Right-left asymmetry in corticospinal tract microstructure and dexterity are uncoupled in late adulthood
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Right-left asymmetry in corticospinal tract microstructure and dexterity are uncoupled in late adulthood. / Demnitz, Naiara; Madsen, Kathrine Skak; Johnsen, Line K.; Kjaer, Michael; Boraxbekk, Carl Johan; Siebner, Hartwig R.
In: NeuroImage, Vol. 240, 118405, 2021.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Right-left asymmetry in corticospinal tract microstructure and dexterity are uncoupled in late adulthood
AU - Demnitz, Naiara
AU - Madsen, Kathrine Skak
AU - Johnsen, Line K.
AU - Kjaer, Michael
AU - Boraxbekk, Carl Johan
AU - Siebner, Hartwig R.
N1 - Publisher Copyright: © 2021
PY - 2021
Y1 - 2021
N2 - Ageing leads to a decline in white matter microstructure and dexterous function of the hand. In adolescents, it has previously been shown that the degree of right-left asymmetry in the corticospinal tract (CST) is linearly related with right-left asymmetry in dexterity. Here, we tested whether this association is also expressed in older adults. Participants completed a simple circle drawing task with their right and left hand as a measure of dexterity and underwent whole-brain diffusion weighted imaging at 3 Tesla (n = 199; aged 60–72 years). Fractional anisotropy and mean diffusivity of right and left CST were extracted from a manually defined region-of-interest. Linear regression analyses were computed to replicate the analyses in adolescents. Frequentist analyses were complemented with a Bayesian analytical framework. Outcome measures were compared with those previously reported in adolescents (aged 11–16 years). Asymmetries in white matter microstructure of the CST were evident and comparable to the degree of lateralisation observed in adolescence. Similarly, asymmetries in dexterity were evident, but to a lesser degree than in adolescents. Unlike in adolescents, we found no evidence of a linear relationship between asymmetries in CST microstructure and dexterity. Complementary Bayesian regression analysis provided moderate evidence in favour of the null hypothesis, pointing towards a lack of association between the structural and functional measures of right-left asymmetry. Our findings are compatible with the notion that, by late adulthood, a diverging impact of age on white matter structure and dexterous hand function dilutes the structure-function relationship between CST microstructure and manual proficiency that has been reported in adolescents.
AB - Ageing leads to a decline in white matter microstructure and dexterous function of the hand. In adolescents, it has previously been shown that the degree of right-left asymmetry in the corticospinal tract (CST) is linearly related with right-left asymmetry in dexterity. Here, we tested whether this association is also expressed in older adults. Participants completed a simple circle drawing task with their right and left hand as a measure of dexterity and underwent whole-brain diffusion weighted imaging at 3 Tesla (n = 199; aged 60–72 years). Fractional anisotropy and mean diffusivity of right and left CST were extracted from a manually defined region-of-interest. Linear regression analyses were computed to replicate the analyses in adolescents. Frequentist analyses were complemented with a Bayesian analytical framework. Outcome measures were compared with those previously reported in adolescents (aged 11–16 years). Asymmetries in white matter microstructure of the CST were evident and comparable to the degree of lateralisation observed in adolescence. Similarly, asymmetries in dexterity were evident, but to a lesser degree than in adolescents. Unlike in adolescents, we found no evidence of a linear relationship between asymmetries in CST microstructure and dexterity. Complementary Bayesian regression analysis provided moderate evidence in favour of the null hypothesis, pointing towards a lack of association between the structural and functional measures of right-left asymmetry. Our findings are compatible with the notion that, by late adulthood, a diverging impact of age on white matter structure and dexterous hand function dilutes the structure-function relationship between CST microstructure and manual proficiency that has been reported in adolescents.
KW - Ageing
KW - Asymmetry
KW - Corticospinal tract
KW - Dexterity
KW - Lateralisation
KW - White matter
U2 - 10.1016/j.neuroimage.2021.118405
DO - 10.1016/j.neuroimage.2021.118405
M3 - Journal article
C2 - 34280529
AN - SCOPUS:85110705107
VL - 240
JO - NeuroImage
JF - NeuroImage
SN - 1053-8119
M1 - 118405
ER -
ID: 275771823