A Novel Focal Seizure Pattern Generated in Superficial Layers of the Olfactory Cortex.

Seizure patterns identified in focal epilepsies caused by diverse etiologies are likely due to different pathogenic mechanisms. We describe here a novel, region-specific focal seizure pattern that mimics seizure activity observed in a subpopulation of patients submitted to presurgical monitoring with intracerebral electrodes. Distinctive seizure-like events (SLEs) are induced in the olfactory regions by acute treatment of both tangential brain slices and the isolated guinea pig brain with the potassium channel blocker 4-aminopyridine. Analysis of field potentials, intracellular activities, and extracellular potassium changes demonstrates that SLEs in the piriform cortex initiate in the superficial layer 1 lacking principal neurons with an activity-dependent increase of extracellular potassium. SLE progression (but not onset) does not require the participation of synaptic transmission and is mediated by diffusion of potassium to deep cortical layers. The novel seizure pattern here described is not observed in other cortical regions; it is proposed to rely on the peculiar organization of the superficial piriform cortex layers, which are characterized by unmyelinated axons and perisynaptic astroglial envelopes. This study reveals a sequence of ictogenic events in the olfactory cortex that were never described before in other cortical structures and supports the notion that altered potassium homeostasis and unmyelinated fibers may represent a potential vehicle for focal ictogenesis.SIGNIFICANCE STATEMENT We describe a novel seizure pattern peculiar of the olfactory cortex that resembles focal seizures with low-voltage fast activity at onset observed in humans. The findings suggest that network mechanisms responsible for seizure onset can be region specific.

Heterozygous D90A-SOD1 mutation in a patient with facial onset sensory motor neuronopathy (FOSMN) syndrome: a bridge to amyotrophic lateral sclerosis.

OBJECTIVE: To describe a patient with facial onset sensory motor neuronopathy (FOSMN) syndrome associated with a heterozygous D90A mutation in superoxide dismutase (SOD1) gene. METHODS: The patient underwent neurological and neurophysiologic examinations, including blink and jaw reflexes, sural nerve and skin biopsies, and analysis of TARDBP, FUS and C9ORF72 genes. RESULTS: Neurological examination showed diffuse fasciculations, bulbar signs, hypotrophy and weakness of facial, neck, shoulder girdle and first interosseus muscles, and absent corneal reflex. Neurophysiologic studies demonstrated abnormal blink and jaw reflexes and reduced sensory nerve action potentials at upper limbs. Sural nerve and skin biopsies revealed mild loss of large and small nerve fibres. Genetic analysis demonstrated a heterozygous D90A-SOD1 mutation. CONCLUSIONS: FOSMN syndrome has been recently described in patients with slowly progressive bulbar and upper limb amyotrophy. Sensory symptoms, mainly involving the trigeminal territory, typically precede the onset of motor weakness by months or years. The pathogenesis of FOSMN syndrome is unknown and possible immune-mediated mechanisms have been claimed. Our findings support the hypothesis that FOSMN syndrome is a primary degenerative disorder that widens the spectrum of motor neuron diseases.

Yet another in vitro evidence that natural compounds introduced by diet have anti-amyloidogenic activities and can counteract neurodegenerative disease depending on aging.

A major issue in Alzheimer's disease (AD) research is to find some new therapeutic drug which decrease Amyloid-beta (Aß) aggregation. From a therapeutic point of view the major question is whether pharmacological inhibition of inflammation pathways will be able to safely reverse or slow the course of disease. Natural compounds are capable of binding to different targets implicated in AD and exert neuroprotective effects. Aim of this study was to evaluate the in vitro inhibition of Aß1-42 fibrillogenesis in presence of Gallic acid, Rutin, Melatonin and ProvinolsTM . We performed the analysis with Transmission and Scanning Electron Microscopy, and with X-ray microanalysis. Samples treated with Rutin, that arises from phenylalanine via the phenylpropanoid pathway, show the best effective result obtained because a significantly fibril inhibition activity is detectable compared to the other compounds. Melatonin shows a better inhibitory activity than ProvinolsTM and Gallic acid at the considered concentrations.

APP mutations in the Aß coding region are associated with abundant cerebral deposition of Aß38.

