A scaffold for efficiency in the human brain

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Understanding the interplay between brain structure and function is crucial for cognitive neuroscience.
• The relationship between white matter (WM) microstructure and gray matter (GM) function, particularly during cognitive tasks, is not fully elucidated.
• Previous research has not comprehensively linked WM integrity, GM activity, and cognitive performance simultaneously.

Purpose of the Study:

• To investigate the associations between white matter microstructure, gray matter function, and cognitive performance in healthy adults.
• To explore how white matter integrity influences brain activity patterns during a working memory task.
• To determine if structure-function relationships predict task performance and individual differences.

Main Methods:

• Utilized diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) in younger and older healthy adults.
• Applied a novel multivariate Partial Least Squares (PLS) analysis to model relations between WM integrity and GM blood oxygenation level-dependent (BOLD) signals.
• Collected fMRI data during an n-back working memory task.

Main Results:

• Greater WM microstructural integrity was negatively associated with BOLD signal in task-positive GM regions, suggesting more efficient neural processing.
• Intact WM was linked to increased BOLD signal in task-negative regions during rest and a balanced BOLD response across task states.
• Structure-function relationships significantly predicted working memory task performance (accuracy and speed).
• These structure-function-behavior relationships accounted for individual differences beyond chronological age.

Conclusions:

• White matter microstructure acts as a critical scaffold supporting context-relevant gray matter function.
• Efficient cognitive processing relies on the integrity of structural brain connections.
• Brain structure-function relationships offer insights into individual cognitive capabilities and age-related differences.