title: Serotonin promotes exploitation in complex environments by accelerating decision-making.
abstract: BACKGROUND
  Fast responses can provide a competitive advantage when resources are inhomogeneously distributed. The nematode Caenorhabditis elegans was shown to modulate locomotion on a lawn of bacterial food in serotonin (5-HT)-dependent manners. However, potential roles for serotonergic signaling in responding to food discovery are poorly understood.
  
  
  RESULTS
  We found that 5-HT signaling in C. elegans facilitates efficient exploitation in complex environments by mediating a rapid response upon encountering food. Genetic or cellular manipulations leading to deficient serotonergic signaling resulted in gradual responses and defective exploitation of a patchy foraging landscape. Physiological imaging revealed that the NSM serotonergic neurons responded acutely upon encounter with newly discovered food and were key to rapid responses. In contrast, the onset of responses of ADF serotonergic neurons preceded the physical encounter with the food. The serotonin-gated chloride channel MOD-1 and the ortholog of mammalian 5-HT1 metabotropic serotonin receptors SER-4 acted in synergy to accelerate decision-making. The relevance of responding rapidly was demonstrated in patchy environments, where the absence of 5-HT signaling was detrimental to exploitation.
  
  
  CONCLUSIONS
  Our results implicate 5-HT in a novel form of decision-making, demonstrate its fitness consequences, suggest that NSM and ADF act in concert to modulate locomotion in complex environments, and identify the synergistic action of a channel and a metabotropic receptor in accelerating C. elegans decision-making.
authors: The Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA.
authors: Shachar
authors: S
authors: Iwanir
authors: Committee on Computational Neuroscience, The University of Chicago, Chicago, IL, 60637, USA.
authors: Adam S
authors: AS
authors: Brown
authors: The Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA.
authors: Stanislav
authors: S
authors: Nagy
authors: Department of Physics and the James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA.
authors: Dana
authors: D
authors: Najjar
authors: Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors: Alexander
authors: A
authors: Kazakov
authors: Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA, 02138, USA.
authors: Kyung Suk
authors: KS
authors: Lee
authors: Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
authors: Alon
authors: A
authors: Zaslaver
authors: Department of Physics and Center for Systems Biology, Harvard University, Cambridge, MA, 02138, USA.
authors: Erel
authors: E
authors: Levine
authors: The Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA. david.biron@gmail.com.|Department of Physics and the James Franck Institute, The University of Chicago, Chicago, IL, 60637, USA. david.biron@gmail.com.
authors: David
authors: D
authors: Biron
mesh_terms: D000818:Animals; D001070:Appetitive Behavior; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D004777:Environment; D008124:Locomotion; D012701:Serotonin / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D029742:Caenorhabditis elegans Proteins; D012701:Serotonin