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Region-of-interest Analysis (region-of-interest + analysis)
Selected AbstractsPrenatal Alcohol Exposure Affects Frontal,Striatal BOLD Response During Inhibitory ControlALCOHOLISM, Issue 8 2007Susanna L. Fryer Background: Prenatal alcohol exposure can lead to widespread cognitive impairment and behavioral dysregulation, including deficits in attention and response inhibition. This study characterized the neural substrates underlying the disinhibited behavioral profile of individuals with fetal alcohol spectrum disorders (FASD). Methods: Children and adolescents (ages 8,18) with (n=13) and without (n=9) histories of heavy prenatal alcohol exposure underwent functional magnetic resonance imaging while performing a response inhibition (go/no-go) task. Results: Despite similar task performance (mean response latency, performance accuracy, and signal detection), blood oxygen level-dependent (BOLD) response patterns differed by group. Region-of-interest analyses revealed that during portions of the behavioral task that required response inhibition, alcohol-exposed participants showed greater BOLD response across prefrontal cortical regions (including the left medial and right middle frontal gyri), while they showed less right caudate nucleus activation, compared with control participants. Conclusions: These data provide an account of response inhibition-related brain functioning in youth with FASD. Furthermore, results suggest that the frontal,striatal circuitry thought to mediate inhibitory control is sensitive to alcohol teratogenesis. [source] Delay Discounting Behavior and White Matter Microstructure Abnormalities in Youth With a Family History of AlcoholismALCOHOLISM, Issue 9 2010Megan M. Herting Background:, Youth with family history of alcohol abuse have a greater risk of developing an alcohol use disorder (AUD). Brain and behavior differences may underlie this increased vulnerability. The current study examined delay discounting behavior and white matter microstructure in youth at high risk for alcohol abuse, as determined by a family history of alcoholism (FH+), and youth without such family history (FH,). Methods:, Thirty-three healthy youth (FH+ = 15, FH, = 18), ages 11 to 15 years, completed a delay discounting task and underwent diffusion tensor imaging. Tract-based spatial statistics (Smith et al., 2006), as well as follow-up region-of-interest analyses, were performed to compare fractional anisotropy (FA) between FH+ and FH, youth. Results:, FH+ youth showed a trend toward increased discounting behavior and had significantly slower reaction times (RTs) on the delay discounting paradigm compared to FH, youth. Group differences in FA were seen in several white matter tracts. Furthermore, lower FA in the left inferior longitudinal fasciculus and the right optic radiation statistically mediated the relationship between FH status and slower RTs on the delay discounting task. Conclusions:, Youth with a family history of substance abuse have disrupted white matter microstructure, which likely contributes to less efficient cortical processing and may act as an intrinsic risk factor contributing to an increased susceptibility of developing AUD. In addition, FHP youth showed a trend toward greater impulsive decision making, possibly representing an inherent personal characteristic that may facilitate substance use onset and abuse in high-risk youth. [source] Substantial Thalamostriatal Dopaminergic Defect in Unverricht-Lundborg DiseaseEPILEPSIA, Issue 9 2007Miikka Korja Summary:,Purpose: Unverricht-Lundborg disease (ULD) is currently classified as progressive myoclonus epilepsy. Myoclonus, the characteristic symptom in ULD, suggests that dopamine neurotransmission may be involved in the pathophysiology of ULD. Our purpose was to examine brain dopaminergic function in ULD patients. Methods: Four genetically and clinically diagnosed ULD patients and eight healthy controls were scanned with [11C]raclopride-PET. PET images were coregistered to individual 1.5T MR images and region-of-interest analysis was performed for the striatum and thalamus. Standardized uptake values and individual voxel-wise binding potential maps of the patients and controls were also analyzed. Results: ULD patients had markedly higher (31,54%) dopamine D2-like receptor availabilities than healthy controls in both the striatum and the thalamus. The proportionally highest binding potentials were detected in the thalamus. There were no significant differences in the cerebellar uptake of [11C]raclopride in ULD patients versus healthy controls. Voxel-based results were in accordance with the region-of-interest analysis. Conclusions: These results suggest that dopaminergic modulation at the level of the striatum and thalamus could be a crucial factor contributing to the symptoms of ULD. In the light of our data, we propose that ULD with dopamine dysfunction and dyskinetic symptoms shares certain pathophysiological mechanisms with classical movement disorders. Future studies are therefore warranted to study the effect of dopaminergic pharmacotherapy in ULD. [source] Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopiaHUMAN BRAIN MAPPING, Issue 2 2005Janine D. Mendola Abstract Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7,12 years and 18,35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia. Hum Brain Mapp 25:222,236, 2005. © 2005 Wiley-Liss, Inc. [source] Early imaging correlates of subsequent motor recovery after stroke,ANNALS OF NEUROLOGY, Issue 5 2009Randolph S. Marshall MS Objective To determine whether functional magnetic resonance imaging activation obtained in the first few days after stroke correlates with subsequent motor recovery. Methods Twenty-three patients with hemiparesis after first-time stroke were scanned at 2.0 ± 0.9 days while performing a simple motor task. We defined recovery as the change in Fugl,Meyer score from time of scan to approximately 3 months later (90 ± 8 days). We performed three different tests to assess correlations between brain activation and change in Fugl,Meyer score: (1) multivariate (most sensitive to spatially diffuse activation); (2) voxel-wise Statistical Parametric Mapping (most sensitive to focal activation), and (3) primary motor cortex region-of-interest analysis (most sensitive to average activation within this region). All tests controlled for initial stroke severity and lesion volume, as well as other established clinical variables. Results The multivariate test was significant [F (595, 4,934) = 1.93; p < 0.001]. The Statistical Parametric Mapping test detected two small clusters of focal activity located in the ipsilesional postcentral gyrus and cingulate cortex (p < 0.05, corrected). The region-of-interest test was not significant. Interpretation There is a pattern of brain activation present in the first few days after stroke, of which the postcentral gyrus and cingulate cortex are a part, that correlates with subsequent motor recovery. This result suggests that there are recovery processes engaged early after stroke that could provide a target for intervention. Ann Neurol 2009;65:596,602 [source] Cognitive reserve hypothesis: Pittsburgh Compound B and fluorodeoxyglucose positron emission tomography in relation to education in mild Alzheimer's diseaseANNALS OF NEUROLOGY, Issue 1 2008Nina M. Kemppainen MD Objective The reduced risk for Alzheimer's disease (AD) in high-educated individuals has been proposed to reflect brain cognitive reserve, which would provide more efficient compensatory mechanisms against the underlying pathology, and thus delayed clinical expression. Our aim was to find possible differences in brain amyloid ligand 11C-labeled Pittsburgh Compound B ([11C]PIB) uptake and glucose metabolism in high- and low-educated patients with mild AD. Methods Twelve high-educated and 13 low-educated patients with the same degree of cognitive deterioration were studied with PET using [11C]PIB and 18F-fluorodeoxyglucose as ligands. The between-group differences were analyzed with voxel-based statistical method, and quantitative data were obtained with automated region-of-interest analysis. Results High-educated patients showed increased [11C]PIB uptake in the lateral frontal cortex compared with low-educated patients. Moreover, high-educated patients had significantly lower glucose metabolic rate in the temporoparietal cortical regions compared with low-educated patients. Interpretation Our results suggesting more advanced pathological and functional brain changes in high-educated patients with mild AD are in accordance with the brain cognitive reserve hypothesis and point out the importance of development of reliable markers of underlying AD pathology for early AD diagnostics. Ann Neurol 2007 [source] | ||||||||||