Cortical microstructure and hemispheric specialization-A diffusion-imaging analysis in younger and older adults

Area of Science:

• Neuroscience
• Radiology
• Gerontology

Background:

• Cortical plasticity is crucial for understanding compensatory mechanisms and structural reserve in ageing.
• Cortical thickness (CT) provides limited insight into neuroplastic pathophysiology, unlike microstructural characteristics.
• Diffusion tensor imaging (DTI) measures like fractional anisotropy, axial diffusivity, and radial diffusivity offer sensitive indicators of cortical microstructural changes.

Purpose of the Study:

• To investigate microstructural correlates of hemispheric specialization using cortical DTI.
• To examine age-related effects on the lateralization of cortical DTI parameters.
• To compare age-dependent lateralization patterns between DTI measures and CT.

Main Methods:

• Analysis of DTI and CT data from 91 healthy younger and older adults.
• Extraction of data from regions within the Destrieux atlas.
• Assessment of diffusion measures (fractional anisotropy, axial diffusivity, radial diffusivity) and CT for lateralization and age effects.

Main Results:

• Diffusion measures demonstrated lateralization in specialized motor, language, visual, auditory, and inferior parietal cortices.
• Age-dependent increases in lateralization for DTI measures were observed in prefrontal, angular, superior temporal, and lateral occipital cortices.
• Cortical thickness (CT) did not exhibit any age-dependent alterations in lateralization.

Conclusions:

• Cortical DTI effectively captures microstructural properties linked to functional specialization, aligning with histological findings.
• Age-related changes in diffusion measures within prefrontal and parietal areas may illuminate atrophy-related plasticity in healthy ageing.
• DTI provides a more sensitive measure of age-related microstructural changes and lateralization compared to CT.