title: Drosophila learn opposing components of a compound food stimulus.
abstract: Dopaminergic neurons provide value signals in mammals and insects. During Drosophila olfactory learning, distinct subsets of dopaminergic neurons appear to assign either positive or negative value to odor representations in mushroom body neurons. However, it is not known how flies evaluate substances that have mixed valence. Here we show that flies form short-lived aversive olfactory memories when trained with odors and sugars that are contaminated with the common insect repellent DEET. This DEET-aversive learning required the MB-MP1 dopaminergic neurons that are also required for shock learning. Moreover, differential conditioning with DEET versus shock suggests that formation of these distinct aversive olfactory memories relies on a common negatively reinforcing dopaminergic mechanism. Surprisingly, as time passed after training, the behavior of DEET-sugar-trained flies reversed from conditioned odor avoidance into odor approach. In addition, flies that were compromised for reward learning exhibited a more robust and longer-lived aversive-DEET memory. These data demonstrate that flies independently process the DEET and sugar components to form parallel aversive and appetitive olfactory memories, with distinct kinetics, that compete to guide learned behavior.
authors.affiliation: Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Das
authors.affiliation: Laboratorio de Neurobiología de la Memoria, Facultad de Ciencias Exactas y Naturales, IFIBYNE-CONICET, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors.forename: Martín
authors.initials: M
authors.lastname: Klappenbach
authors.affiliation: Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Vrontou
authors.affiliation: Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Perisse
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Clark
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Burke
authors.affiliation: Centre for Neural Circuits and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK; Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA. Electronic address: scott.waddell@cncb.ox.ac.uk.
authors.forename: Scott
authors.initials: S
authors.lastname: Waddell
mesh_terms: D000818:Animals; D001070:Appetitive Behavior; D001362:Avoidance Learning; D002241:Carbohydrates / Q000502:physiology; D003214:Conditioning, Classical; D003671:DEET / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology*; D005260:Female; D007858:Learning; D008297:Male; D009812:Odorants; D055696:Olfactory Perception
chemical_list: D002241:Carbohydrates; D003671:DEET