title: Inadequate early social experience increases the incentive salience of reward-related cues in adulthood.
abstract: The mechanisms by which childhood abuse and/or neglect become risk factors for the development of drug addiction, problem gambling, and other disorders of behavioral inhibition are unknown. The loss of behavioral inhibition is often triggered by reward-related cues that acquire incentive salience. This study examined whether inadequate early-life social experience in rats affects the incentive salience of reward-related cues. Rats were deprived of early-life social experience with the mother and litter through artificial-rearing (AR). A group of AR rats (AR+STM) received additional tactile stimulation that mimicked maternal licking, a critical component of rat maternal care. Control rats were maternally reared (MR). The incentive salience attributed to a food cue was measured in adult rats using a conditioned approach task, where a conditional stimulus (CS; lever) was paired with food delivery, and in a conditional reinforcement task. The dependent measures were approach towards the CS (sign-tracking) versus approach towards the place of food delivery (goal-tracking) and instrumental responding for the CS. AR rats made significantly more sign-tracking responses than MR rats. AR rats also made more instrumental responses when reinforced with the CS. AR+STM rats' responses were intermediate to MR and AR rats. Thus, inadequate early-life social experience enhanced the incentive salience of a reward-related cue in adulthood. Replacement of maternal licking partially reversed this effect. These results highlight a potential link between early-life social adversity and susceptibility to disorders of behavioral inhibition.
authors.affiliation: Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Rd N., Mississauga, ON L5L 1C6, Canada.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Lomanowska
authors.forename: Vedran
authors.initials: V
authors.lastname: Lovic
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rankine
authors.forename: Skyler J
authors.initials: SJ
authors.lastname: Mooney
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
authors.forename: Gary W
authors.initials: GW
authors.lastname: Kraemer
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D008297:Male; D009042:Motivation / Q000502:physiology*; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D012201:Reward; D012919:Social Behavior