title: Structural and Functional Plasticity within the Nucleus Accumbens and Prefrontal Cortex Associated with Time-Dependent Increases in Food Cue-Seeking Behavior.
abstract: Urges to consume food can be driven by stimuli in the environment that are associated with previous food experience. Identifying adaptations within brain reward circuits that facilitate cue-induced food seeking is critical for understanding and preventing the overconsumption of food and subsequent weight gain. Utilizing electrophysiological, biochemical, and DiI labeling, we examined functional and structural changes in the nucleus accumbens (NAc) and prefrontal cortex (PFC) associated with time-dependent increases in food craving ('incubation of craving'). Rats self-administered 60% high fat or chow 45 mg pellets and were then tested for incubation of craving either 1 or 30 days after training. High fat was chosen for comparison to determine whether palatability differentially affected incubation and/or plasticity. Rats showed robust incubation of craving for both food rewards, although responding for cues previously associated with high fat was greater than chow at both 1 and 30 days. In addition, previous experience with high-fat consumption reduced dendritic spine density in the PFC at both time points. In contrast, incubation was associated with an increase in NAc spine density and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated transmission at 30 days in both groups. Finally, incubation of craving for chow and high fat was accompanied by an increase in calcium-permeable and calcium-impermeable AMPARs, respectively. Our results suggest that incubation of food craving alters brain reward circuitry and macronutrient composition specifically induces cortical changes in a way that may facilitate maladaptive food-seeking behaviors.
authors.affiliation: Neuroscience Program, University of Wyoming, Laramie, WY, USA.
authors.forename: Paige M
authors.initials: PM
authors.lastname: Dingess
authors.affiliation: Neuroscience Program, University of Wyoming, Laramie, WY, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Darling
authors.affiliation: Neuroscience Program, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Rifka C
authors.initials: RC
authors.lastname: Derman
authors.affiliation: Department of Statistics, University of Wyoming, Laramie, WY, USA.
authors.forename: Shaun S
authors.initials: SS
authors.lastname: Wulff
authors.affiliation: School of Pharmacy, University of Wyoming, Laramie, WY, USA.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Hunter
authors.affiliation: Neuroscience Program, University of Michigan, Ann Arbor, MI, USA.|Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Carrie R
authors.initials: CR
authors.lastname: Ferrario
authors.affiliation: Neuroscience Program, University of Wyoming, Laramie, WY, USA.|Department of Statistics, University of Wyoming, Laramie, WY, USA.
authors.forename: Travis E
authors.initials: TE
authors.lastname: Brown
mesh_terms: D000818:Animals; D003463:Cues; D049229:Dendritic Spines / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D009714:Nucleus Accumbens / Q000166:cytology / Q000502:physiology*; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D012646:Self Administration; D013997:Time Factors