Abnormalities of White Matter Microstructure in Unmedicated Obsessive-Compulsive Disorder and Changes after Medication

BACKGROUND: Abnormalities of myelin integrity have been reported in obsessive-compulsive disorder (OCD) using multi-parameter maps of diffusion tensor imaging (DTI). However, it was still unknown to what degree these abnormalities might be affected by pharmacological treatment. OBJECTIVE: To investigate whether the abnormalities of white matter microstructure including myelin integrity exist in OCD and whether they are affected by medication. METHODOLOGY AND PRINCIPAL FINDINGS: Parameter maps of DTI, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were acquired from 27 unmedicated OCD patients (including 13 drug-naïve individuals) and 23 healthy controls. Voxel-based analysis was then performed to detect regions with significant group difference. We compared the DTI-derived parameters of 15 patients before and after 12-week Selective Serotonin Reuptake Inhibitor (SSRI) therapies. Significant differences of DTI-derived parameters were observed between OCD and healthy groups in multiple structures, mainly within the fronto-striato-thalamo-cortical loop. An increased RD in combination with no change in AD among OCD patients was found in the left medial superior frontal gyrus, temporo-parietal lobe, occipital lobe, striatum, insula and right midbrain. There was no statistical difference in DTI-derived parameters between drug-naive and previously medicated OCD patients. After being medicated, OCD patients showed a reduction in RD of the left striatum and right midbrain, and in MD of the right midbrain. CONCLUSION: Our preliminary findings suggest that abnormalities of white matter microstructure, particularly in terms of myelin integrity, are primarily located within the fronto-striato-thalamo-cortical circuit of individuals with OCD. Some abnormalities may be partly reversed by SSRI treatment

Visual attention and action: How cueing, direct mapping, and social interactions drive orienting

Despite considerable interest in both action perception and social attention over the last 2 decades, there has been surprisingly little investigation concerning how the manual actions of other humans orient visual attention. The present review draws together studies that have measured the orienting of attention, following observation of another’s goal-directed action. Our review proposes that, in line with the literature on eye gaze, action is a particularly strong orienting cue for the visual system. However, we additionally suggest that action may orient visual attention using mechanisms, which gaze direction does not (i.e., neural direct mapping and corepresentation). Finally, we review the implications of these gaze-independent mechanisms for the study of attention to action. We suggest that our understanding of attention to action may benefit from being studied in the context of joint action paradigms, where the role of higher level action goals and social factors can be investigated

Pathology of peste des petits ruminants virus infection in small ruminants and concurrent infections

Peste des petits ruminant (PPR) is a systemic viral disease of goats and sheep characterized by gastrointestinal and respiratory system lesions with high rate of mortality. Rhinitis, conjunctivitis, serous-mucopurulent naso-ocular discharge, pneumonia, coughing, dispnea, erosive-ulcerative oral lesions, and diarrhea are the most prominent clinicopathological features of the disease. Histopathologically, pseudomembraneous stomatitis, necrotic tonsillitis, fibrinohemorrhagic enteritis, and proliferative interstitial pneoumonia are seen. Syncytial cells and cytoplasmic and/or nuclear eosinophilic inclusion bodies are considered as pathognomonic. Like the other morbilli viruses, PPR virus can also cause lesions in the kidney, brain, and abomasum. The PPRV tropism can be explained by the mechanism in which PPRV binds to receptors on the cell surface. The PPR in small ruminants often shows coassociation with secondary viral, bacterial, and parasitary infections