There is growing evidence that excessive body weight correlates with impaired cognitive performance like executive function, attention and memory. In our study, we applied a visual working memory task to quantify associations between body weight and executive function. In total, 34 lean (BMI 22 ± 2.1 kg/m2) and 34 obese (BMI 30.4 ± 3.2 kg/m2) subjects were included. Magnetic brain activity and behavioral responses were recorded during a one-back visual memory task with food and non-food pictures, which were matched for color, size and complexity. Behavioral responses (reaction time and accuracy) were reduced in obese subjects independent of the stimulus category. Neuronal activity at the source level showed a positive correlation between the right dorsolateral prefrontal cortex (DLPFC) activity and BMI only for the food category. In addition, a negative correlation between BMI and neuronal activity was observed in the occipital area for both categories. Therefore we conclude that increased body weight is associated with reduced task performance and specific neuronal changes. This altered activity is probably related to executive function as well as encoding and retrieval of information.Highlights
□ Reduced behavioral performance during working memory task is BMI dependent. □ Obese subjects have reduced neural activity during retrieve and encode of information. □ Correlation of activity in dorsolateral prefrontal cortex and BMI is food dependent.