Browsing by keyword "Gyrus Cinguli"
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Anterior cingulate cortex dysfunction in attention-deficit/hyperactivity disorder revealed by fMRI and the Counting StroopBACKGROUND: The anterior cingulate cognitive division (ACcd) plays a central role in attentional processing by: 1) modulating stimulus selection (i.e., focusing attention) and/or 2) mediating response selection. We hypothesized that ACcd dysfunction might therefore contribute to producing core features of attention-deficit/hyperactivity disorder (ADHD), namely inattention and impulsivity. ADHD subjects have indeed shown performance deficits on the Color Stroop, an attentional/cognitive interference task known to recruit the ACcd. Recently, the Counting Stroop, a Stroop-variant specialized for functional magnetic resonance imaging (fMRI), produced ACcd activation in healthy adults. In the present fMRI study, the Counting Stroop was used to examine the functional integrity of the ACcd in ADHD. METHODS: Sixteen unmedicated adults from two groups (8 with ADHD and 8 matched control subjects) performed the Counting Stroop during fMRI. RESULTS: While both groups showed an interference effect, the ADHD group, in contrast to control subjects, failed to activate the ACcd during the Counting Stroop. Direct comparisons showed ACcd activity was significantly higher in the control group. ADHD subjects did activate a frontostriatal-insular network, indicating ACcd hypoactivity was not caused by globally poor neuronal responsiveness. CONCLUSIONS: The data support a hypothesized dysfunction of the ACcd in ADHD.
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Glutamine and glutamate levels in children and adolescents with bipolar disorder: a 4.0-T proton magnetic resonance spectroscopy study of the anterior cingulate cortexOBJECTIVE: The purpose of this study was to use proton magnetic resonance spectroscopy, at 4.0 T, to explore the glutamine and glutamate levels in the anterior cingulate cortex of children and adolescents with bipolar disorder (BPD; medicated and unmedicated) and healthy comparison subjects (HCSs). We hypothesized that unmedicated children with BPD would have reduced glutamine and glutamate levels compared with HCSs and medicated children with BPD. METHOD: Spectra were acquired from the anterior cingulate cortex in 22 children and adolescents with DSM-IV-TR BPD, type 1 (13 female: age 12.6 +/- 4.4 years: 7 of the subjects with BPD were unmedicated at the time of the scan) and 10 HCSs (7 female: age 12.3 +/- 2.5 years). RESULTS: Unmedicated subjects with BPD had significantly lower glutamine levels than HCSs or medicated subjects with BPD. There were no differences in glutamate levels between the three groups. CONCLUSIONS: These results are consistent with there being an abnormality in anterior cingulate cortex glia in untreated children and adolescents with BPD. The results of this pilot study may be important in helping us better understand the pathophysiology of child and adolescent BPD. In addition, this observation may help to develop better and more targeted treatments, in particular those affecting the metabolism of glutamine, perhaps by regulation of glutamine synthetase activity.