Structure-function interplay as signature for brain decoding and fingerprinting

Brain signatures of functional activity have shown promising results in both decoding brain states; i.e., determining whether a subject is at rest or performing a given task, and fingerprinting, that is identifying individuals within a large group. Importantly, these brain signatures do not account for the underlying brain anatomy on which brain function takes place. Here, we leveraged brain structure-function coupling as a new imaging-based biomarker to characterize tasks and individuals. We used multimodal magnetic resonance imaging and the recently introduced Structural-Decoupling Index (SDI) to quantify regional structure-function interplay in 100 healthy volunteers from the Human Connectome Project, both during rest and seven different tasks. SDI allowed accurate classifications for both decoding and fingerprinting, outperforming functional signatures. Further, SDI profiles in resting-state correlated with individual cognitive traits. These results show that brain structure-function interplay contains unique information which provides a new class of signatures of brain organization and cognition.