Affective Pavlovian motivation is enhanced in obesity susceptible populations; implications for incentive motivation in obesity

Abstract

Global obesity rates continue to rise, presenting a major challenge to human health. Efforts to uncover the drivers of this epidemic have highlighted the contribution of Pavlovian motivational processes to overeating. In humans, brain and behavioral reactivity to food related stimuli positively correlates with subsequent weight gain. In concordance with this, selectively bred obesity-prone rats exhibit stronger cue-triggered food-seeking via single outcome Pavlovian-to-instrumental transfer (SO PIT) than obesity-resistant rats. These data show that Pavlovian motivation is stronger in selectively bred obesity-prone groups. However, whether obesity susceptibility in outbred populations is associated with enhanced PIT is unknown. Moreover, PIT can arise via two neurobehaviorally dissociable processes, a sensory specific versus a general affective process that cannot be distinguished by SO PIT. Thus, it is unclear which PIT process is enhanced in obesity-prone groups. Therefore, we determined whether obesity susceptibility in outbred populations is associated with enhanced Sensory Specific (SS) PIT or General PIT and whether expression of these forms of PIT differs between selectively bred obesity-prone versus obesity-resistant rats. We find that in outbred rats, the magnitude of General PIT is positively correlated with subsequently determined obesity susceptibility. In selectively bred rats, the magnitude of General PIT was stronger in obesity-prone versus obesity-resistant groups. Jointly, these data show that enhanced affective Pavlovian motivation is tightly linked to obesity vulnerability, supporting a role for phenotypic differences in incentive motivation for the development of obesity. This has important implications for obesity prevention and for understanding the neurocircuitry mediating enhanced food-seeking in vulnerable individuals.