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

## TL;DR

This study introduces the structural-decoupling index to quantify how brain function varies independently of structure across regions, revealing a gradient linked to behavioral specialization from sensory to cognitive functions.

## Contribution

The paper presents a novel metric, the structural-decoupling index, and demonstrates its spatial variation correlating with behavioral and molecular brain features.

## Key findings

- Gradient from strongly coupled to decoupled regions across the brain
- Decoupling correlates with behavioral and molecular properties
- Supports the idea of functional specialization beyond structural constraints

## Abstract

The brain is an assembly of neuronal populations interconnected by structural pathways. Brain activity is expressed on and constrained by this substrate. Therefore, statistical dependencies between functional signals in directly connected areas can be expected higher. However, the degree to which brain function is bound by the underlying wiring diagram remains a complex question that has been only partially answered. Here, we introduce the structural-decoupling index to quantify the coupling strength between structure and function, and we reveal a macroscale gradient from brain regions more strongly coupled, to regions more strongly decoupled, than expected by realistic surrogate data. This gradient spans behavioral domains from lower-level sensory function to high-level cognitive ones and shows for the first time that the strength of structure-function coupling is spatially varying in line with evidence derived from other modalities, such as functional connectivity, gene expression, microstructural properties and temporal hierarchy.