Dopamine is required for learning and forgetting in Drosophila

Neuron. 2012 May 10;74(3):530-42. doi: 10.1016/j.neuron.2012.04.007.

Abstract

Psychological studies in humans and behavioral studies of model organisms suggest that forgetting is a common and biologically regulated process, but the molecular, cellular, and circuit mechanisms underlying forgetting are poorly understood. Here we show that the bidirectional modulation of a small subset of dopamine neurons (DANs) after olfactory learning regulates the rate of forgetting of both punishing (aversive) and rewarding (appetitive) memories. Two of these DANs, MP1 and MV1, exhibit synchronized ongoing activity in the mushroom body neuropil in alive and awake flies before and after learning, as revealed by functional cellular imaging. Furthermore, while the mushroom-body-expressed dDA1 dopamine receptor is essential for the acquisition of memory, we show that the dopamine receptor DAMB, also highly expressed in mushroom body neurons, is required for forgetting. We propose a dual role for dopamine: memory acquisition through dDA1 signaling and forgetting through DAMB signaling in the mushroom body neurons.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Analysis of Variance
  • Animals
  • Animals, Genetically Modified
  • Appetite / genetics
  • Avoidance Learning / physiology*
  • Behavior, Animal
  • Biophysics
  • Conditioning, Classical / physiology
  • Dopamine / metabolism*
  • Dopaminergic Neurons / physiology*
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Dynamins / genetics
  • Electroshock / adverse effects
  • Female
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Ion Channels
  • Male
  • Memory Disorders / genetics
  • Memory Disorders / physiopathology*
  • Models, Biological
  • Mushroom Bodies / cytology*
  • Mushroom Bodies / physiology
  • Odorants
  • Receptors, Dopamine D1 / metabolism
  • Repressor Proteins / genetics
  • Retention, Psychology / physiology
  • TRPA1 Cation Channel
  • TRPC Cation Channels / genetics
  • Temperature
  • Time Factors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Tyrosine 3-Monooxygenase / genetics

Substances

  • C15 protein, Drosophila
  • Drosophila Proteins
  • GAL4 protein, Drosophila
  • Ion Channels
  • Receptors, Dopamine D1
  • Repressor Proteins
  • TRPA1 Cation Channel
  • TRPC Cation Channels
  • Transcription Factors
  • TrpA1 protein, Drosophila
  • Green Fluorescent Proteins
  • Tyrosine 3-Monooxygenase
  • Dynamins
  • shi protein, Drosophila
  • Dopamine