Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae

PLoS One. 2015 Aug 7;10(8):e0135011. doi: 10.1371/journal.pone.0135011. eCollection 2015.

Abstract

Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS) that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM) ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ). Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC) only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Brain Mapping
  • Calcium / metabolism
  • Central Nervous System / physiology
  • Central Pattern Generators / physiology*
  • Coloring Agents / chemistry
  • Drosophila melanogaster / embryology*
  • Electrophysiology
  • Feeding Behavior*
  • Glutamine / chemistry
  • Green Fluorescent Proteins / metabolism
  • Immunohistochemistry
  • Larva / physiology
  • Light
  • Motor Neurons / metabolism*
  • Neurons / metabolism
  • Pharynx / innervation
  • Temperature

Substances

  • Coloring Agents
  • Glutamine
  • Green Fluorescent Proteins
  • Calcium

Grant support

This work was funded by the Deutsche Forschungsgemeinschaft (DFG) grant PA 787 and EXC 1023.