Cognitive load reduces the reinforcement of ventral striatum by anterior insula in taste processing: An fMRI study on self-control

Recent studies have shown that cognitive overload disrupted the affective processing of taste attributes in foodrelated tasks, which is difficult to explain using dual-system theories with their reflective and impulsive systems (involved in the cognitive and affective processing of stimuli, respectively). The tripartite neurocognitive model proposes an additional interoceptive system that regulates the activities of reflective and impulsive systems. Using this framework, we studied self-control over food choices and hypothesized inferior processing of both affective (taste) and cognitive (health) components of choice-relevant attributes under increased cognitive load. We expected increased cognitive load to decrease the coupling between interoceptive and impulsive systems (represented by anterior insula (AI) and ventral striatum (VS), respectively), and to strengthen decoupling between interoceptive and reflective system (represented by dorsolateral prefrontal cortex (DLPFC)). In an fMRI scanner, 49 participants made 60 food choices requiring self-control (i.e., between a healthier and tastier item) twice: in high (HL) and low working memory load (LL) conditions. We found that functional connectivity between the right AI and VS was weaker in HL compared to LL condition. We also revealed an expected trend towards a stronger negative connectivity between the right AI and DLPFC in HL compared to LL condition. Our findings suggest that cognitively demanding task concurrent to food self-control task overloads AI and reduces the reinforcement of VS by AI. This helps in explaining how and why the affective processing of taste attributes, together with the cognitive processing of health attributes, may be disrupted under cognitive overload.