Cognitive-affective correlates of pediatric food intake: Neural food cue reactivity and reward-related decision-making
Open Access
- Author:
- Fuchs, Bari
- Graduate Program:
- Nutritional Sciences
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- November 13, 2023
- Committee Members:
- Jennifer Williams, Major Field Member
Karolina Skibicka, Major Field Member
Kathleen Keller, Chair & Dissertation Advisor
Stephen Wilson, Outside Unit Member
Frank Hillary, Outside Field Member
Meg Bruening, Program Head/Chair - Keywords:
- eating behaviors
food intake
fmri
decision-making
pediatric
obesity - Abstract:
- Between 2017 and 2020, over 20% of children in the United States had obesity. As diet and behavioral interventions to treat and prevent obesity are ineffective or produce small and variable effects, a better understanding of the factors that facilitate increased energy intake is needed. Theoretical models posit that psychological, physiological, and neural responses to food cues (i.e., food cue reactivity) and reward-related decision-making (RRDM) promote overeating and susceptibility to obesity in the present-day food environment. These theories are supported by research showing behavioral and neural responses to food cues are associated with eating behaviors and weight gain, and reward learning, executive functioning, and decision-making are altered in obesity. Nevertheless, it remains unclear how food cue reactivity and RRDM relate to pediatric eating behaviors. Therefore, this dissertation examined how neural responses to food cues (chapters 2 and 3) and decision-making processes (chapter 4) relate to laboratory-assessed food intake in children. To shed light on the mechanisms that increase intake in response to large portions of food (i.e., the portion size effect; PSE), chapter 2 examined neural responses to food and non-food (office supplies) images presented in larger and smaller (i.e., age-appropriate) amounts. On average, neural responses to amount (larger vs. smaller) were stronger but less extensive in visual processing areas for foods relative to office supplies. Neural responses to food energy density (kcal/g; higher vs. lower) differed in extent between larger and smaller amounts in regions implicated in value-based decision-making (orbitofrontal cortex, ventromedial prefrontal cortex). These results highlight potentially distinct neural pathways for encoding food energy content and quantity. To build on chapter 2, chapter 3 examined how neural responses to food portion size cues relate to children’s susceptibility to the PSE. To do so, neural responses to food amount (larger vs. smaller) were regressed on individual-level linear and quadratic relationships between intake and portion size, estimated from children’s intake data at four meals that varied in portion size. Relationships were examined within the appetitive network and cerebellum to extend prior work examining these associations in reward- and control-related brain regions. Response to food amount in cerebellar lobules IV-VI was negatively associated with the quadratic portion size slope; greater activation to larger portions was associated with smaller increases or larger decreases in intake as portions got larger, while greater activation to smaller portions was associated with greater increases in intake as portions got larger. Neural responses within the appetitive network were not associated with linear or quadratic portion size slopes. These results suggest decreased cerebellar activation in response larger amounts of food may increase children’s susceptibility to overeating when faced with “supersized” portions of food. While chapters 2 and 3 shed light on the neural correlates of the PSE, they did not elucidate specific cognitive or affective processes that drive eating behaviors. Therefore, chapter 4 examined the relationships between decision-making processes and food intake in children. Decision-making was assessed with a task where children make selections with unknown reward outcomes, and decision-making processes were quantified with a reinforcement learning model. Food intake was measured with three paradigms: (1) a standard ad libitum meal, (2) an eating in the absence of hunger (EAH) protocol, and (3) a palatable buffet meal. Decision-making processes that influence the tendency to repeatedly make the same choice (i.e., perseverate) were associated with energy intake: (1) increases in the tendency to perseverate after a gain were positively associated with intake at all three paradigms and indirectly associated with higher weight status through standard and buffet meal intake, and (2) increases in the tendency to perseverate after a loss were positively associated with EAH, but only in children whose tendency to perseverate persisted across trials. These results suggest that children who are more likely to repeat a behavior after a reward have a tendency to eat more at laboratory meals. If this generalizes to contexts outside the laboratory, these children may be susceptible to obesity. Together, these chapters sheds light on how stimulus-driven (Pavlovian, operant) and goal-directed decision-making systems relate to food intake and the development of obesity: (1) chapter 2 suggests that brain regions implicated in valuation and goal-directed decision-making differentially process food cues based on energy density and portion size, (2) chapter 3 suggests that a brain region implicated in the modulation of stimulus-driven and goal-directed signals influences susceptibility to the portion size effect, and (3) chapter 4 suggests that operant conditioning increases food intake and can contribute to the development of pediatric obesity. These findings may help identify children who are at risk for overeating, but future research is needed to assess whether results generalize to more diverse samples. For insight into causal relationships between cognitive-affective processes and food intake, experimental and longitudinal studies are needed.