Distinct dopamine neurons mediate reward signals for short- and long-term memories

Proc Natl Acad Sci U S A. 2015 Jan 13;112(2):578-83. doi: 10.1073/pnas.1421930112. Epub 2014 Dec 29.

Abstract

Drosophila melanogaster can acquire a stable appetitive olfactory memory when the presentation of a sugar reward and an odor are paired. However, the neuronal mechanisms by which a single training induces long-term memory are poorly understood. Here we show that two distinct subsets of dopamine neurons in the fly brain signal reward for short-term (STM) and long-term memories (LTM). One subset induces memory that decays within several hours, whereas the other induces memory that gradually develops after training. They convey reward signals to spatially segregated synaptic domains of the mushroom body (MB), a potential site for convergence. Furthermore, we identified a single type of dopamine neuron that conveys the reward signal to restricted subdomains of the mushroom body lobes and induces long-term memory. Constant appetitive memory retention after a single training session thus comprises two memory components triggered by distinct dopamine neurons.

Keywords: Drosophila; dopamine; learning and memory; mushroom body.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Appetitive Behavior / physiology
  • Carbohydrates
  • Dopaminergic Neurons / physiology*
  • Drosophila melanogaster / anatomy & histology
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / physiology*
  • Female
  • Learning / physiology
  • Memory, Long-Term / physiology
  • Memory, Short-Term / physiology
  • Mushroom Bodies / physiology
  • Odorants
  • Reward
  • Smell / physiology
  • Taste / physiology

Substances

  • Carbohydrates