Cerebral Asymmetry and Hemispheric Lateralization in Neuroimaging

The human brain exhibits systematic left–right differences in anatomy and function, a phenomenon known as cerebral asymmetry. Hemispheric lateralization refers to the tendency for certain cognitive processes—such as language, visuospatial reasoning and motor control—to predominate in one hemisphere. Neuroimaging techniques, notably structural and diffusion magnetic resonance imaging (MRI), functional MRI and emerging deep‐learning approaches, have revealed how these asymmetries develop across the lifespan, vary between individuals and alter in neurological and psychiatric conditions. Quantitative measures of asymmetry support biomarkers of brain ageing, cognitive ability and disease progression, while genetic studies link microtubule‐related pathways to the establishment of left–right axes. Together, these insights illuminate fundamental organisational principles of the cerebral cortex, inform evolutionary theories of brain function and suggest avenues for precision diagnostics and rehabilitation.

Research from Nature Portfolio

Large‐scale multimodal MRI analyses have characterised age‐related trajectories of grey and white matter asymmetry in tens of thousands of adults. By deriving left and right metrics from structural and diffusion scans, researchers have introduced a hemispheric brain age (HBA) framework that complements conventional brain‐age estimates and highlights sex‐specific patterns of asymmetry change with advancing years.

Longitudinal studies across multiple adult‐lifespan cohorts demonstrate that regions exhibiting pronounced cortical thickness asymmetry in early adulthood undergo accelerated thinning of the previously thicker homotopic hemisphere with ageing. This dedifferentiation of asymmetry is further hastened in Alzheimer's disease, indicating that loss of hemispheric specialisation is a hallmark of neurodegeneration.

Genome‐wide association studies of regional surface area, thickness and subcortical volume asymmetries in over 30,000 participants have uncovered loci enriched for microtubule‐related genes. Such genetic variants not only underpin normal hemispheric axis formation but also overlap with those implicated in autism, schizophrenia and educational attainment, pointing to shared molecular mechanisms between lateralization and cognitive traits.

Cerebral Asymmetry and Hemispheric Lateralization in Neuroimaging publication trend

The graph below shows the total number of articles in cerebral asymmetry and hemispheric lateralization in neuroimaging across all publications each year (not limited to Nature Index journals).

Technical terms

Cerebral asymmetry: systematic morphological or functional differences between the left and right brain hemispheres.

Hemispheric lateralization: preferential dominance of one hemisphere for specific cognitive or sensorimotor processes.

Structural MRI: imaging modality that measures anatomical features such as cortical thickness and volume.

Diffusion MRI: technique that maps white matter microstructure by tracking water‐molecule diffusion along fibre pathways.

Hemispheric brain age (HBA): predictive metric estimating the relative biological age of each hemisphere based on multimodal MRI features.

Genome-wide association study (GWAS): statistical analysis that links genetic variants across the genome to quantitative traits, such as asymmetry indices.

References

1. Brain asymmetries from mid- to late life and hemispheric brain age. Nature Communications (2024).
2. Asymmetric thinning of the cerebral cortex across the adult lifespan is accelerated in Alzheimer’s disease. Nature Communications (2021).
3. The genetic architecture of structural left–right asymmetry of the human brain. Nature Human Behaviour (2021).
4. Optimality Pressures toward Lateralization of Complex Brain Functions. Physical Review X (2023).
5. Using a deep generation network reveals neuroanatomical specificity in hemispheres. Patterns (2024).
6. Tracing the development and lifespan change of population-level structural asymmetry in the cerebral cortex. eLife (2023).