Abnormalities within and beyond the cortico-striato-thalamo-cortical circuitry in medication-free patients with OCD revealed by the fractional amplitude of low-frequency fluctuations and resting-state functional connectivity.

Neuroimaging studies of obsessive-compulsive disorder (OCD) often focus on the cortico-striato-thalamo-cortical (CSTC) circuitry, but recent studies have found abnormal spontaneous brain activity in regions outside the CSTC circuitry in patients with OCD using resting-state functional magnetic resonance imaging. Researchers have not clearly determined whether changes in spontaneous brain activity within and beyond the CSTC circuitry coexist in medication-free patients with OCD. To address this question, we recruited 64 medication-free patients with OCD and 60 matched healthy controls (HCs) to investigate their spontaneous brain activity by measuring the fractional amplitude of low-frequency fluctuation (fALFF) and resting-state functional connectivity. Patients with OCD showed increased fALFF values in the left dorsolateral prefrontal cortex (DLPFC) and decreased fALFF values in the right rolandic operculum compared with HCs. Furthermore, patients with OCD exhibited significantly increased functional connectivity between the left DLPFC and the left cerebellum and reduced negative functional connectivity between the right rolandic operculum and the left precuneus. These findings provided new insights into the pathophysiological model of OCD, which may include CSTC circuitry and regions outside this circuitry.

Using Interactive 3D Visualisations in Neuropsychiatric Education.

Obsessive compulsive disorder (OCD) is a neuropsychiatric disorder with a global prevalence of 2-3%. OCD can have an enormous impact on the lives of those with the disorder, with some studies suggesting suicidal ideation is present in over 50% of individuals with OCD, and other data showing a significant number of individuals attempt suicide. It is therefore important that individuals with OCD receive the best possible treatment. A greater understanding of the underlying pathophysiology of neuropsychiatric disorders among professionals and future clinicians can lead to improved treatment. However, data suggests that many students and clinicians experience "neurophobia", a lack of knowledge or confidence in cases involving the nervous system. In addition, research suggests that the relationship many students have with neurological conditions deteriorates over time, and can persist into practice.If individuals living with conditions such as OCD are to receive the best possible treatment, it is crucial that those administering care are equipped with a thorough understanding of such disorders. While research has shown that the use of interactive 3D models can improve anatomy education and more specifically neurology education, the efficacy of using of such models to engage with neuropsychiatric conditions, specifically OCD, has not been assessed. This study seeks to address this gap.In this study an interactive application for Android devices was designed using standardised software engineering methods in order to improve neuropsychiatry literacy by empowering self-pace learning through interactive 3D visualisations and animations of the neural circuitry involved in OCD. A pilot test and a usability assessment were conducted among five postgraduate life science students. Findings relating to user experience were promising, and pre-test vs. post-test evaluation suggested encouraging outcomes regarding the effectiveness of the application in improving the knowledge and understanding of OCD. In short, this study suggests that interactive 3D visualisations can improve neuropsychiatry education. For this reason, more efforts should be made to construct similar applications in order to ensure patients always receive the best possible care. Fig. 2.1 A diagrammatic representation of the CSTC circuit, based on a similar diagram by Robertson et al. (2017).

Deep brain stimulation in the treatment of obsessive-compulsive disorder: current perspectives.

Deep brain stimulation (DBS) is a neuro-psychosurgical technique widely accepted in movement disorders, such as Parkinson's disease. Since 1999, DBS has been explored for severe, chronic and treatment-refractory psychiatric diseases. Our review focuses on DBS in obsessive-compulsive disorder (OCD), considered as a last treatment resort by most of learned societies in psychiatry. Two main stimulation areas have been studied: the striatal region and the subthalamic nucleus. But, most of the trials are open-labeled, and the rare controlled ones have failed to highlight the most efficient target. The recent perspectives are otherwise encouraging. Indeed, clinicians are currently considering other promising targets. A case series of 2 patients reported a decrease in OCD symptoms after DBS in the medial forebrain bundle and an open-label study is exploring bilateral habenula stimulation. New response criteria are also investigating such as quality of life, or subjective and lived-experience. Moreover, first papers about cost-effectiveness which is an important criterion in decision making, have been published. The effectiveness of tractography-assisted DBS or micro-assisted DBS is studying with the aim to improve targeting precision. In addition, a trial involving rechargeable pacemakers is undergoing because this mechanism could be efficient and have a positive impact on cost-effectiveness. A recent trial has discussed the possibility of using combined cognitive behavioral therapy (CBT) and DBS as an augmentation strategy. Finally, based on RDoc Research, the latest hypotheses about the understanding of cortico-striato-thalamo-cortical circuits could offer new directions including clinical predictors and biomarkers to perform adaptive closed-loop systems in the next future.

Brain circuitries of obsessive compulsive disorder: a systematic review and meta-analysis of diffusion tensor imaging studies.

The potential role of white matter (WM) abnormalities in the pathophysiology of obsessive compulsive disorder (OCD) is substantially unexplored. Apart from alterations in the WM tracts within cortico-striato-thalamo-cortical circuitry, recent theorizations predict the existence of more widespread WM abnormalities. In this paper we systematically reviewed the current diffusion tensor imaging literature in OCD and purposely evaluated the prevalence and functional significance of specific WM tissue changes in the disorder. The relationship between clinical variables (medication status, symptom severity) and WM microstructural changes was also assessed. The reviewed studies are consistent with the existence of microstructural alterations in the fronto-basal pathways targeting the orbitofrontal cortex and the anterior cingulate cortex. Moreover, altered anatomical connectivity between lateral frontal and parietal regions and microstructural abnormalities in intra-hemispheric bundles linking distinctive areas of the prefrontal cortex to posterior parietal and occipital association cortices, are consistently reported. Finally, microstructural abnormalities in the corpus callosum, characterized by decreased connectivity in the rostrum and hyperconnectivity in the genu, are substantiated by a large body of evidence.