Increased Resting-State Functional Connectivity in Obese Adolescents; A Magnetoencephalographic Pilot Study

Abstract

BackgroundObesity is not only associated with metabolic abnormalities, but also with cognitive dysfunction and changes in the central nervous system. The present pilot study was carried out to investigate functional connectivity in obese and non-obese adolescents using magnetoencephalography (MEG).Methodology/Principal FindingsMagnetoencephalographic recordings were performed in 11 obese (mean BMI 38.8±4.6 kg/m2) and 8 lean (mean BMI 21.0±1.5 kg/m2) female adolescents (age 12–19 years) during an eyes-closed resting-state condition. From these recordings, the synchronization likelihood (SL), a common method that estimates both linear and non-linear interdependencies between MEG signals, was calculated within and between brain regions, and within standard frequency bands (delta, theta, alpha1, alpha2, beta and gamma). The obese adolescents had increased synchronization in delta (0.5–4 Hz) and beta (13–30 Hz) frequency bands compared to lean controls (P delta total = 0.001; P beta total = 0.002).Conclusions/SignificanceThis study identified increased resting-state functional connectivity in severe obese adolescents. Considering the importance of functional coupling between brain areas for cognitive functioning, the present findings strengthen the hypothesis that obesity may have a major impact on human brain function. The cause of the observed excessive synchronization is unknown, but might be related to disturbed motivational pathways, the recently demonstrated increase in white matter volume in obese subjects or altered metabolic processes like hyperinsulinemia. The question arises whether the changes in brain structure and communication are a dynamic process due to weight gain and whether these effects are reversible or not.

Association between increased BMI and severe school absenteeism among US children and adolescents: findings from a national survey, 2005–2008

“…Magnetic source imaging suggested a link between increased body weight and pathological alteration in cortical communication processes in the central nervous system among adolescents. 19 White matter lesions in the brain of children younger than 10 years with early onset obesity but not sibling controls was also demonstrated. 20 It is postulated that early exposure to pathological changes in the brain, including alterations in levels of adipokines, hormones or neurotransmitters, may have detrimental effects on the rapid growth of the central nervous system during childhood when the brain is known to be more susceptible to adverse factors.…”

Relationships among Obstructive Sleep Apnea, Anthropometric Measures, and Neurocognitive Functioning in Adolescents with Severe Obesity

“…The relationships between OSA and neurocognitive functioning in the obese adolescent population are relatively unexplored. Decreased cognitive functioning among a large sample of obese children has been shown and functional changes have been demonstrated in the brains of obese adolescents compared with lean adolescents (14). However, information is lacking on the additional burden of OSA and whether OSA was a contributing factor to these observations.…”

An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children

“…A potential interpretation is that the control group increased synchrony over time within specific brain regions as they developed a pattern of excessive synchrony associated with obesity. Cross-sectional studies in both adolescents and adults have indicated that obese participants show greater synchrony between various brain regions compared to their healthier peers (Nummenmaa et al, 2012; Olde Dubbelink et al, 2008). Future studies should compare the longitudinal development of brain function in obese and healthy weight children to investigate these possible differences in developmental trajectories.…”