Page 239 - Like me, or else... - Michelle Achterberg
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                                Fronto-striatal connectivity predicts patience
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 Global white matter effects
In order to test for the specificity of the fronto-striatal tract in predicting discounting behavior, we performed a similar analysis with global FA and MD (i.e., all white matter connections excluding the connections marked as fronto- striatal tract). Longitudinal analyses revealed that age-related change in global white matter integrity (FA and MD) was also best explained by a cubic age-model (FA: age1: β=0.225, p<.001; age2: β=-0.095, p<.001; age3: β=0.047, p=.004; MD: age1: β=-0.00010, p<.001; age2: β=0.00005, p=.018; age3: β=-0.00007, p=.001). Age-related change between 8 and 18 years only was –similar to the fronto-striatal tracts- best explained by a quadratic age-model (FA: age1: β=0.227, p<.001; age2: β=-0.041, p<.001; age3: β=0.017, p=.073; MD: age1: β=0.00005, p=.063; age2: β=0.00009, p<.001; age3: β=-0.00002, p=.123). Importantly, the linear regression analysis showed that global FA (β=.059, p=.539) and MD (β=.060, p=.802) did not predict future discounting behavior.
Table 3. Linear regression predicting delay of gratification skills at T2 using delay of gratification skills (AUC normalized), age, FA, and MD at T1.
                  Constant
T1 AUC (normalized) T1 Age
T1 FA of the FS-tract T1 MD of the FS-tract
B SE β p -.996 .772 .199
.463 .059
.003 .005 1.970 .922 726.143 766.871
.504 .000 .048 .473 .158 .034 .064 .345
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