General cognitive function and the brain's structural connectome

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• General cognitive function (g) involves flexible information processing.
• The brain's structural connectivity supporting 'g' is not fully understood.
• White matter integrity is crucial for cognitive abilities.

Purpose of the Study:

• To map the relationship between brain-wide structural connectivity and general cognitive function (g).
• To investigate how white matter network properties contribute to 'g' across the adult lifespan.
• To explore the convergence of grey and white matter contributions to cognition.

Main Methods:

• Utilized diffusion MRI data from 38,824 individuals across three cohorts.
• Employed meta-analytic associations using streamline count (SC), fractional anisotropy (FA), and mean diffusivity (MD) weightings.
• Examined global, nodal, and edge-level white matter associations with 'g', considering inter- and intra-hemispheric connectivity.

Main Results:

• 'g' is supported by a widely distributed white matter network spanning all cerebral lobes and subcortical structures.
• Associations between white matter properties and 'g' were observed at global, nodal, and edge levels.
• White matter findings mirrored cortical morphometry associations, indicating convergent grey and white matter influences.
• Age modulated these associations, with increased relevance of white matter integrity in older adults, particularly in frontal regions.

Conclusions:

• General cognitive function (g) is underpinned by a distributed structural communication backbone.
• The integrity of this white matter network is essential for cognitive performance and becomes increasingly important with age.
• Findings highlight the complex interplay between brain structure, connectivity, and cognitive abilities across adulthood.