Relationship between brain and cognitive processes in Down syndrome.

We investigated regional grey matter (GM) density in adolescents with Down syndrome (DS) compared to age-matched controls and correlated MRI data with neuropsychological measures in the DS group. Inter-group comparisons documented several GM concentration abnormalities in the participants with DS compared to controls. In the adolescents with DS, intra-group results also showed associations between regional GM density and the neuropsychological measures considered. In particular, GM density of the cerebellum and middle and inferior temporal gyrus was associated with linguistic measures. Short-term memory performances were correlated with the inferior parietal lobule, insula, superior temporal gyrus, medial occipital lobe, and cerebellum. Long-term memory abilities were correlated with GM density in the orbitofrontal cortex, lateral and medial temporal lobe regions, and anterior cingulum and visuo-perceptual abilities with GM density the left middle frontal gyrus. Results of this preliminary study are consistent with a not always efficient brain organization in DS.