TY - JOUR TI - Flexible motor sequence generation during stereotyped escape responses AU - Wang, Yuan AU - Zhang, Xiaoqian AU - Xin, Qi AU - Hung, Wesley AU - Florman, Jeremy AU - Huo, Jing AU - Xu, Tianqi AU - Xie, Yu AU - Alkema, Mark J AU - Zhen, Mei AU - Wen, Quan A2 - Zimmer, Manuel A2 - Sengupta, Piali VL - 9 PY - 2020 DA - 2020/06/05 SP - e56942 C1 - eLife 2020;9:e56942 DO - 10.7554/eLife.56942 UR - https://doi.org/10.7554/eLife.56942 AB - Complex animal behaviors arise from a flexible combination of stereotyped motor primitives. Here we use the escape responses of the nematode Caenorhabditis elegans to study how a nervous system dynamically explores the action space. The initiation of the escape responses is predictable: the animal moves away from a potential threat, a mechanical or thermal stimulus. But the motor sequence and the timing that follow are variable. We report that a feedforward excitation between neurons encoding distinct motor states underlies robust motor sequence generation, while mutual inhibition between these neurons controls the flexibility of timing in a motor sequence. Electrical synapses contribute to feedforward coupling whereas glutamatergic synapses contribute to inhibition. We conclude that C. elegans generates robust and flexible motor sequences by combining an excitatory coupling and a winner-take-all operation via mutual inhibition between motor modules. KW - motor sequence generation KW - feedforward excitation KW - winner-take-all KW - escape response KW - mutual inhibition JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -