Neural substrates of self-regulatory control in children and adults with Tourette syndrome.

Objective: To identify the neural substrate of self-regulatory control in children and adults with Tourette syndrome (TS).

Method: We used event-related functional magnetic resonance imaging (fMRI) to study the neural correlates of cognitive self-regulation during the Simon task. Forty-two people from The Tic Disorder Specialty Clinic who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for diagnosis with TS (24 children; 18 adults) were compared with 37 control subjects (19 children; 18 adults).

The risks and benefits of searching for incidental findings in MRI research scans.

We weigh the presumed benefits of routinely searching all research scans for incidental findings (IFs) against its substantial risks, including false-positive and false-negative findings, and the possibility of triggering unnecessary, costly evaluations and perhaps harmful treatments. We argue that routinely searching for IFs may not maximize benefits and minimize risks to participants.

Voxel-wise comparisons of the morphology of diffusion tensors across groups of experimental subjects.

Water molecules in the brain diffuse preferentially along the fiber tracts within white matter that form the anatomical connections across spatially distant brain regions. A diffusion tensor (DT) is a probabilistic ellipsoid composed of three orthogonal vectors, each having a direction and an associated scalar magnitude, that represent the probability of water molecules diffusing in each of those directions. The 3D morphologies of DTs can be compared across groups of subjects to reveal disruptions in structural organization and neuroanatomical connectivity of the brains of persons with various neuropsychiatric illnesses.

Neuroimaging of tic disorders with co-existing attention-deficit/hyperactivity disorder.

Background: Tourette syndrome (TS) and Attention-Deficit/Hyperactivity Disorder (ADHD) are common and debilitating neuropsychiatric illnesses that typically onset in the preschool years. Recently, both conditions have been subject to neuroimaging studies, with the aim of understanding their underlying neurobiological correlates.

Objective: The relation of TS and ADHD is discussed against the background of findings from previous Magnetic Resonance Imaging (MRI) studies.

Correlates of intellectual ability with morphology of the hippocampus and amygdala in healthy adults.

Several prior imaging studies of healthy adults have correlated volumes of the hippocampus and amygdala with measures of general intelligence (IQ), with variable results. In this study, we assessed correlations between volumes of the hippocampus and amygdala and full-scale IQ scores (FSIQ) using a method of image analysis that permits detailed regional mapping of this correlation throughout the surface contour of these brain structures. We delineated the hippocampus and amygdala in high-resolution magnetic resonance images of the brain from 34 healthy individuals.

Hippocampus and amygdala morphology in attention-deficit/hyperactivity disorder.

Context: Limbic structures are implicated in the genesis of attention-deficit/hyperactivity disorder (ADHD) by the presence of mood and cognitive disturbances in affected individuals and by elevated rates of mood disorders in family members of probands with ADHD.

Objective: To study the morphology of the hippocampus and amygdala in children with ADHD.

Design: A cross-sectional case-control study of the hippocampus and amygdala using anatomical magnetic resonance imaging.

Increased number of subcortical hyperintensities on MRI in children and adolescents with Tourette's syndrome, obsessive-compulsive disorder, and attention deficit hyperactivity disorder.

Objective: To investigate whether cerebral hyperintensities on T2-weighted magnetic resonance images (MRI) are associated with childhood neuropsychiatric disorders.

Method: The authors compared the frequency of cortical and subcortical cerebral hyperintensities in 100 children and adolescents with Tourette's syndrome, obsessive-compulsive disorder (OCD), or attention deficit hyperactivity disorder (ADHD) and 32 healthy comparison subjects.

Results: The frequency of cerebral hyperintensities was significantly higher in subjects with Tourette's syndrome, OCD, or ADHD than in healthy comparison subjects; each diagnostic group seemed to contribute to this effect.

A developmental fMRI study of self-regulatory control.

We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of self-regulatory control across development in healthy individuals performing the Stroop interference task. Proper performance of the task requires the engagement of self-regulatory control to inhibit an automatized response (reading) in favor of another, less automatic response (color naming). Functional MRI scans were acquired from a sample of 70 healthy individuals ranging in age from 7 to 57 years.