Central Nervous Processing of Visual Food Stimuli in Severely Obese Subjects

Cantonal Hospital of St. Gallen38 enrolled

Overview

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.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Obesity

Eligibility

Sex: FEMALEMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

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

Locations (1)

Outcomes

Primary Outcomes

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.

Time frame: 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 Outcomes

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.

Time frame: 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