Elevated BMI impacts brain-state dynamics within the sensorimotor-to-transmodal hierarchy.

Area of Science:

• Neuroscience
• Medical Imaging
• Psychiatry

Background:

• Overweight and obesity (high BMI) are linked to brain functional changes, potentially causing cognitive and emotional issues.
• The specific brain dynamic alterations associated with obesity remain unclear.

Purpose of the Study:

• To investigate how body mass index (BMI) affects brain activity states and dynamics.
• To explore the relationship between BMI, brain dynamics, and functional outcomes like cognitive decline and mental illness.

Main Methods:

• Utilized resting-state functional magnetic resonance imaging (fMRI) data from two large independent datasets (N=1923 and N=998).
• Employed a Hidden Markov model to analyze spatiotemporal brain activity states.
• Examined changes in brain-state dynamics and their correlation with BMI and functional outcomes, including longitudinal data validation.

Main Results:

• Increased BMI shifts brain activity towards sensorimotor system states, hindering transitions to transmodal system states.
• These findings were confirmed in a longitudinal study showing BMI increase correlated with altered brain dynamics.
• Altered brain-state dynamics were found to mediate the association between BMI and adverse outcomes, such as cognitive decline and mental illness symptoms.

Conclusions:

• Obesity-related alterations in brain-state dynamics, particularly within the sensorimotor-to-transmodal hierarchy, offer new insights.
• These findings contribute to understanding the neural mechanisms underlying obesity-related brain dysfunction and mental health challenges.