Olfactory associative learning in Caenorhabditis elegans is impaired in lrn-1 and lrn-2 mutants

Behav Neurosci. 1999 Apr;113(2):358-67. doi: 10.1037//0735-7044.113.2.358.


The C. elegans mutants, lrn-1 and lrn-2, are impaired in associative learning using conditioned taste cues. Both mutants are defective in associative learning about appetitive and aversive events, indicating that lrn-1 and lrn-2 exert effects across motivational boundaries. In a new olfactory associative learning paradigm, in which wild type worms learn to avoid a previously attractive diacetyl odor after it has been paired with an aversive acetic acid solution, lrn-1 and lrn-2 are impaired. Although defective in associative learning using a conditioned olfactory cue, nonassociative learning (habituation and dishabituation) using this same olfactory cue is unaffected. The discovery that lrn-1 and lrn-2 are defective in associative learning with both taste and olfactory cues may suggest that associative learning in different sensory modalities converges on a common genetic pathway in C. elegans that is subserved by lrn-1 and lrn-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Association Learning / physiology*
  • Caenorhabditis elegans / genetics*
  • Chemotaxis
  • Conditioning, Classical
  • Extinction, Psychological
  • Habituation, Psychophysiologic
  • Mutation / genetics*
  • Olfactory Receptor Neurons / physiology*