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Posterior Cingulate (posterior + cingulate)

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Medical Sciences70%

Terms modified by Posterior Cingulate

  • posterior cingulate cortex
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    Selected Abstracts

    Structural MRI biomarkers for preclinical and mild Alzheimer's disease,

    HUMAN BRAIN MAPPING, Issue 10 2009
    Christine Fennema-Notestine
    Abstract Noninvasive MRI biomarkers for Alzheimer's disease (AD) may enable earlier clinical diagnosis and the monitoring of therapeutic effectiveness. To assess potential neuroimaging biomarkers, the Alzheimer's Disease Neuroimaging Initiative is following normal controls (NC) and individuals with mild cognitive impairment (MCI) or AD. We applied high-throughput image analyses procedures to these data to demonstrate the feasibility of detecting subtle structural changes in prodromal AD. Raw DICOM scans (139 NC, 175 MCI, and 84 AD) were downloaded for analysis. Volumetric segmentation and cortical surface reconstruction produced continuous cortical surface maps and region-of-interest (ROI) measures. The MCI cohort was subdivided into single- (SMCI) and multiple-domain MCI (MMCI) based on neuropsychological performance. Repeated measures analyses of covariance were used to examine group and hemispheric effects while controlling for age, sex, and, for volumetric measures, intracranial vault. ROI analyses showed group differences for ventricular, temporal, posterior and rostral anterior cingulate, posterior parietal, and frontal regions. SMCI and NC differed within temporal, rostral posterior cingulate, inferior parietal, precuneus, and caudal midfrontal regions. With MMCI and AD, greater differences were evident in these regions and additional frontal and retrosplenial cortices; evidence for non-AD pathology in MMCI also was suggested. Mesial temporal right-dominant asymmetries were evident and did not interact with diagnosis. Our findings demonstrate that high-throughput methods provide numerous measures to detect subtle effects of prodromal AD, suggesting early and later stages of the preclinical state in this cross-sectional sample. These methods will enable a more complete longitudinal characterization and allow us to identify changes that are predictive of conversion to AD. Hum Brain Mapp 2009. © 2009 Wiley-Liss, Inc. [source]

    Receptor architecture of human cingulate cortex: Evaluation of the four-region neurobiological model

    HUMAN BRAIN MAPPING, Issue 8 2009
    Nicola Palomero-Gallagher
    Abstract The structural and functional organization of the human cingulate cortex is an ongoing focus; however, human imaging studies continue to use the century-old Brodmann concept of a two region cingulate cortex. Recently, a four-region neurobiological model was proposed based on structural, circuitry, and functional imaging observations. It encompasses the anterior cingulate, midcingulate, posterior cingulate, and retrosplenial cortices (ACC, MCC, PCC, and RSC, respectively). For the first time, this study performs multireceptor autoradiography of 15 neurotransmitter receptor ligands and multivariate statistics on human whole brain postmortem samples covering the entire cingulate cortex. We evaluated the validity of Brodmann's duality concept and of the four-region model using a hierarchical clustering analysis of receptor binding according to the degree of similarity of each area's receptor architecture. We could not find support for Brodmann's dual cingulate concept, because the anterior part of his area 24 has significantly higher AMPA, kainate, GABAB, benzodiazepine, and M3 but lower NMDA and GABAA binding site densities than the posterior part. The hierarchical clustering analysis distinguished ACC, MCC, PCC, and RSC as independent regions. The ACC has highest AMPA, kainate, ,2, 5-HT1A, and D1 but lowest GABAA densities. The MCC has lowest AMPA, kainate, ,2, and D1 densities. Area 25 in ACC is similar in receptor-architecture to MCC, particularly the NMDA, GABAA, GABAB, and M2 receptors. The PCC and RSC differ in the higher M1 and ,1 but lower M3 densities of PCC. Thus, multireceptor autoradiography supports the four-region neurobiological model of the cingulate cortex. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source]

