Neurotransmitters Contribute Structure-Function Coupling: Evidence from Grey Matter Volume (GMV) and Brain Entropy (BEN)

The emergence of human brain function from macroscopic anatomical structures and its relationship with the coupling of structure and function have long been pivotal questions in neuroscience. Neurotransmitter receptors are critical in signal transmission, regulating brain function, and potentially enhancing the coupling between brain structure and function. Recent research suggests that neurotransmitter systems facilitate this coupling between structural and functional networks. However, the mechanisms of how neurotransmitters adapt to local anatomical structures and drive functional emergence are not yet fully understood. This study explores these mechanisms using gray matter volume (GMV) and brain entropy (BEN). BEN reflects the irregularity, unpredictability, and complexity of brain activity, and functional MRI (fMRI)-based BEN has identified its distribution in the normal human brain. BEN is correlated to cognitive and task performance, and aberrant BEN patterns link to various brain disorders. Notably, BEN can indicate neuroplasticity through non-invasive brain stimulation, and pharmacological intervention. We analyzed structural imaging data, as well as 7T resting-state and movie-watching fMRI data from 176 participants in the Human Connectome Project (HCP), to calculate GMV, resting-state BEN (rsBEN), and movie-watching BEN (mvBEN). By integrating data from the publicly available neurotransmitter receptors database, we evaluated the role of neurotransmitters in the coupling between GMV and rsBEN, GMV and mvBEN, and rsBEN and mvBEN. Our findings reveal that neurotransmitters significantly contribute to structural and functional coupling and influence the transition from task-free to movie-watching conditions.