Summary: People who suffer from obesity have stronger connections between brain areas associated with the motivation to eat and the rewarding effect of food consumption. Additionally, researchers found noted differences in the thickness of the cerebral cortex of obese test subjects.
Source: University of Granada
A research group from Mind, Brain and Behaviour Research Centre (CIMCYC) of the University of Granada (UGR) has been studying the issue of excess weight from a neuroscientific perspective for many years, to determine the precise role played by the brain.
In a study recently published in the International Journal of Obesity—based on the doctoral thesis of Cristina Martín, which dealt with overweight adolescents—researchers from the UGR have found that that inferior weight loss among adolescents following a diet is linked to a stronger connection between the areas of the brain associated with the motivation to eat and the rewarding effect of food.
This finding adds to those previously obtained by the UGR’s Applied Neuropsychology and Psychoneuroimmunology Research Group in its work devoted to studying adolescents and adults, which shows how the brains of overweight people work differently from those of people of a healthy weight in all matters related to food.
“When faced with a decision about what best to eat and when presented with highly appetizing food, in terms of brain response we observed that the ‘impulsive’ circuits are more highly activated than the ‘reflective’ circuits,” explains Raquel Vilar López, a researcher at the UGR’s Department of Personality, Evaluation and Psychological Treatment and one of the authors of this work.
Different thickness in the cerebral cortex
In addition to these differences in brain activation, various areas of the brain in overweight people were found to differ in terms of how they connect and in the thickness of the cerebral cortex. There is also a link between these differences (which could be related to a diet high in fat) and the difficulty experienced by some people in following a diet and exercising, and therefore weight loss.
Based on these findings, researchers Raquel Vilar and Alfonso Caracuel of the UGR’s Department of Developmental and Educational Psychology, in collaboration with two international research groups, have recently started a project to combat the phenomenon of excess weight.
This involves a combination of training approaches that, individually, have proven effective in modifying imbalanced aspects in the functioning of the brain circuits involved in being overweight or obese. These approaches can be delivered online or in person.
About this obesity and neuroscience research news
Source: University of Granada
Contact: Press Office – University of Granada
Image: The image is in the public domain
Original Research: Closed access.
“Stressing diets? Amygdala networks, cumulative cortisol, and weight loss in adolescents with excess weight” by Cristina Martín-Pérez, Oren Contreras-Rodríguez, Juan Verdejo-Román, Raquel Vilar-López, Raquel González-Pérez & Antonio Verdejo-García. International Journal of Obesity
Stressing diets? Amygdala networks, cumulative cortisol, and weight loss in adolescents with excess weight
The amygdala is importantly involved in stress and obesity, but its role on weight change and diet-related stress remains unexplored among adolescents with excess weight. We aimed to examine the functional connectivity of the Central and Basolateral amygdala nuclei (CeA and BLA) among adolescents, and to explore the longitudinal association between brain connectivity measures and diet-related cortisol and weight loss in adolescents with excess weight.
We compared resting-state functional connectivity between adolescents with excess (EW, N = 34; Age = 16.44 ± 1.66) and normal weight (NW, N = 36; Age = 16.50 ± 1.40) using a seed-based (CeA and BLA) whole-brain approach. Then, in a subset of 30 adolescents with EW, followed-up after 3-months of dietary/lifestyle intervention, we explored for interactions between connectivity in the CeA/BLA networks and weight loss. Regression analyses were performed to explore the relationship between accumulated cortisol and weight loss, and to test the potential effect of the amygdala networks on such association.
In EW compared with NW, the CeA regions showed higher functional connectivity with anterior portions, and lower connectivity with posterior portions of the cingulate cortex, while the left BLA regions showed lower connectivity with the dorsal caudate and angular gyrus. In addition, higher connectivity between the left CeA-midbrain network was negatively associated with weight loss. Hair cortisol significantly predicted weight change (p = 0.012). However, this association was no longer significant (p = 0.164) when considering the CeA-midbrain network in the model as an additional predictor.
Adolescents with EW showed functional connectivity alterations within the BLA/CeA networks. The CeA-midbrain network might constitute an important brain pathway regulating weight change.