Epileptiform activity in the mouse visual cortex interferes with cortical processing in connected areas.

Epileptiform activity is associated with impairment of brain function even in absence of seizures, as demonstrated by failures in various testing paradigm in presence of hypersynchronous interictal spikes (ISs). Clinical evidence suggests that cognitive deficits might be directly caused by the anomalous activity rather than by its underlying etiology. Indeed, we seek to understand whether ISs interfere with neuronal processing in connected areas not directly participating in the hypersynchronous activity in an acute model of epilepsy. Here we cause focal ISs in the visual cortex of anesthetized mice and we determine that, even if ISs do not invade the opposite hemisphere, the local field potential is subtly disrupted with a modulation of firing probability imposed by the contralateral IS activity. Finally, we find that visual processing is altered depending on the temporal relationship between ISs and stimulus presentation. We conclude that focal ISs interact with normal cortical dynamics far from the epileptic focus, disrupting endogenous oscillatory rhythms and affecting information processing.

Common Genetic Conditions of Ischemic Stroke to Keep in Mind.

Stroke is a complex disease resulting from the interplay of genetics and environment. In some instances (mainly in young adults) stroke is the direct result of a monogenic disease. Among the monogenic causes of stroke, the diseases which are most frequently encountered in the adult general neurological practice are CADASIL, Fabry and mitochondrial diseases. Brain MRI and clinical features may frequently lead to a correct molecular diagnosis. Here we review the single-gene causes of ischemic stroke, with special regard to the associated features which may help in the diagnostic approach.