Decoupling of brain function from structure reveals regional behavioral specialization in humans

Area of Science:

• Neuroscience
• Brain mapping
• Systems neuroscience

Background:

• The brain's neuronal populations are interconnected by structural pathways, influencing brain activity.
• The extent to which brain function is constrained by its underlying wiring (structure-function coupling) is not fully understood.
• Previous studies suggest a relationship, but a quantitative measure and macroscale understanding are lacking.

Purpose of the Study:

• To introduce a novel metric, the structural-decoupling index, to quantify the strength of coupling between brain structure and function.
• To identify and characterize macroscale gradients of structure-function coupling across the human brain.
• To investigate how this coupling varies across different behavioral domains, from sensory processing to higher cognition.

Main Methods:

• Development and application of the structural-decoupling index.
• Analysis of macroscale brain data to identify gradients.
• Comparison with realistic surrogate data to establish significance.
• Correlation with behavioral domains and other neuroimaging modalities.

Main Results:

• A macroscale gradient of structure-function coupling was revealed across brain regions.
• Regions showed varying degrees of coupling, deviating from expectations based on surrogate data.
• This gradient spans from lower-level sensory functions to higher-level cognitive functions.
• The spatial variation in structure-function coupling aligns with findings from functional connectivity, gene expression, and microstructural properties.

Conclusions:

• The strength of structure-function coupling is not uniform across the brain but exhibits a spatially varying gradient.
• This gradient reflects a fundamental organizational principle of the brain, linking its physical wiring to its functional operations.
• The findings provide a new framework for understanding brain organization and offer insights into the relationship between brain structure and cognitive function.