Food-Predicting Stimuli Differentially Influence Eye Movements and Goal-Directed Behavior in Normal-Weight, Overweight, and Obese Individuals

Abstract

Obese individuals have been shown to exhibit abnormal sensitivity to rewards and reward-predicting cues as for example food-associated cues frequently used in advertisements. It has also been shown that food-associated cues can increase goal-directed behavior but it is currently unknown, whether this effect differs between normal-weight, overweight, and obese individuals. Here, we investigate this question by using a Pavlovian-to-instrumental transfer (PIT) task in normal-weight (N = 20), overweight (N = 17), and obese (N = 17) individuals. Furthermore, we applied eye tracking during Pavlovian conditioning to measure the participants’ conditioned response as a proxy of the incentive salience of the predicted reward. Our results show that the goal-directed behavior of overweight individuals was more strongly influenced by food-predicting cues (i.e., stronger PIT effect) than that of normal-weight and obese individuals (p < 0.001). The weight groups were matched for age, gender, education, and parental education. Eye movements during Pavlovian conditioning also differed between weight categories (p < 0.05) and were used to categorize individuals based on their fixation style into “high eye index” versus “low eye index” as well. Our main finding was that the fixation style exhibited a complex interaction with the weight category. Furthermore, we found that normal-weight individuals of the group “high eye index” had higher body mass index within the healthy range than individuals of the group “low eye index” (p < 0.001), but this relationship was not found within in the overweight or obese groups (p > 0.646). Our findings are largely consistent with the incentive sensitization theory predicting that overweight individuals are more susceptible to food-related cues than normal-weight controls. However, this hypersensitivity might be reduced in obese individuals, possibly due to habitual/compulsive overeating or differences in reward valuation.

Effects of hM4Di activation in CamKII basolateral amygdala neurons and CNO treatment on Sensory-Specific vs. General-PIT; refining PIT circuits and considerations for using CNO

“…However, it is worth noting that evidence for the necessity of the BLA in the expression of Pavlovian outcome devaluation effects is mixed. Some studies have supported its role (Baxter et al, 2000;Johnson et al, 2009;Lichtenberg et al, 2017) and yet others mentioned above, (Blundell et al, 2003;Pickens et al, 2003;Wellman et al, 2005), and our current results, show that disruption of the BLA at the time of testing does not alter the expression of Pavlovian devaluation effects. Among these studies, only two conducted manipulations of the BLA at the time of testing, as we did here (Wellman et al, 2005;Lichtenberg et al, 2017).…”

“…This phenomenon is thought to play an important role in a wide range of behaviors that are essential for survival, and in the development of problematic appetitive behaviors that drive addictions and obesity (Wyvell Berridge, 2000;Berridge Robinson, 2003;Bouton, 2011;Boutelle Bouton, 2015;Alonso-Caraballo et al, 2018;Derman Ferrario, 2018;Watson et al, 2018). Consistent with the preclinical literature, studies in humans also find support for alterations in PIT and its underlying neural and psychological processes in obesity and internet gaming disorders (Lehner et al, 2017;Vogel et al, 2018). Thus, understanding the neural basis of PIT is critical for addressing normal and aberrant motivation.…”

Appetitive Pavlovian-to-Instrumental Transfer in Participants with Normal-Weight and Obesity

“…A widely used bias-vulnerability test is Pavlovian-to-Instrumental Transfer (PIT) [20,22,23,24], which measures the influence of task-irrelevant cues on behavior. Past research has resulted in mixed findings concerning food-related PIT and body weight [25,26,27,28]. Given the uncertain link between automatic behaviors, vulnerability to food-related environmental cues and weight development, we aimed to further investigate this issue.…”

Enhanced incentive motivation in obesity-prone rats is mediated by NAc core CP-AMPARs

“…These cues include sensory properties of food itself, like the crunching sensation of digging your hand into a bag of potato chips, as well as distal cues like packaging, and branding logos ( Bouton, 2011 ). The ability for food cues to trigger cravings is not unique to obese populations, but rather individuals that struggle to maintain a healthy weight are more sensitive to these motivational properties of food cues ( Fedoroff et al, 1997 ; Ferriday and Brunstrom, 2011 ; Jansen et al, 2008 ; Lehner et al, 2017 ; see Small, 2009 for review). This suggests that brain regions mediating incentive motivation, such as the NAc ( Berridge et al, 2009 , 2010 ; Cartoni et al, 2016 ; Holmes et al, 2010 ), differ functionally between obesity-susceptible vs. -resistant populations, thereby contributing to overconsumption in susceptible individuals ( Burger and Stice, 2014 ; Stoeckel et al, 2008 ; Tomasi and Volkow, 2013 ).…”