AUTHOR=Kosheleff Alisa R. , Araki Jingwen , Tsan Linda , Chen Grace , Murphy Niall P. , Maidment Nigel T. , Ostlund Sean B. TITLE=Junk Food Exposure Disrupts Selection of Food-Seeking Actions in Rats JOURNAL=Frontiers in Psychiatry VOLUME=9 YEAR=2018 URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2018.00350 DOI=10.3389/fpsyt.2018.00350 ISSN=1664-0640 ABSTRACT=

There is growing evidence that repeated consumption of highly palatable, nutritionally poor “junk food” diets can produce deficits in cognition and behavioral control. We explored whether long-term junk-food diet exposure disrupts rats' ability to make adaptive choices about which foods to pursue based on (1) expected reward value (outcome devaluation test) and (2) cue-evoked reward expectations (Pavlovian-to-instrumental test). Rats were initially food restricted and trained on two distinct response-outcome contingencies (e.g., left press chocolate pellets, and right press sweetened condensed milk) and stimulus-outcome contingencies (e.g., white noise chocolate pellets, and clicker sweetened condensed milk). They were then given 6 weeks of unrestricted access to regular chow alone (controls) or chow and either 1 or 24 h access to junk food per day. Subsequent tests of decision making revealed that rats in both junk-food diet groups were impaired in selecting actions based on either expected food value or the presence of food-paired cues. These data demonstrate that chronic junk food consumption can disrupt the processes underlying adaptive control over food-seeking behavior. We suggest that the resulting dysregulation of food seeking may contribute to overeating and obesity.