Resting-state brain dynamics are associated with body fat percentage and sympathetic outflow in healthy adults

Purpose: Increased adiposity is associated with the development of cardio-metabolic disturbances, with sympathetic dysregulation playing a crucial role in the early phase. Both adiposity and chronic sympathetic activation may impair cerebral function increasing the risk of neurodegenerative diseases. How adiposity affects brain dynamics in the healthy state is not fully elucidated. Methods: We performed magnetoencephalography in 29 healthy participants (12 males and 17 females; aged 19–72, body fat percentage 7–45.3%) to record neural activity index as a measure of brain activity as well as functional connectivity using weighted phase lag index. Adiposity was assessed using body fat percentage and microneurography was used to assess muscle sympathetic nerve activity. Results: Individuals with higher fat percentage had higher muscle sympathetic nerve activity. Comparison of neural activity index between the groups showed significant differences in the left posterior cingulate cortex (delta and theta bands) and left precuneus (delta band). Significant differences in functional connectivity of the right superior frontal gyrus and left temporal pole (delta band) was also seen between groups. Neural activity index in the right caudate (theta and low-gamma bands) correlated positively with muscle sympathetic nerve activity while correlating negatively with body fat percentage. Conclusion: We have shown that resting-state brain activity and functional connectivity are different between healthy individuals with lower or higher body fat percentage. We have also shown that activity in key regions associated with adiposity also correlates with sympathetic outflow indicating the potential role of the sympathetic nervous system in driving adiposity-associated cardiometabolic complications.