    Alcohol intoxication effects on visual perception: An fMRI study

    HUMAN BRAIN MAPPING, Issue 1 2004
    Vince D. Calhoun
    Abstract We examined the effects of two doses of alcohol (EtOH) on functional magnetic resonance imaging (fMRI) activation during a visual perception task. The Motor-Free Visual Perception Test,Revised (MVPT-R) provides measures of overall visual perceptual processing ability. It incorporates different cognitive elements including visual discrimination, spatial relationships, and mental rotation. We used the MVPT-R to study brain activation patterns in healthy controls (1) sober, and (2) at two doses of alcohol intoxication with event-related fMRI. The fMRI data were analyzed using a general linear model approach based upon a model of the time course and a hemodynamic response estimate. Additionally, a correlation analysis was performed to examine dose-dependent amplitude changes. With regard to alcohol-free task-related brain activation, we replicate our previous finding in which SPM group analysis revealed robust activation in visual and visual association areas, frontal eye field (FEF)/dorsolateral prefrontal cortex (DLPFC), and the supplemental motor area (SMA). Consistent with a previous study of EtOH and visual stimulation, EtOH resulted in a dose-dependent decrease in activation amplitude over much of the visual perception network and in a decrease in the maximum contrast-to-noise ratio (in the lingual gyrus). Despite only modest behavior changes (in the expected direction), significant dose-dependent activation increases were observed in insula, DLPFC, and precentral regions, whereas dose-dependent activation decreases were observed in anterior and posterior cingulate, precuneus, and middle frontal areas. Some areas (FEF/DLPFC/SMA) became more diffusely activated (i.e., increased in spatial extent) at the higher dose. Alcohol, thus, appears to have both global and local effects upon the neural correlates of the MVPT-R task, some of which are dose dependent. Hum. Brain Mapping 21:15,26, 2004. © 2003 Wiley-Liss, Inc. [source]

    Coronary heart disease is associated with regional grey matter volume loss: implications for cognitive function and behaviour

    INTERNAL MEDICINE JOURNAL, Issue 7 2008
    O. P. Almeida
    Abstract Coronary heart disease (CHD) has been associated with impaired cognition, but the mechanisms underlying these changes remain unclear. We designed this study to determine whether adults with CHD show regional brain losses of grey matter volume relative to controls. We used statistical parametric mapping (SPM5) to determine regional changes in grey matter volume of T1 -weighted magnetic resonance images of 11 adults with prior history of myocardial infarction relative to seven healthy controls. All analyses were adjusted for total grey and white matter volume, age, sex and handedness. CHD participants showed a loss of grey matter volume in the left medial frontal lobe (including the cingulate), precentral and postcentral cortex, right temporal lobe and left middle temporal gyrus, and left precuneus and posterior cingulate. CHD is associated with loss of grey matter in various brain regions, including some that play a significant role in cognitive function and behaviour. The underlying causes of these regional brain changes remain to be determined. [source]

    Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers.

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2004
    A positron emission tomographic study
    Background:, We tested the hypothesis that escalating drug concentrations of sevoflurane are associated with a significant decline of cerebral blood flow in regions subserving conscious brain activity, including specifically the thalamus. Methods:, Nine healthy human volunteers received three escalating doses using 0.4%, 0.7% and 2.0% end-tidal sevoflurane inhalation. During baseline and each of the three levels of anaesthesia one PET scan was performed after injection of . Cardiovascular and respiratory parameters were monitored and electroencephalography and bispectral index (BIS) were registered. Results:, Sevoflurane decreased the BIS values dose-dependently. No significant change in global cerebral blood flow (CBF) was observed. Increased regional CBF (rCBF) in the anterior cingulate (17,21%) and decreased rCBF in the cerebellum (18,35%) were identified at all three levels of sedation compared to baseline. Comparison between adjacent levels sevoflurane initially (0 vs. 0.2 MAC) decreased rCBF significantly in the inferior temporal cortex and the lingual gyrus. At the next level (0.2 MAC vs. 0.4 MAC) rCBF was increased in the middle temporal cortex and in the lingual gyrus, and decreased in the thalamus. At the last level (0.4 MAC vs. 1 MAC) the rCBF was increased in the insula and decreased in the posterior cingulate, the lingual gyrus, precuneus and in the frontal cortex. Conclusion:, At sevoflurane concentrations at 0.7% and 2.0% a significant decrease in relative rCBF was detected in the thalamus. Interestingly, some of the most profound changes in rCBF were observed in structures related to pain processing (anterior cingulate and insula). [source]

    Alzheimer's disease versus dementia with Lewy bodies: Cerebral metabolic distinction with autopsy confirmation

    ANNALS OF NEUROLOGY, Issue 3 2001
    Satoshi Minoshima MD
    Seeking antemortem markers to distinguish Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), we examined brain glucose metabolism of DLB and AD. Eleven DLB patients (7 Lewy body variant of AD [LBVAD] and 4 pure diffuse Lewy body disease [DLBD]) who had antemortem position emission tomography imaging and autopsy confirmation were compared to 10 autopsy-confirmed pure AD patients. In addition, 53 patients with clinically-diagnosed probable AD, 13 of whom later fulfilled clinical diagnoses of DLB, were examined. Autopsy-confirmed AD and DLB patients showed significant metabolic reductions involving parietotemporal association, posterior cingulate, and frontal association cortices. Only DLB patients showed significant metabolic reductions in the occipital cortex, particularly in the primary visual cortex (LBVAD ,23% and DLBD ,29% vs AD ,8%), which distinguished DLB versus AD with 90% sensitivity and 80% specificity. Multivariate analysis revealed that occipital metabolic changes in DLB were independent from those in the adjacent parietotemporal cortices. Analysis of clinically-diagnosed probable AD patients showed a significantly higher frequency of primary visual metabolic reduction among patients who fulfilled later clinical criteria for DLB. In these patients, occipital hypometabolism preceded some clinical features of DLB. Occipital hypometabolism is a potential antemortem marker to distinguish DLB versus AD. [source]

    Abnormal cerebellum density in victims of rape with post-traumatic stress disorder: Voxel-based analysis of magnetic resonance imaging investigation

    ASIA-PACIFIC PSYCHIATRY, Issue 3 2010
    Shuang-Ge Sui MD MBA
    Abstract Introduction: Based on early studies of non-motor function in the cerebellum and dysfunction in the cerebellum of post-traumatic stress disorder (PTSD) patients, we presumed that the cerebellum was involved in the neuropathology of cognitive and emotional processing of PTSD patients, while the density of some sub-areas of the cerebellum of PTSD patients was most likely abnormal. Methods: Eleven female victims of rape with PTSD and 12 age-matched female normal controls received 1.5 T 3D magnetic resonance imaging (MRI) scan. The scans were then analyzed using the voxel-based morphometry 2 (VBM2) toolbox. Results: Victims of rape with PTSD showed increased cerebellum density on the left side compared with normal controls (P<0.001), especially in the pyramis (x=,9, y=,72, z=,36; k=519; t=4.70), uvula (x=,4, y=,66, z=,35; k=256; t=4.02), declive (x=,6, y=,69, z=,30; k=213; t=3.84) and nodule (x=,4, y=,63, z=,31; k=147; t=3.93). In addition, compared with normal controls, the PTSD group showed significant differences in gray matter density of other brain areas, including the frontal lobe, parietal lobe, occipital lobe (P<0.001), insula, posterior cingulate, amygdala and hippocampus (P<0.005). Discussion: These finding suggest that the cerebellum may be involved in the neuropathology and functional compensation in the neurocircuitry of PTSD. [source]

    A magnetic resonance imaging study of mood stabilizer- and neuroleptic-naïve first-episode mania

    BIPOLAR DISORDERS, Issue 7 2007
    Lakshmi N Yatham
    Objectives:, Patients with bipolar disorder have changes in brain structures but it is unclear if these are present at disease onset and thus predispose subjects to develop the disorder, or whether they develop during the course of the disorder, either due to the effects of multiple episodes or as a consequence of treatment with psychotropic agents. Studies in first-episode (FE) manic patients have the potential to provide answers to these questions. Methods:, Voxel-based morphometry (VBM) was used to assess magnetic resonance imaging scans of 15 FE manic patients and 15 matched healthy controls. Results:, Using a priori defined statistical criteria, no significant differences in brain structures were noted between the two groups. However, there was approximately a 6% reduction in left anterior cingulate, left precuneus and right posterior cingulate volume in FE patients and these reductions were significant (p , 0.002) at uncorrected levels. Conclusions:, First-episode manic patients have reductions in left anterior, right posterior cingulate as well as left precuneus volumes, but these reductions are smaller and likely worsen with further mood episodes in bipolar patients. [source]

    Rey Visual Design Learning Test performance correlates with white matter structure

    ACTA NEUROPSYCHIATRICA, Issue 2 2009
    Stefan Begré
    Objective:, Studies exploring relation of visual memory to white matter are extensively lacking. The Rey Visual Design Learning Test (RVDLT) is an elementary motion, colour and word independent visual memory test. It avoids a significant contribution from as many additional higher order visual brain functions as possible to visual performance, such as three-dimensional, colour, motion or word-dependent brain operations. Based on previous results, we hypothesised that test performance would be related with white matter of dorsal hippocampal commissure, corpus callosum, posterior cingulate, superior longitudinal fascicle and internal capsule. Methods:, In 14 healthy subjects, we measured intervoxel coherence (IC) by diffusion tensor imaging as an indication of connectivity and visual memory performance measured by the RVDLT. IC considers the orientation of the adjacent voxels and has a better signal-to-noise ratio than the commonly used fractional anisotropy index. Results:, Using voxelwise linear regression analyses of the IC values, we found a significant and direct relationship between 11 clusters and visual memory test performance. The fact that memory performance correlated with white matter structure in left and right dorsal hippocampal commissure, left and right posterior cingulate, right callosal splenium, left and right superior longitudinal fascicle, right medial orbitofrontal region, left anterior cingulate, and left and right anterior limb of internal capsule emphasises our hypothesis. Conclusion:, Our observations in healthy subjects suggest that individual differences in brain function related to the performance of a task of higher cognitive demands might partially be associated with structural variation of white matter regions. [source]