The team utilised diffusion magnetic resonance imaging (MRI) to gather information on brain anatomy, which served as a model for the connectome. (Image: Shutterstock)
Published in the journal Nature on May 31, the study reveals a surprising finding about the relationship between brain structure and function.
A recent study titled Geometric Constraints on human brain function has challenged the prevailing belief that the connectome, the intricate web of nerves that link different regions of the cerebral cortex, is the primary driver of brain activity.
Led by David Van Essen, a neuroscientist from Washington University in St. Louis, Missouri, and co-authored by James Pang, a physicist at Monash University in Melbourne, Australia, the study compared two crucial components of the brain’s structure—the outer folds of the cerebral cortex and the connectome. Most higher-level brain activity occurs in the cerebral cortex, making it a focal point for understanding its function.
The researchers discovered that the shape of the outer surface of the cerebral cortex was a better predictor of brainwave data than the connectome. Pang explained that they used concepts from physics and engineering to explore how anatomy impacts brain function, highlighting the interdisciplinary nature of this study.
To delve deeper into the workings of the brain, the authors investigated how excited neurons communicate and influence brain activity. They sought to determine whether these excited neurons spread throughout the brain’s surface or through distant interconnections. Drawing on the mathematical theory of waves, the team uncovered that these waves can travel not only in one direction but also exhibit periodic oscillations, which was an intriguing finding.
The team utilised diffusion magnetic resonance imaging (MRI) to gather information on brain anatomy, which served as a model for the connectome. Researchers calculated the modes of brainwave for both the cortical surface and the connectome.
Upon analysis, it was found that brainwave modes, including those during the processing of visual stimuli and in the resting brain, were more effectively explained by the surface geometry model rather than the connectome model. However, Essen acknowledged the limitations of the diffusion MRI data used by the team, suggesting that the team should have also examined brain activity resulting from simple stimuli that only activate specific regions of the cortex. Pang, on the other hand, expressed curiosity in testing their models with such stimuli, considering the current analyses conducted by him and his co-authors as a preliminary demonstration.
