Lateralization of the arcuate fasciculus from childhood to adulthood and its relation to cognitive abilities in children

Abstract

The arcuate fasciculus is a major white matter tract involved in language processing that has also been repeatedly implicated in intelligence and reasoning tasks. Language in the human brain is lateralized in terms of both function and structure, and while the arcuate fasciculus reflects this asymmetry, its pattern of lateralization is poorly understood in children and adolescents. We used diffusion tensor imaging (DTI) and tractography to examine arcuate fasciculus lateralization in a large (n = 183) group of healthy right-handed volunteers aged 5-30 years; a subset of 68 children aged 5-13 years also underwent cognitive assessments. Fractional anisotropy and number of streamlines of the arcuate fasciculus were both significantly higher in the left hemisphere than the right hemisphere in most subjects, although some subjects (10%) were right lateralized. Age and gender effects on lateralization were not significant. Children receiving cognitive assessments were divided into three groups: a "left-only" group in whom only the left side of the arcuate fasciculus could be tracked, a left-lateralized group, and a right-lateralized group. Scores on the Peabody Picture Vocabulary Test (PPVT) and NEPSY Phonological Processing task differed significantly among groups, with left-only subjects outperforming the right-lateralized group on the PPVT, and the left-lateralized children scoring significantly better than the right-lateralized group on phonological processing. In summary, DTI tractography demonstrates leftward arcuate fasciculus lateralization in children, adolescents, and young adults, and reveals a relationship between structural white matter lateralization and specific cognitive abilities in children.

The dynamic imprint of word learning on the dorsal language pathway

“…Consistent with our results, DTI studies revealed that Vocabulary scores and phonological processing were related to a stronger degree of lateralization of the arcuate fasciculus in the left hemisphere (Lebel and Beaulieu 2009). Thus, individual differences in vocabulary size contribute to determining vocabulary acquisition mediated by the left STG and IFG.…”

Abnormal White Matter Properties in Adolescent Girls With Anorexia Nervosa

“…In addition, we were unable to identify the Arc-R in 2 AN subjects. We attribute the difficultly in identifying the Arc-R to limitations of deterministic tractography approaches that cannot account for higher tract curvature and increased partial voluming with the aSLF-R, a finding consistent with several other reports (Catani et al, 2007;Lebel and Beaulieu, 2009;Mishra et al, 2010;Yeatman et al, 2011).…”

Attention Deficit Hyperactivity Disorder

“…DTI has provided the basis for much of this work, demonstrating, for instance, that intellectual functioning in youth is associated with the development of white matter circuitry in bilateral frontal, occipito-parietal, and occipitotemporo-parietal regions (Schmithorst et al 2005). In addition, the reading skills of children and adolescents improve with white matter changes in the internal capsule, corona radiata, and temporo-parietal regions (Beaulieu et al 2005;Nagy et al 2004;Niogi and McCandliss 2006;Qiu et al 2008), and greater left lateralization of the arcuate fasciculus fibers is associated with improved phonological processing and receptive vocabulary (Lebel and Beaulieu 2009). Visuospatial working memory capacity is linked to a fronto-intraparietal network (Olesen et al 2003), while better visuospatial construction and psychomotor performance is associated with high corpus callosum fractional anisotropy (Fryer et al 2008).…”