Three dopamine pathways induce aversive odor memories with different stability

PLoS Genet. 2012;8(7):e1002768. doi: 10.1371/journal.pgen.1002768. Epub 2012 Jul 12.

Abstract

Animals acquire predictive values of sensory stimuli through reinforcement. In the brain of Drosophila melanogaster, activation of two types of dopamine neurons in the PAM and PPL1 clusters has been shown to induce aversive odor memory. Here, we identified the third cell type and characterized aversive memories induced by these dopamine neurons. These three dopamine pathways all project to the mushroom body but terminate in the spatially segregated subdomains. To understand the functional difference of these dopamine pathways in electric shock reinforcement, we blocked each one of them during memory acquisition. We found that all three pathways partially contribute to electric shock memory. Notably, the memories mediated by these neurons differed in temporal stability. Furthermore, combinatorial activation of two of these pathways revealed significant interaction of individual memory components rather than their simple summation. These results cast light on a cellular mechanism by which a noxious event induces different dopamine signals to a single brain structure to synthesize an aversive memory.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dopamine* / genetics
  • Dopamine* / metabolism
  • Dopamine* / physiology
  • Dopaminergic Neurons / metabolism
  • Dopaminergic Neurons / physiology
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila Proteins / physiology
  • Drosophila melanogaster* / genetics
  • Drosophila melanogaster* / physiology
  • Electric Stimulation
  • Ion Channels
  • Memory / physiology*
  • Mushroom Bodies* / metabolism
  • Mushroom Bodies* / physiology
  • Odorants*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • TRPA1 Cation Channel
  • TRPC Cation Channels / genetics
  • TRPC Cation Channels / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology

Substances

  • Drosophila Proteins
  • GAL4 protein, Drosophila
  • Ion Channels
  • TRPA1 Cation Channel
  • TRPC Cation Channels
  • Transcription Factors
  • TrpA1 protein, Drosophila
  • ppl protein, Drosophila
  • Dopamine