Microstructural asymmetry of the corticospinal tracts predicts right–left differences in circle drawing skill in right-handed adolescents

Abstract

Most humans show a strong preference to use their right hand, but strong preference for the right hand does not necessarily imply a strong right–left asymmetry in manual proficiency (i.e., dexterity). Here we tested the hypothesis that intra-individual asymmetry of manual proficiency would be reflected in microstructural differences between the right and left corticospinal tract (CST) in a cohort of 52 right-handed typically-developing adolescents (11–16 years). Participants were asked to fluently draw superimposed circles with their right dominant and left non-dominant hand. Temporal regularity of circle drawing movements was assessed for each hand using a digitizing tablet. Although all participants were right-handed, there was substantial inter-individual variation regarding the relative right-hand advantage for fluent circle drawing. All subjects underwent whole-brain diffusion tensor imaging at 3 Tesla. The right and left CST were defined as regions-of-interest and mean fractional anisotropy (FA) and diffusivity values were calculated for right and left CST. On average, mean FA values were higher in the left CST relative to right CST. The degree of right–left FA asymmetry showed a linear relationship with right–left asymmetry in fluent circle drawing after correction for age and gender. The higher the mean FA values were in the left dominant CST relative to the right non-dominant CST, the stronger was the relative right-hand advantage for regular circle drawing. These findings show that right–left differences in manual proficiency are highly variable in right-handed adolescents and that this variation is associated with a right-left microstructural asymmetry of the CST.

Laterality of cerebellar afferent and efferent pathways in a healthy right‐handed population: A diffusion tensor imaging study

“…The CST mainly originates from those cortical areas, which also serve as reciprocal cortical areas of the cerebellum, particularly the areas of origin of the CPCT and the terminal areas of the DRTCT. Several studies have reported that the dominant CST has higher FA and TV values than the non‐dominant CST (Angstmann et al, ; Hasan et al, ; Takao et al, ), which is compatible with our finding of leftward asymmetry of the CST. In the present study, the dominant CPCT revealed lower FA and TV values than the non‐dominant CPCT, with the reverse pattern seen for the CST.…”

“…The CST mainly originates from those cortical areas, which also serve as reciprocal cortical areas of the cerebellum, particularly the areas of origin of the CPCT and the terminal areas of the DRTCT. Several studies have reported that the dominant CST has higher FA and TV values than the non-dominant CST (Angstmann et al, 2016;Hasan et al, 2010;Takao et al, 2011), which is compatible with our finding of leftward asymmetry of the F I G U R E 6 Age-related differences in DTI-derived parameters of the corticospinal tract (CST), cortico-ponto-cerebellar tract (CPCT), and dentato-rubro-thalamo-cortical tract (DRTCT). The 61-80 years age group showed the highest fractional anisotropy (FA) and lowest mean diffusivity CST.…”

The role of diffusion MRI in neuroscience

“…For example, as summarized in Figure , variation in bimanual co‐ordination skills correlates with variation in FA in the body of the corpus callosum, a white matter area that contains transcallosal pathways between primary and supplementary motor areas . Similar effects have been found in a wide range of sensory, motor and cognitive domains including, for example, vision, audition, motor skills and language, literacy, emotion and motivation, visuo‐spatial, memory and executive function, and individual characteristics, such as creativity, musical skills and personality …”

Maturational trajectories of white matter microstructure underlying the right presupplementary motor area reflect individual improvements in motor response cancellation in children and adolescents

“…Participants performed the SST at nine assessments: one through seven, nine and 11. Previous publications on cross-sectional/baseline HUBU data investigated associations between regional white and grey matter microstructure and response inhibition (Madsen et al, 2010), spatial working memory , visuospatial choice reaction time , sustained attention (Klarborg et al, 2013), circle drawing skill (Angstmann et al, 2016) and neuroticism (Madsen et al, 2018).…”