69 research outputs found

    Arcuate Fasciculus Abnormalities and Their Relationship with Psychotic Symptoms in Schizophrenia

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    Disruption of fronto-temporal connections involving the arcuate fasciculus (AF) may underlie language processing anomalies and psychotic features such as auditory hallucinations in schizophrenia. No study to date has specifically investigated abnormalities of white matter integrity at particular loci along the AF as well as its regional lateralization in schizophrenia. We examined white matter changes (fractional anisotropy (FA), axial diffusivity (AD), asymmetry indices) along the whole extent of the AF and their relationship with psychotic symptoms in 32 males with schizophrenia and 44 healthy males. Large deformation diffeomorphic metric mapping and Fiber Assignment Continuous Tracking were employed to characterize FA and AD along the geometric curve of the AF. Our results showed that patients with schizophrenia had lower FA in the frontal aspects of the left AF compared with healthy controls. Greater left FA and AD lateralization in the temporal segment of AF were associated with more severe positive psychotic symptoms such as delusions and hallucinations in patients with schizophrenia. Disruption of white matter integrity of the left frontal AF and accentuation of normal left greater than right asymmetry of FA/AD in the temporal AF further support the notion of aberrant fronto-temporal connectivity in schizophrenia. AF pathology can affect corollary discharge of neural signals from frontal speech/motor initiation areas to suppress activity of auditory cortex that may influence psychotic phenomena such as auditory hallucinations and facilitate elaboration of delusional content

    Lateralization index (LI) profiles of the arcuate fasciculus (AF) in fronto (F)-temporal (T) span and their correlations with clinical scores.

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    <p>On the top row of columns (A, B), the black line denotes the LI profile averaged over healthy controls, while the red line denotes the profile averaged over patients with schizophrenia. The regions in gray denotes the anatomical locations with significant lateralization away from zero at p<0.05 after Bonferroni correction as marked by the dashed line on the bottom row of columns (A, B). On panel (C), the AF superimposed on the 3D lateral view of the brain is colored in yellow for left lateralization and in green for right lateralization. On the top row of columns (D–G), the line denotes correlation profile with clinical scores in patients with schizophrenia. The regions in gray denotes the anatomical locations with significant correlations with clinical scores at p<0.05 after Bonferroni correction as marked by the dashed line on the bottow row of columns (D–G). Arrows on panels (H, I) point to the AF locations with significant correlations shown on panels (D, F, G).</p

    White matter measures of the arcuate fasciculus (AF) using diffusion tensor imaging (DTI).

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    <p>Abbreviations: AD, axial diffusivity; AF, arcuate fasciculus; DTI, diffusion tensor imaging; FA, fractional anisotropy; LI, lateralization indices.</p

    Delineation of the arcuate fasciculus (AF).

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    <p>Panel (A) illustrates the 3D lateral view of the brain in pink and the AF bundle is colored in yellow. The AF extends from the temporal lobe (labeled as “T”) to the frontal lobe (labeled as “F”). Panels (B, C) show the coronal and axial slices of the mean DTI color map, where the ROI boundaries in orange are shown for the AF delineation.</p

    Tract-based analysis of DTI measures along the arcuate fasciculus (AF).

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    <p>On the top row of columns (A–D) the black line denotes the profile averaged over healthy controls, while the red line denotes the profile averaged over patients with schizophrenia. The region in gray denotes the anatomical location with significant group difference at p<0.05 after Bonferroni correction as marked by the dashed line on the bottom row of columns (A–D). The x-axis coordinates on panels (A–D) are normalized by the arc length of the AF. Panel (E) shows the triangle corresponding to the AF loci with a significant difference between healthy controls and patients with schizophrenia.</p

    N-Terminal pro C-Type Natriuretic Peptide (NTproCNP) and myocardial function in ageing.

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    Ageing-related alterations in cardiovascular structure and function are commonly associated with chronic inflammation. A potential blood-based biomarker indicative of a chronic inflammatory state is N-Terminal Pro C-Type Natriuretic Peptide (NTproCNP). We aim to investigate associations between NTproCNP and ageing-related impairments in cardiovascular function. Community-based participants underwent same-day assessment of cardiovascular function and circulating profiles of plasma NTproCNP. Associations between cardiovascular and biomarker profiles were studied in adjusted models including standard covariates. We studied 93 participants (mean age 73 ± 5.3 years, 36 women), of whom 55 (59%) had impaired myocardial relaxation (ratio of peak velocity flow in early diastole E (m/s) to peak velocity flow in late diastole by atrial contraction A (m/s) <0.84). Participants with impaired myocardial relaxation were also found to have lower peak early phase filling velocity (0.6 ± 0.1 vs 0.7 ± 0.1, p < 0.0001) and higher peak atrial phase filling velocity (0.9 ± 0.1 vs 0.7 ± 0.1, p < 0.0001). NTproCNP levelswere significantly lower among participants with impaired myocardial relaxation (16.4% vs 39.5% with NTproCNP ≥ 19, p = 0.012). After multivariable adjustments, NTproCNP was independently associated with impaired myocardial relaxation (OR 2.99, 95%CI 1.12-8.01, p = 0.029). Community elderly adults with myocardial ageing have lower NTproCNP levels compared to those with preserved myocardial function. Given that impaired myocardial relaxation probably represents early changes within the myocardium with ageing, NTproCNP may be useful as an 'upstream' biomarker useful for charting myocardial ageing
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