Cortical thickness asymmetry from childhood to older adulthood.

Age-related thinning of the cortical mantle varies regionally, leading to hemispheric asymmetries in cortical thickness that may emerge at various stages of development and aging. Cortical asymmetry may play a role in modulating the functional maturation (or degradation) of language and cognition in humans, but its evolution over the lifespan is unknown. Here cortical thickness was negatively correlated with age in 274 5-59 year old, right-handed healthy participants. Pre-adolescents showed limited regions of cortical asymmetry focused on medial occipital lobe (R>L) and inferior frontal gyrus (R>L), namely vision and language relevant areas. More extensive frontal (lateral R>L, medial L>R) and parietal lobe (lateral L>R, medial R>L) asymmetries emerged after adolescence, and increased during aging. Changes of cortical asymmetry in these regions may be linked to specialization of the brain with maturity.