Tantot Frédéric, Parkes Shauna L, Marchand Alain R, Boitard Chloé, Naneix Fabien, Layé Sophie, Trifilieff Pierre, Coutureau Etienne, Ferreira Guillaume
INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France; Bordeaux University, Bordeaux, France.
INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France; Bordeaux University, Bordeaux, France; CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, Bordeaux, France.
Appetite. 2017 Jan 1;108:203-211. doi: 10.1016/j.appet.2016.10.001. Epub 2016 Oct 3.
Evidence now indicates that the chronic consumption of high-calorie foods, such as a high-fat diet (HFD), is associated with impaired control over food-seeking, yet the extent of this alteration is not fully understood. Using different reinforcement schedules, we evaluated whether HFD intake from weaning to adulthood modifies instrumental responding and induces a shift from goal-directed actions to habitual responding. We first observed reduced instrumental performance and motivation for a food reward in HFD-fed rats trained under schedules of reinforcement that facilitate habitual responding [Random Interval (RI)]. However, this deficit was alleviated if rats trained under RI were subsequently trained with reinforcement schedules that promote goal-directed strategies [Random Ratio (RR)]. Using an outcome devaluation procedure, we then demonstrated that consumption of a HFD promoted habitual behavior in rats trained under RI but not RR schedules. Finally, extended HFD exposure did not interfere with the ability of RR training to overcome impaired RI instrumental performance and to favor goal-directed behavior. These results indicate that chronic consumption of a HFD changes the co-ordination of goal-directed actions and habits and that alteration of food-seeking may be reversed under particular behavioral conditions.
目前有证据表明，长期食用高热量食物，如高脂饮食（HFD），与对觅食的控制受损有关，但这种改变的程度尚未完全了解。我们使用不同的强化程序，评估从断奶到成年期间摄入高脂饮食是否会改变工具性反应，并导致从目标导向行为转变为习惯性反应。我们首先观察到，在有助于形成习惯性反应的强化程序[随机间隔（RI）]下训练的高脂饮食喂养大鼠，其工具性表现和对食物奖励的动机降低。然而，如果在RI程序下训练的大鼠随后接受促进目标导向策略的强化程序[随机比率（RR）]训练，这种缺陷就会得到缓解。然后，我们使用结果贬值程序证明，高脂饮食的摄入促进了在RI程序而非RR程序下训练的大鼠的习惯性行为。最后，长期暴露于高脂饮食并未干扰RR训练克服受损的RI工具性表现并促进目标导向行为的能力。这些结果表明，长期食用高脂饮食会改变目标导向行为和习惯的协调，并且在特定行为条件下，觅食行为的改变可能会被逆转。
