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### Neuroimaging and electrophysiology studies  See also a review article on recent advances in TS neuroimaging \citep{26543796}| Issues that should be considered when designing MRI neuroimaging studies of children and clinical populations are identified (Greene: "Considerations for MRI study design and implementation in pediatric and clinical populations). This article describes a variety of ways to minimize head movement and to account for movement effects during data analysis.  |  |Head movement effects \citep{25498430}| An important (though frustrating) recent finding was that even very small head movements can cause artifactual findings in _structural_ MRI . Neroimaging scans were performed on 12 healthy adults while they were still or engaged in specific types of movments including nodding, headshaking and a movement that they invented and then repeated during the scan run. Even during scans when subjects remained still, there was an average of 3 mm/s RMSpm (RMS displacement per minute), but it was significantly higher during the motion conditions. In general there was a 1-3% local volume loss for each 1 mm/s RMSpm increase. The greatest thickness reductions were found in the pre- and post-central cortex, in the temporal lobes and pole, and enthorhinal and parahippocampal regions. Increased thickness associated with motion was seen in regions associated with deep sulci such as the medial orbital frontal and lateral frontal areas. Recommendations were made to reduce head motion during scans as much as possible and then control for motion in the statistical analysis, along with using correlational analyses to determine the associations between head motion and the predictors of interest. A more recent article \citep{26654788} described the development of a system for motion tracking and prospective motion correction, and mentions similar systems that are available for other scanner platforms. 
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|  |Tourette syndrome and chronic tic disorder \citep{26531497} |Event-related potentials recordings, during a stimulus-response compatibility task, revealed increased parietal and central activation for both patient groups compared to the control group. The two patient groups were not significantly different from one another.|  |  |Event-related topography and the effect of comorbidities|P300 amplitude in the frontal region was reduced for TS patients with comorbid symptoms compared to control subjects while a medication-naive TS group with no comorbid conditions was similar to the control group. group.|  || Issues that should be considered when designing MRI neuroimaging studies of children and clinical populations are identified (Greene: "Considerations for MRI study design and implementation in pediatric and clinical populations). This article describes a variety of ways to minimize head movement and to account for movement effects during data analysis.  ### Clinical and neuropsychological studies