Thesis advisor: Gorica Petrovich / Hunger and palatability modulate food intake through homeostatic and hedonic mechanisms that can work either independently, or in tandem. Both also influence food-seeking and learning about cues for food. Our prior work suggested that hunger and satiety impact motivation for palatable food differently in males and females. Sensitivity to food rewards also differs between adolescence and adulthood. Adolescents exhibit heightened motivation to consume and work for palatable food compared to adults. However, sex and age differences in palatable food motivation under sated and hungry conditions have not been explored. Here, we examined how rats consume and learn about palatable food. To assess cue-food associative learning and memory, rats underwent Pavlovian conditioning, extinction, and testing to assess the renewal of conditioned behavior. Male and female adult and adolescent Sprague Dawley rats were either food restricted (85% ad libitum body weight) or had ad libitum access to regular chow (n=8 per group). Rats learned palatable food-cue associations across 8 acquisition sessions, followed by cue-only presentations for 4 extinction sessions in a different context. They were then tested for renewal of conditioned responding (time spent at the food cup) to the food cue in the acquisition compared to extinction context. Before learning and after renewal testing, rats were tested for consumption of palatable food and chow in their home cage (1hr test/day per food). We found that adults and adolescents of both sexes were able to learn, extinguish, and renew conditioned responding regardless of hunger. Adolescents consistently had higher responding than adults across the learning and memory protocol. During consumption testing, females of both ages ate more palatable food than males, particularly when sated. Adolescent consumption was dependent on hunger state. Sated adolescents ate more palatable food than adults, and both sated adults and adolescents showed a preference for palatable food over chow. Food-deprived adolescents and adults ate similar amounts of chow, but only adults showed a preference for palatable food over chow. Palatable food consumption and conditioned responding during early acquisition training for that same food were positively correlated, indicating that hunger and satiety similarly impact palatable food-cue learning and consumption. Overall, these findings suggest that physiological hunger is not a prerequisite for successful associative learning and memory during adolescence or adulthood, and that female sensitivity to palatable food is present during adolescence. / Thesis (MA) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology and Neuroscience.

The purpose of this thesis is to assess dieting consumers’ perceptions of dessert advertisements containing subtle food cues. Participants were presented with one of three dessert advertisements depicting either, a dessert that had been left untouched, cut in half, or had a bite mark. Across the studies, the results show that the image of the bitten dessert is more preferred than the cut or whole desserts among participants with dieting experience. The relationship between dessert type and dieting is mediated via perceptions of realness/authenticity. The findings contribute to the literature on food consumption and advertising. Companies advertising low-fat products to dieting consumers can benefit from the results of these studies. / February 2017

Research on counteractive control theory suggests that exposure to food cues should bolster the dieting goal in restrained individuals. However, other research has found food cues to increase eating. The present study investigates whether cue specificity influences whether counteractive control or hyper-responsiveness to food cues takes precedence in dieters’ food selection and eating behavior. Restrained eaters were assigned to view a cookie, cake, or flower cue, then they selected a snack to take (apple or cookie). Participants also had an opportunity to eat cookies. Results showed that restrained participants exposed to the cake cue chose the apple more often than those receiving any other cue; exposure to a tempting cue not specific to the snack offered elicited counteractive control. However, participants exposed to either food cue ate more cookies than those exposed to the neutral cue. The role of food cue specificity in counteractive control and its limits are examined.

Research on counteractive control theory suggests that exposure to food cues should bolster the dieting goal in restrained individuals. However, other research has found food cues to increase eating. The present study investigates whether cue specificity influences whether counteractive control or hyper-responsiveness to food cues takes precedence in dieters’ food selection and eating behavior. Restrained eaters were assigned to view a cookie, cake, or flower cue, then they selected a snack to take (apple or cookie). Participants also had an opportunity to eat cookies. Results showed that restrained participants exposed to the cake cue chose the apple more often than those receiving any other cue; exposure to a tempting cue not specific to the snack offered elicited counteractive control. However, participants exposed to either food cue ate more cookies than those exposed to the neutral cue. The role of food cue specificity in counteractive control and its limits are examined.

