International audienceReasoning by analogy allows us to link distinct domains of knowledge and to transfer solutions from one domain to another. Analogical reasoning has been studied using various tasks that have generally required the consideration of the relationships between objects and their integration to infer an analogy schema. However, these tasks varied in terms of the level and the nature of the relationships to consider (e.g., semantic, visuospatial). The aim of this study was to identify the cerebral network involved in analogical reasoning and its specialization based on the domains of information and task specificity. We conducted a coordinate-based meta-analysis of 27 experiments that used analogical reasoning tasks. The left rostrolateral prefrontal cortex was one of the regions most consistently activated across the studies. A comparison between semantic and visuospatial analogy tasks showed both domain-oriented regions in the inferior and middle frontal gyri and a domain-general region, the left rostrolateral prefrontal cortex, which was specialized for analogy tasks. A comparison of visuospatial analogy to matrix problem tasks revealed that these two relational reasoning tasks engage, at least in part, distinct right and left cerebral networks, particularly separate areas within the left rostrolateral prefrontal cortex. These findings highlight several cognitive and cerebral differences between relational reasoning tasks that can allow us to make predictions about the respective roles of distinct brain regions or networks. These results also provide new, testable anatomical hypotheses about reasoning disorders that are induced by brain damage. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc

Background New diagnostic tools have been developed to improve the diagnosis of infectious encephalitis. Using a prospective cohort of encephalitis patients, our objective was to identify possible clusters of patients with similar patterns among encephalitis of unknown cause, and to describe to what extent the patient’s initial presentation may be predictive of encephalitis etiology, particularly Herpes simplex virus (HSV) and Varicella-zona virus (VZV). Methods The national cohort of infectious encephalitis in France (ENCEIF) is an ongoing prospective cohort study implemented in France in 2016. Patients presenting with a documented or suspected acute infectious encephalitis were included. Focusing on the variables describing the initial presentation, we performed a factor analysis of mixed data (FAMD) to investigate a pattern of association between the initial presentation of the patient and the etiologic pathogen. Results As of 1st August 2018, data from 349 patients were analysed. The most frequent pathogens were HSV (25%), VZV (11%), Tick-borne encephalitis virus (6%), Listeria (5%), Influenza virus (3%), and encephalitis of unknown cause (EUC) (34%). Using the FAMD, it was not possible to identify a specific pattern related to the group of EUC. Age, temporal or haemorrhagic lesions, and cerebral spinal fluid lymphocytosis were significantly associated with HSV/VZV encephalitis. Conclusion No initial clinical/imaging/biology pattern was identified at admission among EUC, despite the improvement of diagnostic tools. In this context, the recommendation for a universal, early probabilistic initial treatment against HSV and VZV is still relevant, regardless of the initial clinical presentation of the encephalitis.

Multinodular and vacuolating neuronal tumor of the cerebrum is a rare supratentorial brain tumor described for the first time in 2013. Here, we report 11 cases of infratentorial lesions showing similar striking imaging features consisting of a cluster of low T1-weighted imaging and high T2-FLAIR signal intensity nodules, which we referred to as multinodular and vacuolating posterior fossa lesions of unknown significance. No relationship was found between the location of the lesion and clinical symptoms. A T2-FLAIR hypointense central dot sign was present in images of 9/11 (82%) patients. Cortical involvement was present in 2/11 (18%) of patients. Only 1 nodule of 1 multinodular and vacuolating posterior fossa lesion of unknown significance showed enhancement on postcontrast T1WI. DWI, SWI, MRS, and PWI showed no malignant pattern. Lesions did not change in size or signal during a median follow-up of 3 years, suggesting that multinodular and vacuolating posterior fossa lesions of unknown significance are benign malformative lesions that do not require surgical intervention or removal. ABBREVIATIONS: IQR interquartile range; MVNT ¼ multinodular and vacuolating neuronal tumor of the cerebrum; MV-PLUS ¼ multinodular and vacuolating posterior fossa lesions of unknown significance M ultinodular and vacuolating neuronal tumor of the cerebrum (MVNT) is a rare brain tumor described for the first time in 2013 and added in the World Health Organization Classification of Tumors of the Central Nervous System in 2016. 1,2 Its prevalence and pathophysiology are unknown. It is often asymptomatic and discovered incidentally. It remains unclear whether MVNT should be considered a true neoplasm or a malformative lesion. 1-7 MVNTs have been reported to show highly suggestive imaging features, especially with MR imaging. 8-16 MVNT consists of the coalescence of small T2-weighted imaging and T2-FLAIR