Search results for "Posterior cingulate"
showing 10 items of 11 documents
Relationship Between Body Mass Index, ApoE4 Status, and PET-Based Amyloid and Neurodegeneration Markers in Amyloid-Positive Subjects with Normal Cogn…
2018
Body weight loss in late-life is known to occur at a very early stage of Alzheimer's disease (AD). Apolipoprotein E4 (ApoE4) represents a major genetic risk factor for AD and is linked to an increased cortical amyloid-β (Aβ) accumulation. Since the relationship between body weight, ApoE4, and AD pathology is poorly investigated, we aimed to evaluate whether ApoE4 allelic status modifies the association of body mass index (BMI) with markers of AD pathology. A total of 368 Aβ-positive cognitively healthy or mild cognitive impaired subjects had undergone [18F]-AV45-PET, [18F]-FDG-PET, and T1w-MRI examinations. Composite cortical [18F]-AV45 uptake and [18F]-FDG uptake in posterior cingulate cor…
Metabolic and structural connectivity within the default mode network relates to working memory performance in young healthy adults.
2012
Abstract Studies of functional connectivity suggest that the default mode network (DMN) might be relevant for cognitive functions. Here, we examined metabolic and structural connectivity between major DMN nodes, the posterior cingulate (PCC) and medial prefrontal cortex (MPFC), in relation to normal working memory (WM). DMN was captured using independent component analysis of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) data from 35 young healthy adults (27.1 ± 5.1 years). Metabolic connectivity, a correlation between FDG uptake in PCC and MPFC, was examined in groups of subjects with (relative to median) low (n = 18) and high (n = 17) performance on digit span backward te…
Tract-specific white matter structural disruption in patients with bipolar disorder
2011
Benedetti F, Absinta M, Rocca MA, Radaelli D, Poletti S, Bernasconi A, Dallaspezia S, Pagani E, Falini A, Copetti M, Colombo C, Comi G, Smeraldi E, Filippi M. Tract-specific white matter structural disruption in patients with bipolar disorder. Bipolar Disord 2011: 13: 414–424. © 2011 The Authors. Journal compilation © 2011 John Wiley & Sons A/S. Objectives: A growing body of evidence suggests that, independent of localized brain lesions, mood disorders can be associated with dysfunction of brain networks involved in the modulation of emotional and cognitive behavior. We used diffusion tensor (DT) tractography to quantify the presence and extent of structural injury to the connections betwe…
Color-coded diffusion-tensor-imaging of posterior cingulate fiber tracts in mild cognitive impairment.
2005
Abstract Different processes like microvascular dysfunction, free radical toxicity, β-amyloid deposits, and Wallerian degeneration can cause functionally relevant disturbances of cerebral neuronal networks by myelin degeneration. Color-coded diffusion-tensor-imaging (ccDTI) allows the structural identification and quantification of myelinated fiber tracts. Particularly, posterior cingulate fiber tracts, which are regarded as important neuronal substrates of the network representing memory processing can be localized only imprecisely by conventional magnetic resonance imaging techniques. The posterior cingulate bundles were assessed by ccDTI in 17 patients with amnestic mild cognitive impair…
Diaschisis-Like Association of Hippocampal Atrophy and Posterior Cingulate Cortex Hypometabolism in Cognitively Normal Elderly Depends on Impaired In…
2017
Hippocampal atrophy and hypometabolism of the posterior cingulate cortex (PCC), early markers of Alzheimer's disease (AD), have been shown to be associated in late mild cognitive impairment and early AD via atrophy of connecting cingulum fibers. Recently, a direct association of hippocampal atrophy and PCC hypometabolism has been shown in cognitively normal elderly. We aimed to investigate if this association might be modulated by partly non-hippocampogenic alterations of parahippocampal cingulum (PHC) integrity. 45 cognitively healthy elderly aged 59 to 89 years were included from the Alzheimer's Disease Neuroimaging Initiative. Hippocampal volumes and PCC glucose metabolism were measured …
Brain changes in long-term zen meditators using proton magnetic resonance spectroscopy and diffusion tensor imaging: a controlled study.
2013
Introduction: This work aimed to determine whether 1 H magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are correlated with years of meditation and psychological variables in long-term Zen meditators compared to healthy non-meditator controls. Materials and Methods: Design. Controlled, cross-sectional study. Sample. Meditators were recruited from a Zen Buddhist monastery. The control group was recruited from hospital staff. Meditators were administered questionnaires on anxiety, depression, cognitive impairment and mindfulness. 1 H-MRS (1.5 T) of the brain was carried out by exploring four areas: bot…
Feeling addressed! The neural processing of social communicative cues in patients with major depression
2020
Abstract The feeling of being addressed is the first step in a complex processing stream enabling successful social communication. Social impairments are a relevant characteristic of patients with major depressive disorder (MDD). Here, we investigated a mechanism which—if impaired—might contribute to withdrawal or isolation in MDD, namely, the neural processing of social cues such as body orientation and gesture. During funtional magnetic resonance imaging (fMRI) data acquisition, 33 patients with MDD and 43 healthy control subjects watched video clips of a speaking actor: one version with a gesture accompanying the speech and one without gesture. Videos were filmed simultaneously from two …
Association between Cognitive Performance and Cortical Glucose Metabolism in Patients with Mild Alzheimer’s Disease
2004
<i>Background:</i> Neuronal and synaptic function in Alzheimer’s disease (AD) is measured in vivo by glucose metabolism using positron emission tomography (PET). <i>Objective:</i> We hypothesized that neuronal activation as measured by PET is a more sensitive index of neuronal dysfunction than activity during rest. We investigated if the correlations between dementia severity as measured with the Mini Mental State Examination (MMSE) and glucose metabolism are an artifact of brain atrophy. <i>Method:</i> Glucose metabolism was measured using [<sup>18</sup>F]fluorodeoxyglucose PET during rest and activation due to audiovisual stimulation in 13 m…
Cognitive impairment: classification by 1H magnetic resonance spectroscopy.
2004
1H magnetic resonance spectroscopy (MRS) allows accurate and non-invasive in vivo metabolic study, and is a useful tool for the diagnosis of different forms of dementias. Cognitive impairment pathologies have been almost exclusively studied with MRS by comparison with healthy without a global comparison amongst Alzheimer disease (AD), vascular dementia, mild cognitive impairment (MCI) and major depression patients with cognitive impairment. Whereas decrease of N-acetylaspartate (NAA) and increase myo-Inositol (mI) at different brain locations by 1H MRS are common features of AD, Choline (Cho) alterations have been inconclusive. In our study, 64 patients with cognitive impairment were evalua…
Brain and behavioral alterations in subjects with social anxiety dominated by empathic embarrassment
2020
Significance People are increasingly affected by social anxiety that includes emotional hypersensitivity and inaccurate interpretation of social encounters, and varies markedly in its subjective manifestations. We searched for insights into the underlying neurocognitive mechanisms of Taijin-kyofusho (TKS), a specific subtype of social-anxiety disorder common in East Asia and dominated by empathic or other-oriented embarrassment. We found TKS to be characterized by enhanced affective and reduced cognitive empathy. Moreover, analysis of functional MRI data—collected while subjects viewed videos of badly singing people—revealed disruption of the cognitive–empathy network, possibly obstructing …