Neural and genetic degeneracy underlies Caenorhabditis elegans feeding behavior

Nicholas F. Trojanowski, Olivia Padovan-Merhar, David M. Raizen, Christopher Fang-Yen

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Degenerate networks, in which structurally distinct elements can perform the same function or yield the same output, are ubiquitous in biology. Degeneracy contributes to the robustness and adaptability of networks in varied environmental and evolutionary contexts. However, how degenerate neural networks regulate behavior in vivo is poorly understood, especially at the genetic level. Here, we identify degenerate neural and genetic mechanisms that underlie excitation of the pharynx (feeding organ) in the nematode Caenorhabditis elegans using cell-specific optogenetic excitation and inhibition. We show that the pharyngeal neurons MC, M2, M4, and I1 form multiple direct and indirect excitatory pathways in a robust network for control of pharyngeal pumping. I1 excites pumping via MC and M2 in a state-dependent manner. We identify nicotinic and muscarinic receptors through which the pharyngeal network regulates feeding rate. These results identify two different mechanisms by which degeneracy is manifest in a neural circuit in vivo.

Original languageEnglish
Pages (from-to)951-961
Number of pages11
JournalJournal of Neurophysiology
Issue number4
Publication statusPublished - 2014 Aug 15


  • Behavior
  • Feeding
  • Neural circuits
  • Optogenetics

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology


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