6 research outputs found
Amygdala Volume and Social Anxiety Symptom Severity: A Mutli-method Study
Neuroimaging research has strongly influenced a biologically-based conceptualization of social anxiety, which is the fear of evaluation from others. Functional neuroimaging research has shown consistently a robust association between atypical amygdala activation and social anxiety symptoms. However, there are disparities in the small structural imaging literature on the amygdala and social anxiety. The inconsistent findings may, in part, be a function of differences across studies in the methods used to obtain amygdala volumes. Freesurfer and manual tracings are two common segmentation techniques, and the use of one over the other involves different tradeoffs. The present study directly compared amygdala volumes generated based on Freesurfer’s boundaries to those generated based on manually corrected boundaries, in neurotypical adults with varying levels of social anxiety. Also, it examined whether amygdala volume predicted social anxiety symptom severity. The Liebowitz Social Anxiety Scale – Self-Report version served as a measure of social anxiety. Participants (N = 76) were selected from three larger archival projects. They had social anxiety scores ranging from 0 - 108 (M = 54.59 ± 33.34). The results suggest Freesurfer’s boundaries consistently produced larger amygdala volumes than manually corrected boundaries. However, in neurotypical individuals with and without social anxiety, manual correction did not provide added benefit over the use of Freesurfer with regard to predicting social anxiety symptoms. The present findings strongly suggest that volumetric measurement of the amygdala is not helpful for understanding variability in social anxiety symptom severity and call into question numerous aspects of existing volumetric studies of the neural correlates of social anxiety
Hippocampal Volume and its Association with Verbal Memory in Adult Survivors of Pediatric Brain Tumor
Verbal memory (VM) has been shown to be impacted in brain tumor (BT) survivors, but the nature of VM problems and underlying neuropathology are poorly understood and a long-term outlook is lacking. Our study examined hippocampus volume (HV) and VM in adult survivors of pediatric BT (n=32) and controls (n=48). Results indicate that disruption to a maturing brain in childhood is detectable 17 years (mean) after diagnosis, as HV is significantly lower in survivors compared to controls. Analysis of the VM scores shows that survivors have significantly lower overall immediate recall compared to controls, but learning slope, retention, and recognition are not different across the groups. Survivors’ memory profile indicates that auditory attention and retrieval difficulties could be contributing to their lower immediate recall. For survivors, HV is significantly correlated with delayed free recall but not with other VM indices. Implications of these findings are discussed
Hippocampal Volume and Auditory Attention on a Verbal Memory Task with Adult Survivors of Pediatric Brain Tumor
Objective: We examined the nature of verbal memory deficits and the possible hippocampal underpinnings in long-term adult survivors of childhood brain tumor. Method: 35 survivors (M=24.10±4.93 years at testing; 54% female), on average 15 years post-diagnosis, and 59 typically developing adults (M=22.40±4.35 years, 54% female) participated. Automated FMRIB Software Library (FSL) tools were used to measure hippocampal, putamen, and whole brain volumes. The California Verbal Learning Test – Second Edition (CVLT-II) was used to assess verbal memory. Results: Hippocampal (F(1,91)=4.06, ηp2=.04), putamen (F(1,91)=11.18, ηp2=.11), and whole brain (F(1,92)=18.51, ηp2=.17) volumes were significantly lower for survivors than controls (pr=.62, pr=.09; r=.08), for survivors and controls. Verbal memory indices of auditory attention list span (Trial 1) (F (1,92)=12.70, η2=.12) and final list learning (Trial 5) (F (1,92)=6.01, η2=.06) were significantly lower for survivors (pr=.43, p=.01) with auditory attention, but none of the other CVLT-II indices. Secondary analyses for the effect of treatment factors are presented. Conclusion: 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
Reading Skill in Adult Survivors of Childhood Brain Tumor: A Theory-Based Neurocognitive Model
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 three 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
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