Neuroimaging of inhibitory control areas in children with attention deficit hyperactivity disorder who were treatment naive or in long-term treatment.
ABSTRACT Difficulty with response inhibition is a cardinal symptom of attention deficit hyperactivity disorder (ADHD), combined type. Prefrontal and cingulate brain regions are known to be involved in inhibitory control. Event-related functional magnetic resonance imaging (fMRI) might establish if these regions differ in their activity in ADHD children relative to healthy comparison subjects.
Fifteen healthy comparison subjects and 17 children with ADHD, combined type, completed fMRI studies while performing the Stop Signal Task. Eight ADHD subjects were treatment naive; the remainder had a history of long-term treatment with stimulants, but they were medication free at the time of the fMRI. No subject had a learning disorder or a comorbid psychiatric condition (other than oppositional defiant disorder in the ADHD subjects).
Both the ADHD and comparison subjects activated the right dorsolateral prefrontal cortex on "stop" trials relative to "go" trials; this increase was greater in ADHD subjects. When inhibition was unsuccessful (relative to successful inhibition), healthy comparison subjects strongly activated the anterior cingulate cortex and the left ventrolateral prefrontal cortex. In contrast, the ADHD subjects did not show these differences. Activations in treatment-naive and ADHD subjects treated in the long term did not differ significantly in any brain regions.
In relation to comparison subjects, ADHD subjects failed to activate the anterior cingulate cortex and the left ventrolateral prefrontal cortex after unsuccessful inhibition. These findings appear in treatment-naive ADHD individuals and are unlikely to be an artifact of long-term treatment with stimulants or of abrupt termination of stimulants before imaging.
SourceAvailable from: Hasan Ayaz
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ABSTRACT: Introduction To the best of our knowledge, this is the first case report of successful treatment for bipolar II disorder using a combined ketamine and transcranial magnetic stimulation treatment. Case presentation A 43-year-old Caucasian unemployed man presented to us with treatment-resistant bipolar II disorder, currently in a mixed state. A psychometric assessment and brain single-photon emission computer tomography scan were conducted at baseline. His psychometric assessment revealed severe depressive and manic symptoms that were consistent with bipolar II disorder. Findings from a brain single-photon emission computer tomography scan converged with those from his psychometric assessment. The combined ketamine and transcranial magnetic stimulation treatment was administered a total of 24 times over five months, with his ketamine dosage increased from 50mg at the first treatment to 600mg by the last. Starting after the second treatment, he reported substantial improvements in his symptoms. A follow-up psychometric assessment and brain single-photon emission computer tomography scan five months later revealed substantial blood flow increases in the previously deficient areas. Conclusions We provide preliminary evidence for a treatment method that magnifies the therapeutic benefits of infused ketamine along with transcranial magnetic stimulation. We postulate that this may be based on an interaction at the level of the relevant cortico-thalamo-cortical circuit(s).Journal of Medical Case Reports 03/2015; 9. DOI:10.1186/s13256-015-0520-0
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ABSTRACT: Attention-deficit/hyperactivity disorder (ADHD) is a common disabling psychiatric disorder associated with consistent deficits in error processing, inhibition and regionally decreased grey matter volumes. The diagnosis is based on clinical presentation, interviews and questionnaires, which are to some degree subjective and would benefit from verification through biomarkers. Here, pattern recognition of multiple discriminative functional and structural brain patterns was applied to classify adolescents with ADHD and controls. Functional activation features in a Flanker/NoGo task probing error processing and inhibition along with structural magnetic resonance imaging data served to predict group membership using support vector machines (SVMs). The SVM pattern recognition algorithm correctly classified 77.78 % of the subjects with a sensitivity and specificity of 77.78 % based on error processing. Predictive regions for controls were mainly detected in core areas for error processing and attention such as the medial and dorsolateral frontal areas reflecting deficient processing in ADHD (Hart et al., in Hum Brain Mapp 35:3083-3094, 2014), and overlapped with decreased activations in patients in conventional group comparisons. Regions more predictive for ADHD patients were identified in the posterior cingulate, temporal and occipital cortex. Interestingly despite pronounced univariate group differences in inhibition-related activation and grey matter volumes the corresponding classifiers failed or only yielded a poor discrimination. The present study corroborates the potential of task-related brain activation for classification shown in previous studies. It remains to be clarified whether error processing, which performed best here, also contributes to the discrimination of useful dimensions and subtypes, different psychiatric disorders, and prediction of treatment success across studies and sites.European Child & Adolescent Psychiatry 01/2015; DOI:10.1007/s00787-015-0678-4 · 3.55 Impact Factor