title: The sensory features of a food cue influence its ability to act as an incentive stimulus and evoke dopamine release in the nucleus accumbens core.
abstract: The sensory properties of a reward-paired cue (a conditioned stimulus; CS) may impact the motivational value attributed to the cue, and in turn influence the form of the conditioned response (CR) that develops. A cue with multiple sensory qualities, such as a moving lever-CS, may activate numerous neural pathways that process auditory and visual information, resulting in CRs that vary both within and between individuals. For example, CRs include approach to the lever-CS itself (rats that "sign-track"; ST), approach to the location of reward delivery (rats that "goal-track"; GT), or an "intermediate" combination of these behaviors. We found that the multimodal sensory features of the lever-CS were important to the development and expression of sign-tracking. When the lever-CS was covered, and thus could only be heard moving, STs not only continued to approach the lever location but also started to approach the food cup during the CS period. While still predictive of reward, the auditory component of the lever-CS was a much weaker conditioned reinforcer than the visible lever-CS. This plasticity in behavioral responding observed in STs closely resembled behaviors normally seen in rats classified as "intermediates." Furthermore, the ability of both the lever-CS and the reward-delivery to evoke dopamine release in the nucleus accumbens was also altered by covering the lever-dopamine signaling in STs resembled neurotransmission observed in rats that normally only GT. These data suggest that while the visible lever-CS was attractive, wanted, and had incentive value for STs, when presented in isolation, the auditory component of the cue was simply predictive of reward, lacking incentive salience. Therefore, the specific sensory features of cues may differentially contribute to responding and ensure behavioral flexibility.
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA bfsinger@umich.edu.
authors.forename: Bryan F
authors.identifier: 0000-0003-3474-6137
authors.initials: BF
authors.lastname: Singer
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Myranda A
authors.initials: MA
authors.lastname: Bryan
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Pavlo
authors.initials: P
authors.lastname: Popov
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Raymond
authors.initials: R
authors.lastname: Scarff
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Cody
authors.initials: C
authors.lastname: Carter
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Wright
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Aragona
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
mesh_terms: D000818:Animals; D001307:Auditory Perception / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D004298:Dopamine / Q000378:metabolism*; D004435:Eating / Q000502:physiology; D005502:Food; D008029:Lighting; D008297:Male; D009042:Motivation / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D009714:Nucleus Accumbens / Q000378:metabolism*; D011581:Psychological Tests; D017207:Rats, Sprague-Dawley; D012201:Reward; D014796:Visual Perception / Q000502:physiology
chemical_list: D004298:Dopamine