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Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by the left ILF, joining the posterior occipitotemporal regions to the temporal pole, then relayed by the uncinate fasciculus connecting the anterior temporal pole to the frontobasal areas. Nevertheless, this hypothesis was solely based on neurofunctional imaging, allowing a cortical mapping but with no anatomofunctional information regarding the white matter. Here, we report a series of 12 patients operated on under local anaesthesia for a cerebral low-grade glioma located within the left temporal lobe. Before and during resection, we used the method of intraoperative direct electrostimulation, enabling us to perform accurate and reliable anatomofunctional correlations both at cortical and subcortical levels. In order to map the ILF, using postoperative MRI, we correlated these functional findings with the anatomical locations of the sites where language disturbances were elicited by stimulations, both at cortical and subcortical levels. Our goal was to study the potential existence of parallel and distributed language networks crossing the left dominant temporal lobe, subserved by distinct subcortical pathways--namely the inferior occipitofrontal fasciculus and the ILF. Intraoperative stimulation of the anterior and middle temporal cortex elicited anomia in four patients. At the subcortical level, semantic paraphasia were induced in seven patients during stimulation of the inferior occipitofrontal fasciculus, and phonological paraphasia was generated in seven patients by stimulating the arcuate fasciculus. Interestingly, subcortical stimulation never elicited any language disturbances when performed at the level of the ILF. In addition, following a transient postoperative language deficit, all patients recovered, despite the resection of at least one part of the ILF, as confirmed by control MRI. On the basis of these results, we suggest that the "semantic ventral stream" could be constituted by at least two parallel pathways within the left dominant temporal lobe: (i) a direct pathway, the inferior occipitofrontal fasciculus, that connects the posterior temporal areas and the orbitofrontal region, crucial for language semantic processing, since it elicits semantic paraphasia when stimulated; (ii) and also possibly an indirect pathway subserved by the ILF, not indispensable for language, since it can be compensated both during stimulation and after resection.

Background: Cerebral cavernous malformations (CCMs) are common sporadic and inherited vascular malformations of the central nervous system. Although familial CCMs are linked to loss-of-function mutations in KRIT1 (CCM1), CCM2, or PDCD10 (CCM3), the genetic cause of sporadic CCMs, representing 80% of cases, remains incompletely understood.Methods: We developed two mouse models harboring mutations identified in human meningiomas with the use of the prostaglandin D2 synthase (PGDS) promoter. We performed targeted DNA sequencing of surgically resected CCMs from patients and confirmed our findings by droplet digital polymerase-chain-reaction analysis.Results: We found that in mice expressing one of two common genetic drivers of meningioma - Pik3caH1047R or AKT1E17K - in PGDS-positive cells, a spectrum of typical CCMs develops (in 22% and 11% of the mice, respectively) instead of meningiomas, which prompted us to analyze tissue samples from sporadic CCMs from 88 patients. We detected somatic activating PIK3CA and AKT1 mutations in 39% and 1%, respectively, of lesion tissue from the patients. Only 10% of lesions harbored mutations in the CCM genes. We analyzed lesions induced by the activating mutations Pik3caH1074R and AKT1E17K in mice and identified the PGDS-expressing pericyte as the probable cell of origin.Conclusions: In tissue samples from sporadic CCMs, mutations in PIK3CA were represented to a greater extent than mutations in any other gene. The contribution of somatic mutations in the genes that cause familial CCMs was comparatively small. (Funded by the Fondation ARC pour la Recherche contre le Cancer and others.). [ABSTRACT FROM AUTHOR]

Objective: Based on their clinical and radiological patterns, idiopathic CSF rhinorrhea and idiopathic intracranial hypertension can represent different clinical expressions of the same underlying pathological process. Transverse sinus stenoses are associated with both diseases, resulting in eventual restriction of the venous CSF outflow pathway. While venous sinus stenting has emerged as a promising treatment for idiopathic intracranial hypertension, its efficiency on idiopathic CSF leaks has not been very well addressed in the literature so far. The purpose of this study was to report the results of transverse sinus stenting in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses., Methods: From a prospectively collected database, the authors retrospectively collected the clinical and radiological features of the patients with spontaneous CSF leakage who were treated with venous sinus stenting., Results: Five female patients were included in this study. Transverse sinus stenoses were present in all patients, and other radiological signs of idiopathic intracranial hypertension were present in 4 patients. The median transstenotic pressure gradient was 6.5 mm Hg (range 3-9 mm Hg). Venous stenting resulted in the disappearance of the leak in 4 patients with no recurrence and no subsequent meningitis during the follow-up (median 12 months, range 6-63 months)., Conclusions: According to the authors' results, venous sinus stenting may result in the disappearance of the leak in many cases of idiopathic CSF rhinorrhea. Larger comparative studies are needed to assess the efficiency and safety of venous stenting as a first-line approach in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses.