Trait-like variants in human functional brain networks

Abstract

Resting-state functional magnetic resonance imaging (fMRI) has provided converging descriptions of group-level functional brain organization. Recent work has revealed that functional networks identified in individuals contain local features that differ from the group-level description. We define these features as network variants. Building on these studies, we ask whether distributions of network variants reflect stable, trait-like differences in brain organization. Across several datasets of highly-sampled individuals we show that 1) variants are highly stable within individuals, 2) variants are found in characteristic locations and associate with characteristic functional networks across large groups, 3) task-evoked signals in variants demonstrate a link to functional variation, and 4) individuals cluster into subgroups on the basis of variant characteristics that are related to differences in behavior. These results suggest that distributions of network variants may reflect stable, trait-like, functionally relevant individual differences in functional brain organization.

Heritability of individualized cortical network topography

“…To advance our understanding of the biological bases of network organization, it is important to move from group-level parcellations to a level of granularity that is only accessible when studying network organization within the individual. Given that both the size and shape of individualized functional networks are tied to behavior 13,17,39,41 , it is critical to determine heritable sources of variation that govern the amount of cortex occupied by a given functional network.…”

“…For instance, broad classes of fingerprint types exhibit a high degree of heritability, despite ridge patterns of any fingerprint being entirely unique 67 . Likewise, the brain is organized into a core functional network architecture, that nevertheless exhibits distinctive features in a trait-like manner at the level of the individual 39 . Here, we demonstrate that the distinguishing topographic features of the brain, including variability in network organization and size, are influenced by inherited genetic factors (Figure 3).…”

“…Moreover, personalized network parcellations may be preferable for predictive modeling, graph theoretic, and imaging genetic approaches where the definition of an areal "unit" of cortex can influence downstream interpretations 38 . While the size and shape of individualized networks are stable across time 39 , predictive of behavior 13,40 and refined over the course of development 41 , the molecular and genetic bases of this variability in network size, location, and spatial arrangement remain to be established. Recent studies have shown that individual differences in functional connectivity are heterogeneous across the cortex, with greater variability in association cortex relative to unimodal regions 13,15,39,42 .…”

“…While the size and shape of individualized networks are stable across time 39 , predictive of behavior 13,40 and refined over the course of development 41 , the molecular and genetic bases of this variability in network size, location, and spatial arrangement remain to be established. Recent studies have shown that individual differences in functional connectivity are heterogeneous across the cortex, with greater variability in association cortex relative to unimodal regions 13,15,39,42 . This distribution Although prior twin studies establish the heritability of functional connectivity strength within population-average network templates 28,29,43,44 , the role of genetics in sculpting the spatial topography of the functional connectome has yet to be quantified.…”

Functional reorganization of brain networks across the human menstrual cycle

“…The network neuroscience community has begun to probe functional networks over 247 the timescale of weeks, months, and years to understand the extent to which brain 248 networks vary between individuals or within an individual over time 5,6,[26][27][28][29] . These 249 studies indicate that functional networks are dominated by common organizational 250 principles and stable individual features, especially in frontoparietal control regions 6,7,26,28 .…”