Functional MRI studies investigating the impact of HIV on the brain have implicated the involvement of fronto-striatal circuitry. However, to date there is no review and meta-analysis of this work. We systematically reviewed the literature and performed a meta-analysis of functional magnetic resonance imaging (fMRI) studies in HIV-infected individuals using a well validated tool recently developed for use in fMRI, 'GingerALE'. Twenty-one studies (468 HIV+, 270 HIV- controls) were qualitatively reviewed, of which six (105 HIV+, 102 controls) utilized fMRI paradigms engaging the fronto-striatal-parietal network, making a quantitative analysis possible. Our meta-analysis revealed consistent functional differences in the left inferior frontal gyrus and caudate nucleus between infected participants and controls across these studies. This fronto-striatal dysfunction was qualitatively related to cognitive impairment, disease progression and treatment effects. Although further work needs to be done to further delineate the potentially confounding influence of substance abuse and HIV-related comorbidities, as well as HIV's effect on functional haemodynamic vascular coupling, these findings indicate that further investigation of the fronto-striatal sub-networks in HIV-infected patients is warranted.

Background: There is accumulating evidence for the role of fronto-striatal and associated circuits in obsessive–compulsive disorder (OCD) but limited and conflicting data on alterations in cortical thickness.Aims: To investigate alterations in cortical thickness and subcortical volume in OCD.Method: In total, 412 patients with OCD and 368 healthy adults underwent magnetic resonance imaging scans. Between-group analysis of covariance of cortical thickness and subcortical volumes was performed and regression analyses undertaken.Results: Significantly decreased cortical thickness was found in the OCD group compared with controls in the superior and inferior frontal, precentral, posterior cingulate, middle temporal, inferior parietal and precuneus gyri. There was also a group x age interaction in the parietal cortex, with increased thinning with age in the OCD group relative to controls.Conclusions: Our findings are partially consistent with earlier work, suggesting that group differences in grey matter volume and cortical thickness could relate to the same underlying pathology of OCD. They partially support a frontostriatal model of OCD, but also suggest that limbic, temporal and parietal regions play a role in the pathophysiology of the disorder. The group x age interaction effects may be the result of altered neuroplasticity.

Background: There is evidence to suggest that obsessive–compulsive disorder (OCD) is associated with structural abnormalities in cortico–striato–thalamic circuits, yet the extent of white matter abnormalities is not well established. In this study, we used diffusion tensor imaging (DTI) to examine white matter integrity in specific regions of interest (ROIs) in patients with OCD. Methods: Patients with OCD and sex-, age- and IQ-matched healthy controls underwent DTI. The primary objective was to explore whether patients with OCD had white matter abnormalities in the anterior limb of the internal capsule (ALIC), the uncinate fasciculus, the genu of the corpus callosum and the cingulum. The secondary objective was to evaluate the relation between fractional anisotropy and mean diffusivity in these ROIs and other clinical variables (including age at onset of OCD, OCD severity and levels of depressive and anxiety symptomatology) in patients with OCD. Results: There were 15 patients and 17 controls enrolled in our study. Compared with healthy controls, patients with OCD showed increased fractional anisotropy in bilateral regions of the ALIC adjacent to the body of the caudate, as well as decreased fractional anisotropy in the right anterior limb near the head of the caudate. Patients also had decreased mean diffusivity in the body of the right cingulum and the left anterior cingulum compared with controls. Correlational analyses revealed significant associations of fractional anisotropy and mean diffusivity in select circuits with OCD, depression and anxiety severity scores. Limitations: Inclusion of patients with OCD receiving pharmacotherapy may have been a limitation. In addition, the patients were heterogeneous in terms of their obsessive–compulsive symptom profiles; we did not distinguish between different obsessive–compulsive symptom dimensions. Conclusion: The study results provide further evidence for OCD-related white matter abnormalities in the ALIC and cingulum, consistent with a corticostriatal model of OCD.

Background: Neurosurgeons regularly plan their surgery using magnetic resonance imaging (MRI) images, which may show a clear distinction between the area to be resected and the surrounding healthy brain tissue depending on the nature of the pathology. However, this distinction is often unclear with the naked eye during the surgical intervention, and it may be difficult to infer depth and an accurate volumetric interpretation from a series of MRI image slices. Objectives: In this work, MRI data are used to create affordable patient-specific 3-dimensional (3D) scale models of the brain which clearly indicate the location and extent of a tumour relative to brain surface features and important adjacent structures. Methods: This is achieved using custom software and rapid prototyping. In addition, functionally eloquent areas identified using functional MRI are integrated into the 3D models. Results: Preliminary in vivo results are presented for 2 patients. The accuracy of the technique was estimated both theoretically and by printing a geometrical phantom, with mean dimensional errors of less than 0.5 mm observed. Conclusions: This may provide a practical and cost-effective tool which can be used for training, and during neurosurgical planning and intervention.