceptive signal (Figure 1B) (Liu et al., 2006). First, we trapped transgenic worms expressing halorhodopsin in their muscle cells (Pmyo-3::NpHR) in the pneumatic channel. We found that specifically relaxing the muscles in the trapped curved region with green light illumination had no effect on the curvature of the free posterior region ( Figures S4E and S4F). We also tested transgenic animals that lacked these gap junctions in their muscle cells. To do this, we used a transgenic unc-9 mutant animal in which unc-9 expression was restored in UNC-9-expressing cells except the body wall muscles.