title: Individual variation in the propensity to attribute incentive salience to a food cue: influence of sex.
abstract: There is considerable individual variation in the propensity of animals to attribute incentive salience to discrete reward cues, but to date most of this research has been conducted in male rats. The purpose of this study was to determine whether sex influences the propensity to attribute incentive salience to a food cue, using rats from two different outbred strains (Sprague-Dawley [SD] and Heterogeneous Stock [HS]). The motivational value of a food cue was assessed in two ways: (i) by the ability of the cue to elicit approach toward it and (ii) by its ability to act as a conditioned reinforcer. We found that female SD rats acquired Pavlovian conditioned approach behavior slightly faster than males, but no sex difference was detected in HS rats, and neither strain showed a sex difference in asymptotic performance of approach behavior. Moreover, female approach behavior did not differ across estrous cycle. Compared to males, females made more active responses during the test for conditioned reinforcement, although they made more inactive responses as well. We conclude that although there are small sex differences in performance on these tasks, these are probably not due to a notable sex difference in the propensity to attribute incentive salience to a food cue.
authors.affiliation: Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Kyle K
authors.initials: KK
authors.lastname: Pitchers
authors.affiliation: Department of Psychology, University of Michigan, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Shelly B
authors.initials: SB
authors.lastname: Flagel
authors.affiliation: Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: O'Donnell
authors.affiliation: Department of Pediatrics, Human and Molecular Genetics Center and Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Leah C Solberg
authors.initials: LC
authors.lastname: Woods
authors.affiliation: Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Sarter
authors.affiliation: Department of Psychology, University of Michigan, Ann Arbor, MI, USA. Electronic address: ter@umich.edu.
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
mesh_terms: D000818:Animals; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D005260:Female; D005502:Food; D007206:Individuality; D008297:Male; D009042:Motivation / Q000235:genetics / Q000502:physiology*; D025341:Principal Component Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012727:Sex Characteristics
keywords: Conditioned reinforcement; Goal-tracker; Pavlovian conditioned approach; Sex differences; Sign-tracker