Brain fingerprints along the language hierarchy

Abstract

Recent studies have shown that the brain functional connectome constitutes a unique fingerprint that allows the identification of individuals from a group. However, what information encoded in the brain that makes us unique remains elusive. Here, we addressed this issue by examining how individual identifiability changed along the language hierarchy. Subjects underwent fMRI scanning during rest and when listening to short stories played backward, scrambled at the sentence level, and played forward. Identification for individuals was performed between two scan sessions for each task as well as between the rest and task sessions. We found that individual identifiability tends to increase along the language hierarchy: the more complex the task is, the better subjects can be distinguished from each other based on their whole-brain functional connectivity profiles. A similar principle is found at the functional network level: compared to the low-order network (the auditory network), the high-order network is more individualized (the frontoparietal network). Moreover, in both cases, the increase in individual identifiability is accompanied by the increase in inter-subject variability of functional connectivities. These findings advance the understanding of the source of brain individualization and have potential implications for developing robust connectivity-based biomarkers.

Human brain mapping of homotopic functional affinity

“…In associative cortical areas like the default mode network and frontoparietal control network, the reliability of homotopic functional affinity is generally higher and consistent across datasets, aligning with the distribution patterns of other resting-state fMRI reliability metrics [14,55]. These cortical areas exhibit significant inter-individual variability [56] but relatively smaller intra-individual variation [57,58], making it easier to distinguish between individuals based on their activity patterns [59]. In regions like the central sulcus, orbitofrontal cortex, and insula, where blood oxygen level-dependent signals are constrained, the reliability of homotopic functional affinity in the Human Connectome Project (HCP) dataset tends to be higher than in the Chinese Human Connectome Project (CHCP).…”