Hemispheric Asymmetries of Individual Differences in Functional Connectivity

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• Resting-state functional magnetic resonance imaging (fMRI) reveals stable, individual differences in large-scale brain network organization.
• These unique deviations, termed network variants, exhibit a characteristic spatial distribution that may differ between brain hemispheres.

Purpose of the Study:

• To systematically investigate hemispheric differences in the spatial distribution and characteristics of network variants using Human Connectome Project data.
• To explore how these variant asymmetries relate to typical network distributions and functional lateralization.

Main Methods:

• Analysis of resting-state fMRI data from the Human Connectome Project.
• Identification and spatial mapping of network variants across hemispheres.
• Comparison of variant distribution with group-average network asymmetries.

Main Results:

• Network variants were significantly larger in the right hemisphere, particularly in the frontal operculum and medial frontal cortex.
• Left-hemisphere variants were most common around the temporoparietal junction (TPJ).
• Variant asymmetries influenced group-average network asymmetries, sometimes amplifying and sometimes counteracting them. Differences were observed between left- and right-handers for specific networks.

Conclusions:

• Idiosyncratic brain organization, as reflected by network variants, exhibits systematic hemispheric differences.
• These asymmetries provide insights into developmental constraints on network variants.
• Variant asymmetries may be linked to lateralized brain functions and traits.