Arcuate Fasciculus Abnormalities and Their Relationship with Psychotic Symptoms in Schizophrenia

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

Effects of the neurogranin variant rs12807809 on thalamocortical morphology in schizophrenia

10.1371/journal.pone.0085603PLoS ONE812-POLN

Neurocognitive functioning in schizophrenia and bipolar disorder: Clarifying concepts of diagnostic dichotomy versus continuum

The Kraepelinian dichotomy posits that patients with schizophrenia (SCZ) and bipolar disorder (BD) present as two separate psychotic entities such that they differ in terms of clinical severity including neurocognitive functioning. Our study aimed to specifically compare and contrast the level of neurocognitive functioning between SCZ and BD patients and identify predictors of their poor neurocognitive functioning. We hypothesized that patients with SCZ had a similar level of neurcognitive impairment compared with BD. Forty-nine healthy controls (HC), 72 SCZ and 42 BD patients who were matched for age, gender, and premorbid IQ were administered the Brief Assessment of Cognition battery (BAC). Severity of psychopathology and socio-occupational functioning were assessed for both patients groups. Both BD and SCZ groups demonstrated similar patterns of neurocognitive deficits across several domains (verbal memory, working memory, semantic fluency, processing speed) compared with HC subjects. However, no significant difference was found in neurocognitive functioning between BD and SCZ patients, suggesting that both patient groups suffer the same degree of neurocognitive impairment. Patients with lower level of psychosocial functioning (F(1,112) = 2.661, p = 0.009) and older age (F(1,112) = -2.625, p = 0.010), not diagnosis or doses of psychotropic medications, predicted poorer overall neurocognitive functioning as measured by the lower BAC composite score. Our findings of comparable neurocognitive impairments between SCZ and BD affirm our hypothesis and support less the Kraepelinian concept of dichotomy but more of a continuum of psychotic spectrum conditions. This should urge clinicians to investigate further the underlying neural basis of these neurocognitive deficits, and be attentive to the associated socio-demographic and clinical profile in order to recognize and optimize early the management of the widespread neurocognitive deficits in patients with SCZ and BD

sj-docx-1-hpq-10.1177_13591053231222162 – Supplemental material for Self-compassion and parenting efficacy among mothers who are breast cancer survivors: Implications for psychological distress

Supplemental material, sj-docx-1-hpq-10.1177_13591053231222162 for Self-compassion and parenting efficacy among mothers who are breast cancer survivors: Implications for psychological distress by Carissa Nadia Kuswanto, Lesley Stafford, Penelope Schofield and Jessica Sharp in Journal of Health Psychology</p

Tracking cerebral white matter changes across the lifespan:Insights from diffusion tensor imaging studies

Delineating the normal development of brain white matter (WM) over the human lifespan is crucial to improved understanding of underlying WM pathology in neuropsychiatric and neurological conditions. We review the extant literature concerning diffusion tensor imaging studies of brain WM development in healthy individuals available until October 2012, summarise trends of normal development of human brain WM and suggest possible future research directions. Temporally, brain WM maturation follows a curvilinear pattern with an increase in fractional anisotropy (FA) from newborn to adolescence, decelerating in adulthood till a plateau around mid-adulthood, and a more rapid decrease of FA from old age onwards. Spatially, brain WM tracts develop from central to peripheral regions, with evidence of anterior-to-posterior maturation in commissural and projection fibres. The corpus callosum and fornix develop first and decline earlier, whilst fronto-temporal WM tracts like cingulum and uncinate fasciculus have protracted maturation and decline later. Prefrontal WM is most vulnerable with greater age-related FA reduction compared with posterior WM. Future large scale studies adopting longitudinal design will better clarify human brain WM changes over time. © 2013 Springer-Verlag Wien

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

<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).

<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

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

<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

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

<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