Abstract: Background: Impulsivity is a characteristic feature of
adolescence. We previously reported in a large (n¼1,896)
sample of 14-year-olds that impulsivity phenotypes were
differentially related to particular brain networks active during
the Stop Signal Task (SST; Whelan et al., 2012). Here, we
investigated how individual differences in these networks at
age 14 relate to inhibitory control networks and impulsivity
phenotypes at age 18.
Methods: Participants completed the SST under fMRI at both
age 14 and age 18. Measures of behavioral impulsivity, substance
misuse and ADHD symptoms were also obtained at
both time points. A factor analysis on regions of interest was
applied to fMRI data. Changes in brain networks were
modelled using a linear mixed effects approach.
Results: Factor analysis with 31 brain regions of interest
(ROIs) revealed remarkably similar networks at age 14 and 18.
All six networks associated with failed inhibition were identical
at age 14 and 18, while successful inhibition trials revealed
minor changes in brain dynamics in a parietal network.
Notably, individual differences in brain activity in a right prefrontal
network at age 14 predicted activity in this network at
age 18 (p<10 ˇ
-10), as did activity in the default mode (p<10 ˇ
and a substantia nigra/subthalamic nucleus network (p<.005).
Changes over the four-year period in the basal ganglia network
during successful and failed inhibition were modulated by the
extent of cigarette use (p¼0.011 and p<0.001, respectively).
Conclusions: Individual differences in task-related brain activity
at age 14 are predictive of activity at age 18 in similar