title: High-sucrose diets in male rats disrupt aspects of decision making tasks, motivation and spatial memory, but not impulsivity measured by operant delay-discounting.
abstract: Excessive consumption of sugar sweetened drinks is proposed to produce functional changes in the hippocampus and prefrontal cortex, leading to perturbations in behavioural control. Impairments in behavioural control have been observed in obese people on tasks that involve making choices, including delay-discounting, indicative of increased impulsivity. In this study we examined the impact of 2h daily access to 10% sucrose (or no sucrose in controls) in young male rats on behavioural tasks reliant on hippocampal function including delay-discounting, T-maze forced choice alternation and place recognition memory, as well as progressive ratio to measure motivation. We observed deficits in place recognition memory and T-maze forced choice alternation, indicative of hippocampal deficits in rats with a history of sucrose consumption. Moreover, rats with a history of sucrose consumption were less motivated to lever press for rewards on a progressive ratio schedule. However, rats with a history of sucrose consumption performed equally to control animals during the delay-discounting task, suggesting that they discounted for reward size over a delay in a manner comparable to control animals. These findings indicate that high-sucrose diets impact on spatial and working memory processes, but do not induce impulsive-like choice behaviours in rats, suggesting that unhealthy diet choices may not influence this aspect of decision-making behaviour.
authors.affiliation: School of Psychology, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Alanna
authors.initials: A
authors.lastname: Wong
authors.affiliation: School of Psychology, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Vimi R
authors.initials: VR
authors.lastname: Dogra
authors.affiliation: School of Psychology, UNSW Australia, Sydney, NSW 2052, Australia; School of Health and Biomedical Sciences, RMIT University, VIC 3083, Australia. Electronic address: amy.reichelt@rmit.edu.au.
authors.forename: Amy C
authors.initials: AC
authors.lastname: Reichelt
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight; D003216:Conditioning, Operant; D065786:Delay Discounting; D004032:Diet / Q000009:adverse effects*; D019422:Dietary Sucrose / Q000009:adverse effects*; D007175:Impulsive Behavior; D008297:Male; D018782:Maze Learning; D008570:Memory, Short-Term; D009042:Motivation; D011581:Psychological Tests; D017207:Rats, Sprague-Dawley; D021641:Recognition, Psychology; D065852:Spatial Memory
chemical_list: D019422:Dietary Sucrose
keywords: Decision making; Delay discounting; Diet; High sucrose diet; Hippocampus; Impulsivity; Instrumental conditioning; Motivation; Prefrontal cortex; Spatial memory; T maze; Working memory