Thesis advisor: Gorica D. Petrovich / Learned associations are formed when cues from the environment are paired with biologically important events and can later drive appetitive and aversive behaviors. These behaviors can persist and reappear after extinction because the original learned associations continue to exist. In particular, cues previously associated with food can later stimulate appetite and food consumption in the absence of hunger. Renewal, or reinstatement, of extinguished conditioned behaviors may help explain the mechanisms underlying persistent responding to food cues and difficulty associated with changing unhealthy eating habits. The aim of this dissertation was to determine key components in the neural circuitry mediating renewal of responding to food cues. The main focus was on the ventromedial prefrontal cortex (vmPFC; includes the infralimbic (ILA) and prelimbic (PL) areas) because that region was selectively recruited during context-dependent renewal (Chapter 3). In all of the experiments, the behavior and neural substrates of male and female rats were compared. It was important to examine both males and females because sex differences in context-mediated renewal were recently established: males consistently show renewal responding while females fail to do so (Chapters 2 and 3). The first study in this dissertation examined whether behavioral sex differences were driven by estradiol (Chapter 2) and whether the vmPFC is recruited during renewal responding (Fos induction; Chapter 3). Then, to establish the vmPFC is causal in driving the behavioral responding during renewal in a sex-specific way (Chapter 4), the vmPFC was silenced in males and stimulated it in females. This was accomplished using a chemogenetic methodology, DREADDs (Designer Receptors Exclusively Activated by Designer Drugs). Inhibiting the vmPFC in males blocks renewal responding. Reversely, stimulating the vmPFC in females resulted in renewal of responding. To determine key components of the vmPFC circuitry mediating renewal and whether these were different in males and females the experiments in Chapter 5 examined activation of PL inputs using a retrograde tract tracing combined with Fos detection design. The pathways to the PL from the ventral hippocampal formation (subiculum and CA1), the thalamus (anterior paraventricular nucleus), and the amygdala (anterior basolateral nucleus) were recruited in males and not recruited in females. This lack of recruitment could explain the lack of behavioral responding during renewal for females. Taken together, there are distinct and sex-specific circuitries recruited during context-mediated renewal. The findings from these experiments advanced our understanding of the neural mechanisms underlying sex differences in associative memory and contextual processing. They are also important for our understanding of the resilience of food cue to influence our consumption and diet choices. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.

Adult obesity is associated with increased morbidity and mortality. Increasing success in weight loss maintenance will decrease the prevalence of overweight and obesity, and therefore help control the adverse health effects of excess weight. Much is known about the behavioral characteristics of successful long-term weight loss maintenance, but less is known about the cognitive processes behind weight loss maintenance. The purposes of this study were to (1) identify differences in visual attention to high-energy dense foods between individuals who are normal weight, weight loss maintainers, and overweight/obese in a high-risk (food-buffet) situation; (2) to evaluate differences in food choices from a food buffet between weight status groups; (3) to analyze correlations between food attention and food choice across weight status groups. No significant differences were found between groups with respect to food attention or food choice. Overall, findings from this study may have been limited by methodology, technology, and sample size. Future research is needed to better understand the interaction of cognitive processes and weight loss maintenance.

Research documented the effectiveness of obesity surgery (OS) for long-term weight loss and improvements in medical and psychosocial sequelae, and general cognitive functioning. However, there is only preliminary evidence for changes in attentional processing of food cues after OS. This study longitudinally investigated visual attention towards food cues from pre- to 1-year post-surgery. Using eye tracking (ET) and a Visual Search Task (VST), attentional processing of food versus non-food cues was assessed in n = 32 patients with OS and n = 31 matched controls without weight-loss treatment at baseline and 1-year follow-up. Associations with experimentally assessed impulsivity and eating disorder psychopathology and the predictive value of changes in visual attention towards food cues for weight loss and eating behaviors were determined. During ET, both groups showed significant gaze duration biases to non-food cues without differences and changes over time. No attentional biases over group and time were found by the VST. Correlations between attentional data and clinical variables were sparse and not robust over time. Changes in visual attention did not predict weight loss and eating disorder psychopathology after OS. The present study provides support for a top-down regulation of visual attention to non-food cues in individuals with severe obesity. No changes in attentional processing of food cues were detected 1-year post-surgery. Further studies are needed with comparable methodology and longer follow-ups to clarify the role of biased visual attention towards food cues for long-term weight outcomes and eating behaviors after OS.