Central Nervous Processing of Visual Food Stimuli in Severely Obese Subjects

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

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 Overview

• Status: Completed
• Conditions: Obesity

• Study Type: Observational
• Enrollment (Actual): 38

Contacts and Locations

Study Locations

• Switzerland
  • Rorschach, Switzerland, 9400
    • Interdisciplinary Obesity Center, Cantonal Hospital St. Gallen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Severely obese (body mass index; BMI > 35 kg/m2) women and previously severely obese women who had undergone a Roux-en Y gastric bypass operation were recruited from the Interdisciplinary Obesity Center, cantonal hospital St. Gallen (Switzerland), and the adiposity platform of the University of Tübingen.

lean control women were recruited in St. Gallen and in Tübingen

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
severely obese women
Women after Roux-en Y gastric bypass surgery; 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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Cantonal Hospital of St. Gallen
• Collaborators: German Federal Ministry of Education and Research; Competence Network for Adiposity funded by the German Federal Ministry of Education and Research (FKZ: 01GI0837) and (FKZ: 01GI0849)
• Investigators: Principal Investigator: Bernd Schultes, Prof. Dr. med., Interdisciplinary Obesity Center, Kantonal Hospital St. Gallen, Rorschach, Switzerland; Principal Investigator: Niels Birbaumer, Prof. Dr., Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Tübingen, Germany

Study record dates

Study Major Dates

• Study Start: September 1, 2009
• Primary Completion (Actual): December 1, 2012
• Study Completion (Actual): December 1, 2012

Study Registration Dates

• First Submitted: December 2, 2011
• First Submitted That Met QC Criteria: December 14, 2011
• First Posted (Estimated): December 16, 2011

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 10, 2025
• Last Verified: March 1, 2013

More Information

Terms related to this study

• Keywords: severely obese; Roux-en Y gastric bypass surgery (RYGB); brain activity by fMRI; visual presentation of food and non-food-related pictures
• Other Study ID Numbers: EKSG09/033/2B; 09/033/2B (Other Identifier: ID by EKSG)