title: Dopamine levels modulate the updating of tastant values.
abstract: To survive, animals must constantly update the internal value of stimuli they encounter; a process referred to as incentive learning. Although there have been many studies investigating whether dopamine is necessary for reward, or for the association between stimuli and actions with rewards, less is known about the role of dopamine in the updating of the internal value of stimuli per se. We used a single-bottle forced-choice task to investigate the role of dopamine in learning the value of tastants. We show that dopamine transporter knock-out mice (DAT-KO), which have constitutively elevated dopamine levels, develop a more positive bias towards a hedonically positive tastant (sucrose 400 mM) than their wild-type littermates. Furthermore, when compared to wild-type littermates, DAT-KO mice develop a less negative bias towards a hedonically negative tastant (quinine HCl 10 mM). Importantly, these effects develop with training, because at the onset of training DAT-KO and wild-type mice display similar biases towards sucrose and quinine. These data suggest that dopamine levels can modulate the updating of tastant values, a finding with implications for understanding sensory-specific motivation and reward seeking.
authors.affiliation: Department of Neurobiology and Center of Neuroengineering, Duke University Medical Center, Durham, NC, USA. costarui@mail.nih.gov
authors.forename: R M
authors.initials: RM
authors.lastname: Costa
authors.forename: R
authors.initials: R
authors.lastname: Gutierrez
authors.forename: I E
authors.initials: IE
authors.lastname: de Araujo
authors.forename: M R P
authors.initials: MR
authors.lastname: Coelho
authors.forename: A D
authors.initials: AD
authors.lastname: Kloth
authors.forename: R R
authors.initials: RR
authors.lastname: Gainetdinov
authors.forename: M G
authors.initials: MG
authors.lastname: Caron
authors.forename: M A L
authors.initials: MA
authors.lastname: Nicolelis
authors.forename: S A
authors.initials: SA
authors.lastname: Simon
mesh_terms: D000818:Animals; D001245:Association Learning / Q000502:physiology; D002755:Choice Behavior / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000502:physiology*; D005518:Food Preferences / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009042:Motivation; D013649:Taste / Q000235:genetics / Q000502:physiology*
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D004298:Dopamine