Ciliomotor circuitry underlying whole-body coordination of ciliary activity in the Platynereis larva

Elife. 2017 May 16;6:e26000. doi: 10.7554/eLife.26000.


Ciliated surfaces harbouring synchronously beating cilia can generate fluid flow or drive locomotion. In ciliary swimmers, ciliary beating, arrests, and changes in beat frequency are often coordinated across extended or discontinuous surfaces. To understand how such coordination is achieved, we studied the ciliated larvae of Platynereis dumerilii, a marine annelid. Platynereis larvae have segmental multiciliated cells that regularly display spontaneous coordinated ciliary arrests. We used whole-body connectomics, activity imaging, transgenesis, and neuron ablation to characterize the ciliomotor circuitry. We identified cholinergic, serotonergic, and catecholaminergic ciliomotor neurons. The synchronous rhythmic activation of cholinergic cells drives the coordinated arrests of all cilia. The serotonergic cells are active when cilia are beating. Serotonin inhibits the cholinergic rhythm, and increases ciliary beat frequency. Based on their connectivity and alternating activity, the catecholaminergic cells may generate the rhythm. The ciliomotor circuitry thus constitutes a stop-and-go pacemaker system for the whole-body coordination of ciliary locomotion.

Keywords: P. dumerilii; acetylcholine; catecholamines; ciliary nerve; connectomics; neuroscience; serotonin; zooplankton.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aquatic Organisms / genetics
  • Aquatic Organisms / physiology
  • Cholinergic Neurons / physiology
  • Cilia / physiology*
  • Connectome
  • Gene Transfer Techniques
  • Larva / genetics
  • Larva / physiology
  • Locomotion
  • Motion
  • Optical Imaging
  • Polychaeta / genetics
  • Polychaeta / physiology*
  • Serotonergic Neurons / physiology

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.