Changes in Inhibition and Valuation After Eating

Study Overview
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Brief Summary
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An impaired ability to exert control has been implicated in bulimia nervosa (BN), but this impairment may not represent a stable trait or be the most effective focus for treatment. This project aims to understand how predictions and value-based decisions about control may be abnormally influenced by eating in individuals with BN, thereby maintaining cycles of binge eating, purging, and restriction.

Detailed Description
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The overarching goal of this project is to test a neurocomputational model of BN that incorporates learning and decision-making components of control. The study combines functional magnetic resonance imaging (fMRI), computational modeling, and real-time mobile assessments to examine the influences of acute fasting and eating on brain function and associated control-related updating and effort-valuation processes in BN. More specifically, the study has the following main objectives: 1) To determine the influence of eating on control-related prediction updating in BN.; 2) To determine the influence of eating on control-related cognitive effort valuation in BN; 3) To use state-specific neural activation to predict BN symptoms.

Official Title
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Dynamic Neural Computations Underlying Cognitive Control in Bulimia Nervosa

Conditions
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Bulimia Nervosa

Intervention / Treatment
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* Other: Fasting state
* Other: Fed state
* Other: Magnetic Resonance Imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female Aged 18 to 45 years Current BMI greater than or equal to 18.5kg/m2 but under 30kg/m2 Right-handed English-speaking Additional Inclusion Criteria for Women with Bulimia Nervosa: Meet DSM-5 criteria for bulimia nervosa Exclusion Criteria: Medical instability Ongoing medical treatment, medical condition, or psychiatric disorder that may interfere with study variables or participation Shift work Pregnancy, planned pregnancy, or lactation during the study period Allergy to any of the ingredients in or unwillingness to consume the standardized meal or unwillingness to drink water during the fasting period Any contraindication for fMRI

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Two participant groups (one with and one without bulimia nervosa) will be scanned using MRI after they have fasted and after they have consumed a standardized meal. The order of these two scans will be counterbalanced across groups.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Participants with Bulimia Nervosa<br>Participants are randomly assigned (in even numbers across the two groups) to scan order: A. These participants are first scanned after 16 hours of fasting on one day, and are next scanned after a standardized meal on a second day. B. These participants are first scanned after a standardized meal on one day, and are next scanned after 16 hours of fasting on a second day. | Other: Fasting state<br>* 16 hours of fasting<br>Other: Fed state<br>* Fed a standardized meal<br>Other: Magnetic Resonance Imaging<br>* Neuroimaging with computational modeling<br>* Other names: MRI;|
| Active Comparator: Participants without Bulimia Nervosa<br>Participants are randomly assigned (in even numbers across the two groups) to scan order: A. These participants are first scanned after 16 hours of fasting on one day, and are next scanned after a standardized meal on a second day. B. These participants are first scanned after a standardized meal on one day, and are next scanned after 16 hours of fasting on a second day. | Other: Fasting state<br>* 16 hours of fasting<br>Other: Fed state<br>* Fed a standardized meal<br>Other: Magnetic Resonance Imaging<br>* Neuroimaging with computational modeling<br>* Other names: MRI;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frontostriatal Activation Associated with Prediction Errors on the Stop Signal Task | Blood oxygen level dependent (BOLD) signal in frontostriatal brain circuitry associated with inhibitory control prediction errors | 1-2.5 hours after a 16-hour fast (fasted state) | 
| Frontostriatal Activation Associated with Prediction Errors on the Stop Signal Task | Blood oxygen level dependent (BOLD) signal in frontostriatal brain circuitry associated with inhibitory control prediction errors | 1-2.5 hours after a standardized meal (fed state) | 
| Frontostriatal Activation Encoding the Subjective Value of Cognitive Effort on the Cognitive-Effort Discounting Task | Blood oxygen level dependent (BOLD) signal in frontostriatal brain circuitry associated with the subjective value of expending cognitive effort on control | 1-2.5 hours after a 16-hour fast (fasted state) | 
| Frontostriatal Activation Encoding the Subjective Value of Cognitive Effort on the Cognitive-Effort Discounting Task | Blood oxygen level dependent (BOLD) signal in frontostriatal brain circuitry associated with the subjective value of expending cognitive effort on control | 1-2.5 hours after a standardized meal (fed state) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent correct responses to stop trials and the trial-by-trial association | Behavioral performance on the stop signal task, as measured by percent correct responses to stop trials and the trial-by-trial association between the predicted likelihood that upcoming inhibition is needed (P(stop)) from a Bayesian ideal observer model and accuracy | 1-2.5 hours after a 16-hour fast (fasted state) | 
| Percent correct responses to stop trials and the trial-by-trial association | Behavioral performance on the stop signal task, as measured by percent correct responses to stop trials and the trial-by-trial association between the predicted likelihood that upcoming inhibition is needed (P(stop)) from a Bayesian ideal observer model and accuracy | 1-2.5 hours after a standardized meal (fed state) | 
| Cognitive Effort Discounting Task Behavioral Performance | The subjective value of cognitive effort estimated for each N-back load level and cost- and benefit-modulated drift rate parameters from a drift- diffusion model applied to behavioral performance data | 1-2.5 hours after a 16-hour fast (fasted state) | 
| Cognitive Effort Discounting Task Behavioral Performance | The subjective value of cognitive effort estimated for each N-back load level and cost- and benefit-modulated drift rate parameters from a drift- diffusion model applied to behavioral performance data | 1-2.5 hours after a standardized meal (fed state) | 
| Binge-eating Severity | The frequency of binge-eating episodes as assessed by the Eating Disorder Examination (EDE) and Ecological Momentary Assessment (EMA). Binge-eating frequency has a minimum limit of 0 and no maximum limit. A higher score indicates a greater severity. | Baseline and 6-month follow-up | 
| Compensatory Behavior Severity | The frequency of compensatory behaviors as assessed by the EDE and EMA. This frequency has a minimum limit of 0 and no maximum limit. A higher score indicates a greater severity. | Baseline and 6-month follow-up | 
| Dietary Restriction Severity | The frequency of fasting episodes as assessed by the EDE avoidance of eating item (minimum limit = 0, maximum limit = 6); the severity of dietary restriction as assessed by the Eating Pathology Symptoms Inventory (EPSI) - restricting subscale (minimum limit=0; maximum limit=24), and the frequency of restrictive eating behaviors as assessed by EMA (minimum limit=0; no maximum limit). On all measures, a higher score indicates a greater severity. | Baseline and 6-month follow-up |