Comprehensive analysis of behavioral dynamics in the protochordate Ciona intestinalis

Abstract

Vertebrate nervous systems can generate a remarkable diversity of behaviors. However, our understanding of how behaviors may have evolved in the chordate lineage is limited by the lack of neuroethological studies leveraging our closest invertebrate relatives. Here we combine high-throughput video acquisition with pharmacological perturbations of bioamine signaling to systematically reveal the global structure of the motor behavioral repertoire in the Ciona intestinalis larvae. Most of Cionas postural variance can be captured by six basic shapes, which we term "Eigencionas". Motif analysis of postural time series further demonstrated that bioamines influence numerous stereotyped behavioral maneuvers including "startle-like" and "beat-and-glide". Employing computational modeling of swimming dynamics and spatio-temporal embedding of postural features revealed that subtle behavioural differences are generated at the levels of motor modules and the transitions between, both modulated by bioamines. Finally, we show that flexible motor module usage gives rise to diverse behaviors in response to different light stimuli.