The aim of this study was to investigate the morphology of the corpus callosum (CC) in Tourette syndrome (TS) and attention deficit hyperactivity disorder (ADHD) to determine whether these conditions affect distinct regional differences. Seventy-seven children and adolescents, aged 6 to 16 years, comprised the four research groups--16 patients with TS, 21 patients with TS plus ADHD, 13 patients with ADHD, and 27 unaffected control subjects. A semiautomated, computer-assisted procedure was used to measure the total area, five subregions, centerline length, perimeter, and bending angle of the CC. MRI data were analyzed using several statistical methods, primarily two-tailed analysis of variance to test the effects of TS and ADHD status, while controlling for the influence of age, gender, and total intracranial area (an estimate of brain size). TS was associated with significant increases in the area of four of five subdivisions, the total area, and the perimeter of the CC. ADHD was associated with a significant decrease in the area of the rostral body. There were no interactions between TS and ADHD factors. These findings suggest that the area of the CC is larger in children with TS, and that this difference is independent of age, handedness, intracranial area, and the diagnosis of ADHD. Our findings support hypotheses that the neurobiologic mechanisms in TS and ADHD involve frontal/subcortical circuits.

Network analysis has been increasingly applied in an effort to understand complex interactions among symptoms in posttraumatic stress disorder (PTSD). Although methods that initially focused on identifying central symptoms in cross‐sectional networks have been extended to longitudinal data that can reveal the relative roles of acute symptoms in the emergence of the PTSD syndrome, the association between network metrics and symptom change during treatment have yet to be explored in PTSD. To address this gap, we estimated pretreatment PTSD symptom networks in a sample of patients from a multisite clinical trial for women with full or subthreshold PTSD and substance use. We tested the hypothesis that node metrics calculated in the pretreatment network would be predictive of the strength of the association between a symptom's change and the change in the severity of all other symptoms through the course of treatment. A symptom node's strength and predictability in the pretreatment network were each strongly correlated with the association between that symptom's change and overall change across the symptom network, r(15) = .79, p < .001 and r(15) = .75, p < .001, respectively, whereas a symptom's mean severity at pretreatment was not, r(15) = .27, p = .292. These findings suggest that a node's centrality prior to treatment engagement is a predictor of its association with overall symptom change throughout the treatment process.

Previous research associates smaller hippocampal volume with posttraumatic stress disorder (PTSD). It is unclear, however, whether treatment affects hippocampal volume or vice versa. Seventy-six subjects, 40 PTSD patients and 36 matched trauma-exposed healthy resilient controls, underwent clinical assessments and magnetic resonance imaging (MRI) at baseline, and 10 weeks later, during which PTSD patients completed ten weeks of Prolonged Exposure (PE) treatment. The resilient controls and treatment responders (n=23) had greater baseline hippocampal volume than treatment non-responders (n=17) (p=0.012 and p=0.050, respectively), perhaps due to more robust fear-extinction capacity in both the initial phase after exposure to trauma and during treatment.

Background Brain structures underlying posttraumatic stress disorder (PTSD) have been a focus of imaging studies, but associations between treatment outcome and alterations in brain structures remain largely unexamined. We longitudinally examined the relation of structural changes in the rostral anterior cingulate cortex (rACC), a previously identified key region in the PTSD fear network, to outcome of Prolonged Exposure (PE) treatment. Method The sample included 78 adults (53 women): 41 patients with PTSD and 37 trauma-exposed healthy volunteers (TE-HCs). Patients underwent a 10-week course of PE treatment and completed pre-and post-treatment assessments and magnetic resonance imaging (MRI) structural scans. TE-HCs also underwent assessment and MRI at baseline and 10 weeks later. PE remitters (n =11), non-remitters (n= 14), and TE-HCs, were compared at baseline on demographic and clinical characteristics and ACC structure. Remitters, non-remitters, and TE-HCs were compared for pre- to post-treatment clinical and structural ACC change, controlling for potential confounding variables. Results There were no baseline differences in structure between PTSD and TE-HCs or remitters and non-remitters. Following treatment, PTSD remitters exhibited cortical thinning and volume decrease in the left rACC compared with PTSD non-remitters and TE-HCs. Conclusions These results, while in need of replication, suggest that PE treatment for PTSD, by extinguishing maladaptive trauma associations, may promote synaptic plasticity and structure change in rACC. Future research should explore possible underlying mechanisms.

Biased attention to social threat has been implicated in social anxiety disorder. Modifying visual attention during exposure therapy offers a direct test of this mechanism. We developed and tested a brief virtual reality exposure therapy (VRET) protocol using 360º-video and eye tracking. Participants (N = 21) were randomized to either standard VRET or VRET + attention guidance training (AGT). Multi-level Bayesian models were used to test (1) whether there was an effect of condition over time and (2) whether post-treatment changes in gaze patterns mediated the effect of condition at follow-up. There was a large overall effect of the intervention on symptoms of social anxiety, as well as an effect of the AGT augmentation on changes in visual attention to audience members. There was weak evidence against an effect of condition on fear of public speaking and weak evidence supporting a mediation effect, however these estimates were strongly influenced by model priors. Taken together, our findings suggest that attention can be modified within and during VRET and that modification of visual gaze avoidance may be casually linked to reductions in social anxiety. Replication with a larger sample size is needed.