Microstructural asymmetry in the human cortex

Area of Science:

• Neuroscience
• Human Brain Anatomy
• Neuroimaging

Background:

• The human cerebral cortex exhibits hemispheric asymmetry, but the underlying microstructural basis is not fully understood.
• Understanding microstructural asymmetry is crucial for comprehending brain function and individual differences.

Purpose of the Study:

• To investigate layer-specific microstructural asymmetry in the human cerebral cortex.
• To explore the heritability, developmental influences (age, sex), and functional/behavioral correlates of cortical microstructural asymmetry.

Main Methods:

• Analysis of layer-specific microstructural asymmetry using post-mortem brain tissue.
• In vivo imaging using Human Connectome Project (HCP) T1w/T2w data (N=1101).
• Validation with in vivo magnetization transfer (N=286) and quantitative T1 (N=50) measures.

Main Results:

• Layer-specific anterior-posterior asymmetry patterns were identified, with anterior regions showing leftward and posterior regions rightward asymmetry.
• In vivo asymmetry patterns, particularly in layer III, showed strong similarity to post-mortem findings.
• Microstructural asymmetry was found to be heritable, influenced by age and sex, and correlated with functional asymmetry.
• Differential associations between language, mental health markers, and microstructural asymmetry axes were observed.

Conclusions:

• The study reveals significant microstructural asymmetry in the human cerebral cortex across different layers.
• Cortical microstructural asymmetry is heritable, sex- and age-dependent, and functionally relevant.
• These findings provide insights into the developmental underpinnings of functional and behavioral divergence in the brain.