Central Nervous Processing of Visual Food Stimuli in Severely Obese Subjects

Study Overview
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Brief Summary
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Recent evidence has pointed to distinct alterations of brain functions in obese subjects some of which may even be causative for their obesity. The objective of this study was to examine food and non food related alterations in brain functions after excessive weight loss due to Roux-en Y gastric bypass surgery (RYGB), one of the most successful therapeutic approaches for long lasting weight loss. The investigators hypothesized that obese as compared with lean women show an altered activation pattern in the brain areas involved in the homeostatic regulation of eating behavior, i.e. the hypothalamus, in reward-related brain areas, such as the orbital frontal cortex (OFC) and the striatum as well as in prefrontal inhibitory control areas. Furthermore, the investigators hypothesized that women who had undergone a RYGB operation show a brain activity pattern that more closely mimics that of lean than severely obese women. In a supplementary test the investigators will assess gastrointestinal and metabolic response to a standardized meal in order to elucidate putative correlation of these responses with the results of fMRI scannings.

Official Title
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Central Nervous Processing of Visual Food Stimuli in Severely Obese Subjects and After Roux-en Y Gastric Bypass Surgery - a fMRI Study

Conditions
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Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: women with BMI > 35kg/m2 women, who had undergone gastric bypass surgery at least one year ago lean women Exclusion Criteria: known psychiatric or neurological diseases current medication with drug acting on the central nervous system drugs that are known to affect eating behavior contraindication for the fMRI scanning, e.g. metal implants or metal containing tattoos

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| severely obese women<br> | |
| Women after Roux-en Y gastric bypass surgery<br>Women recruited for this group had undergone Roux-en Y gastric bypass surgery at least one year before. In this women measurement of brain activity and gastrointestinal and metabolic response took place between 13 and 106 month after surgery. | |
| lean women<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| brain activity | In all women brain activity was assessed by functional magnetic resonance imaging (fMRI, BOLD Method, 1.5 Tesla fMRI Scanner, Siemens, Erlangen, Germany) during the presentation of food and non-food related pictures as well as during state conditions. In all three groups, brain activity was measured at a single time point. Of note, women, who had undergone Roux-en Y gastric bypass surgery were measured between 13 and 106 month after surgery. Brain activity was not measured before surgery in this group. | brain activity was measured at a single time point in all three groups; of note: women after Roux-en Y gastric bypass surgery were measured between 13 and 106 month after surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| gastrointestinal and metabolic responses to standardized meal | The gastrointestinal and metabolic responses to standardized meal were measured in the morning between 7:30 and 10:30 a.m. gastrointestinal and metabolic response were measured in all women at a single time point. Of note, women, who had undergone Roux-en Y gastric bypass surgery were measured between 13 and 106 month after surgery. Gastrointestinal and metabolic responses were not measured before surgery in this group. | measured at a single time point in all three groups; of note: women after Roux-en Y gastric bypass surgery were measured between 13 and 106 month after surgery at a single time point | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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severely obese, Roux-en Y gastric bypass surgery (RYGB), brain activity by fMRI, visual presentation of food and non-food-related pictures