Aß is the main component of amyloid deposits in Alzheimer disease (AD) and its aggregation into oligomers, protofibrils and fibrils is considered a seminal event in the pathogenesis of AD. Aß with C-terminus at residue 42 is the most abundant species in parenchymal deposits, whereas Aß with C-terminus at residue 40 predominates in the amyloid of the walls of large vessels. Aß peptides with other C-termini have not yet been thoroughly investigated. We analysed Aß38 in the brains of patients with Aß deposition linked to sporadic and familial AD, hereditary cerebral haemorrhage with amyloidosis, or Down syndrome. Immunohistochemistry, confocal microscopy, immunoelectron microscopy, immunoprecipitation and the electrophoresis separation of low molecular weight aggregates revealed that Aß38 accumulates consistently in the brains of patients carrying APP mutations in the Aß coding region, but was not detected in the patients with APP mutations outside the Aß domain, in the patients with presenilin mutations or in subjects with Down syndrome. In the patients with sporadic AD, Aß38 was absent in the senile plaques, but it was detected only in the vessel walls of a small subset of patients with severe cerebral amyloid angiopathy. Our results suggest that APP mutations in the Aß coding region favour Aß38 accumulation in the brain and that the molecular mechanisms of Aß deposition in these patients may be different from those active in patients with familial AD associated with other genetic defects and sporadic AD.

The diagnostic challenge of Divry van Bogaert and Sneddon Syndrome: Report of three cases and literature review.

Divry van Bogaert Syndrome (DBS) is a familial juvenile-onset disorder characterized by livedo racemosa, white matter disease, dementia, epilepsy and angiographic finding of "cerebral angiomatosis". A similar syndrome including livedo racemosa and cerebrovascular disease, often associated with anticardiolipin antibodies, has been described as Sneddon Syndrome (SS) highlighting the question whether these two conditions have to be considered different entities or indeed different features of a unique syndrome. Herein, we report the clinical, neuroradiological, histopathological findings and follow up of three cases diagnosed as Divry-van Bogaert Syndrome, including an updated review of literature of both DBS and SS cases. Our findings support the assumption that DBS and SS are different disease entities. DBS is characterized by the typical angiographic feature of angiomatosis, a hereditary trait and a juvenile onset of cognitive impairment and leukoaraiosis, whereas SS has less severe manifestations of cerebrovascular disease associated with livedo racemosa but without the characteristic cerebral angiography. The report of our cases and the literature review underline the necessity of a detailed work-up and the collection of larger series to better clarify the DBS and SS phenotype and course.

Perlecan is recruited by dystroglycan to nodes of Ranvier and binds the clustering molecule gliomedin.

Fast neural conduction requires accumulation of Na(+) channels at nodes of Ranvier. Dedicated adhesion molecules on myelinating cells and axons govern node organization. Among those, specific laminins and dystroglycan complexes contribute to Na(+) channel clustering at peripheral nodes by unknown mechanisms. We show that in addition to facing the basal lamina, dystroglycan is found near the nodal matrix around axons, binds matrix components, and participates in initial events of nodogenesis. We identify the dystroglycan-ligand perlecan as a novel nodal component and show that dystroglycan is required for the selective accumulation of perlecan at nodes. Perlecan binds the clustering molecule gliomedin and enhances clustering of node of Ranvier components. These data show that proteoglycans have specific roles in peripheral nodes and indicate that peripheral and central axons use similar strategies but different molecules to form nodes of Ranvier. Further, our data indicate that dystroglycan binds free matrix that is not organized in a basal lamina.

Presynaptic c-Jun N-terminal Kinase 2 regulates NMDA receptor-dependent glutamate release.

Activation of c-Jun N-terminal kinase (JNK) signaling pathway is a critical step for neuronal death occurring in several neurological conditions. JNKs can be activated via receptor tyrosine kinases, cytokine receptors, G-protein coupled receptors and ligand-gated ion channels, including the NMDA glutamate receptors. While JNK has been generally associated with postsynaptic NMDA receptors, its presynaptic role remains largely unexplored. Here, by means of biochemical, morphological and functional approaches, we demonstrate that JNK and its scaffold protein JIP1 are also expressed at the presynaptic level and that the NMDA-evoked glutamate release is controlled by presynaptic JNK-JIP1 interaction. Moreover, using knockout mice for single JNK isoforms, we proved that JNK2 is the essential isoform in mediating this presynaptic event. Overall the present findings unveil a novel JNK2 localization and function, which is likely to play a role in different physiological and pathological conditions.