Task control signals in pediatric Tourette syndrome show Task control signals in pediatric Tourette syndrome show evidence of immature and anomalous functional activity evidence of immature and anomalous functional activity

prefrontal cortex. Studies of resting-state functional connectivity MRI (rs-fcMRI), conﬁ rmed the segregation of the regions into two networks (Fair et al . , 2007; Dosenbach et al . , 2008). The combined results from the functional MRI (fMRI) meta-analysis and the subsequent rs-fcMRI analyses (Fair et al . , 2007, 2009; Dosenbach et al . , 2008; Church et al . , 2009) suggest that there are brain regions consistently involved in separable aspects of top-down control over a variety of tasks. One network of regions has positive sustained activity across the duration of a task, suggesting its involvement as a “task-maintenance” network. The other network contains regions showing primarily task initiation signal, suggesting that it may act as a faster, adaptive control network. In principle, should abnormal processing occur at either of these timescales, the result could be unintentional and/or undesired behaviors. a consistent set of regions was found including regions in frontal cortex, parietal cortex, midcingulate, precuneus, anterior cingulate, and bilateral anterior insula regions. The regions consistently active for positive sustained activity included anterior cingulate, bilateral anterior insula, and anterior Tourette Syndrome (TS) is a pediatric movement disorder that may affect control signaling in the brain. Previous work has proposed a dual-networks architecture of control processing involving a task-maintenance network and an adaptive control network (Dosenbach et al . , 2008). A prior resting-state functional connectivity MRI (rs-fcMRI) analysis in TS has revealed functional immaturity in both putative control networks, with “anomalous” correlations (i.e., correlations outside the typical developmental range) limited to the adaptive control network (Church et al . , 2009). The present study used functional MRI (fMRI) to study brain activity related to adaptive control (by studying start-cues signals), and to task-maintenance (by studying signals sustained across a task set). Two hypotheses from the previous rs-fcMRI results were tested. First, adaptive control (i.e., start-cue) activity will be altered in TS, including activity inconsistent with typical development (“anomalous”). Second, group differences found in task-maintenance (i.e., sustained) activity will be consistent with functional immaturity in TS. We examined regions found through a direct comparison of adolescents with and without TS, as well as regions derived from a previous investigation that showed differences between unaffected children and adults. The TS group showed decreased start-cue signal magnitude in regions where start-cue activity is unchanged over typical development, consistent with anomalous adaptive control. The TS group also had higher magnitude sustained signals in frontal cortex regions that overlapped with regions showing differences over typical development, consistent with immature task-maintenance in TS. The results demonstrate task-related fMRI signal differences anticipated by the atypical functional connectivity found previously in adolescents with TS, strengthening the evidence for functional immaturity and anomalous signaling in control networks in adolescents with TS.