Volumetric differences between survivors and controls exist for the whole brain and for subcortical structures on average 15 years post-diagnosis. Treatment factors seem to have a unique effect on subcortical structures. Memory differences between survivors and controls are largely contingent upon auditory attention list span. Only hippocampal volume is associated with the auditory attention list span component of verbal memory. These findings are particularly robust for survivors treated with radiation.
Objective: This study investigated the relationship between word reading and white matter (WM) integrity within a neuroanatomical-based reading system comparing adult survivors of childhood brain tumors and controls. It was predicted that the association between WM integrity and word reading would be mediated by processing speed, and this indirect effect would be moderated by group. Method: Thirty-seven adult survivors of childhood brain tumor and typically developing adults participated (age M = 24.19 ± 4.51 years, 62% female). DTI Tractography identified the WM tract for 3 of the reading system connections: inferior fronto-occipital fasciculus (IFOF), arcuate fasciculus (AF), and parietotemporal-occipitotemporal connection (PT-OT). Results: Fractional anisotropy values (FA) of the PT-OT tract were significantly correlated with word reading in survivors and controls (r = .45, .58, respectively; p < .05) and IFOF values were associated with reading in survivors only (r = .59, p < .01). Further, the moderated mediated model was significant for PT-OT and IFOF, such that the indirect effect of processing speed was only present for survivors (CI: PT-OT: 2.90, 28.41, IFOF: 2.92, 40.17). Conclusion: Results suggest the tracts emerging from the occipitotemporal area are a critical component of the reading system in adults. The finding that processing speed was the mechanism by which WM was associated with reading in survivors is in alignment with the developmental cascade model. Current findings bolster the existing theory-based models of reading using innovative diffusion tensor imaging and moderated mediation statistical neurodevelopmental model, establishing the role of processing speed and specific WM pathway integrity in word reading skill.
The amygdala factors prominently in neurobiological models of social anxiety (SA), yet amygdala volume findings regarding SA have been inconsistent and largely focused on case-control characterization. One source of discrepant findings could be variability in volumetric techniques. Therefore, we compared amygdala volumes derived via an automated technique (Freesurfer) against a manually corrected approach, also involving Freesurfer. Additionally, we tested whether the relationship between volume and SA symptom severity would differ across volumetric techniques. We pooled participants (n = 76) from archival studies. SA severity was assessed with the Liebowitz Social Anxiety Scale; scores ranged from non-clinical to clinical levels. Freesurfer produced significantly larger amygdalar volumes for participants with poor image quality. Even after excluding such participants, paired sample t-tests showed Freesurfer's boundaries produced significantly larger amygdalar volumes than manually corrected ones, bilaterally. Yet, intra-class correlation coefficients between the two methods were high, which suggests that Freesurfer's over-*
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