Zika virus infection histories in brain development.

An outbreak of births of microcephalic patients in Brazil motivated multiple studies on this incident. The data left no doubt that infection by Zika virus (ZIKV) was the cause, and that this virus promotes reduction in neuron numbers and neuronal death. Analysis of patients' characteristics revealed additional aspects of the pathology alongside the decrease in neuronal number.

Hippocampus-retrosplenial cortex interaction is increased during phasic REM and contributes to memory consolidation.

Hippocampal (HPC) theta oscillation during post-training rapid eye movement (REM) sleep supports spatial learning. Theta also modulates neuronal and oscillatory activity in the retrosplenial cortex (RSC) during REM sleep. To investigate the relevance of theta-driven interaction between these two regions to memory consolidation, we computed the Granger causality within theta range on electrophysiological data recorded in freely behaving rats during REM sleep, both before and after contextual fear conditioning.

Two decades of research towards a potential first anti-epileptic drug.

The basic mechanisms by which brain insults, such as trauma, stroke or status epilepticus produce epilepsy are not completely understood, and effective preventive measures and treatment are still not available in the clinical setting. Over the last 2 decades we have conducted several studies with animal models of epilepsy (rodents and non-human primates) and demonstrated that drugs that modify neuronal plastic processes, such as anticholinergic agents (e.g.

Is REM sleep a paradoxical state?: Different neurons are activated in the cingulate cortices and the claustrum during wakefulness and paradoxical sleep hypersomnia.

Michel Jouvet proposed in 1959 that REM sleep is a paradoxical state since it was characterized by the association of a cortical activation similar to wakefulness (W) with muscle atonia. Recently, we showed using cFos as a marker of activity that cortical activation during paradoxical sleep (PS) was limited to a few limbic cortical structures in contrast to W during which all cortices were strongly activated. However, we were not able to demonstrate whether the same neurons are activated during PS and W and to rule out that the activation observed was not linked with stress induced by the flowerpot method of PS deprivation.

Association between brain morphology and electrophysiological features in Congenital Zika Virus Syndrome: A cross-sectional, observational study.

Background: Intrauterine infection with the Zika virus (ZIKV) has been connected to severe brain malformations, microcephaly, and abnormal electrophysiological activity.

Methods: We describe the interictal electroencephalographic (EEG) recordings of 47 children born with ZIKV-derived microcephaly. EEGs were recorded in the first year of life and correlated with brain morphology.

Levetiracetam Reduced the Basal Excitability of the Dentate Gyrus without Restoring Impaired Synaptic Plasticity in Rats with Temporal Lobe Epilepsy.

Temporal lobe epilepsy (TLE), the most common type of focal epilepsy, affects learning and memory; these effects are thought to emerge from changes in synaptic plasticity. Levetiracetam (LEV) is a widely used antiepileptic drug that is also associated with the reversal of cognitive dysfunction. The long-lasting effect of LEV treatment and its participation in synaptic plasticity have not been explored in early chronic epilepsy.

Disentangling chemical and electrical effects of status epilepticus-induced dentate gyrus abnormalities.

In rodents, status epilepticus (SE) triggered by chemoconvulsants can differently affect the proliferation and fate of adult-born dentate granule cells (DGCs). It is unknown whether abnormal neurogenesis results from intracellular signaling associated with drug-receptor interaction, paroxysmal activity, or both. To test the contribution of these factors, we systematically compared the effects of kainic acid (KA)- and pilocarpine (PL)-induced SE on the morphology and localization of DGCs generated before or after SE in the ipsi- and contralateral hippocampi of mice.

The GCN2 inhibitor IMPACT contributes to diet-induced obesity and body temperature control.

IMPACT, a highly conserved protein, is an inhibitor of the eIF2α kinase GCN2. In mammals, it is preferentially expressed in neurons. Knock-down of IMPACT expression in neuronal cells increases basal GCN2 activation and eIF2α phosphorylation and decreases translation initiation.

Identification of Hypsarrhythmia in Children with Microcephaly Infected by Zika Virus.

Hypsarrhythmia is an electroencephalographic pattern specific to some epileptic syndromes that affect children under one year of age. The identification of this pattern, in some cases, causes disagreements between experts, which is worrisome since an inaccurate diagnosis can bring complications to the infant. Despite the difficulties in visually identifying hypsarrhythmia, options of computerized assistance are scarce.

Memory corticalization triggered by REM sleep: mechanisms of cellular and systems consolidation.

Once viewed as a passive physiological state, sleep is a heterogeneous and complex sequence of brain states with essential effects on synaptic plasticity and neuronal functioning. Rapid-eye-movement (REM) sleep has been shown to promote calcium-dependent plasticity in principal neurons of the cerebral cortex, both during memory consolidation in adults and during post-natal development. This article reviews the plasticity mechanisms triggered by REM sleep, with a focus on the emerging role of kinases and immediate-early genes for the progressive corticalization of hippocampus-dependent memories.

Electrophysiological Evidence That the Retrosplenial Cortex Displays a Strong and Specific Activation Phased with Hippocampal Theta during Paradoxical (REM) Sleep.

It is widely accepted that cortical neurons are similarly more activated during waking and paradoxical sleep (PS; aka REM) than during slow-wave sleep (SWS). However, we recently reported using Fos labeling that only a few limbic cortical structures including the retrosplenial cortex (RSC) and anterior cingulate cortex (ACA) contain a large number of neurons activated during PS hypersomnia. Our aim in the present study was to record local field potentials and unit activity from these two structures across all vigilance states in freely moving male rats to determine whether the RSC and the ACA are electrophysiologically specifically active during basal PS episodes.

Music Proficiency and Quantification of Absolute Pitch: A Large-Scale Study among Brazilian Musicians.

Absolute pitch (AP) is the ability to identify and name the pitch of a sound without external reference. Often, accuracy and speed at naming isolated musical pitches are correlated with demographic, biological, and acoustical parameters to gain insight into the genesis and evolution of this ability in specific cohorts. However, the majority of those studies were conducted in North America, Europe, or Asia.

Seizures triggered by pentylenetetrazol in marmosets made chronically epileptic with pilocarpine show greater refractoriness to treatment.

The efficiency of most of the new antiepileptic drugs (AEDs) on clinical trials still falls short the success reported in pre-clinical studies, possibly because the validity of the animal models is insufficient to fully represent the human pathology. To improve the translational value for testing AEDs, we propose the use of non-human primates. Here, we suggest that triggering limbic seizures with low doses of PTZ in pilocarpine-treated marmosets might provide a more effective basis for the development of AED.

Human Brain Expansion during Evolution Is Independent of Fire Control and Cooking.

What makes humans unique? This question has fascinated scientists and philosophers for centuries and it is still a matter of intense debate. Nowadays, human brain expansion during evolution has been acknowledged to explain our empowered cognitive capabilities. The drivers for such accelerated expansion remain, however, largely unknown.

Ethological Evaluation of the Effects of Social Defeat Stress in Mice: Beyond the Social Interaction Ratio.

In rodents, repeated exposure to unavoidable aggression followed by sustained sensory treat can lead to prolonged social aversion. The chronic social defeat stress model explores that phenomenon and it has been used as an animal model for human depression. However, some authors have questioned whether confounding effects may arise as the model also boosts anxiety-related behaviors.

AMPA receptors mediate passive avoidance deficits induced by sleep deprivation.

The present study addressed the effects of sleep deprivation (SD) on AMPA receptor (AMPAR) binding in brain regions associated with learning and memory, and investigated whether treatment with drugs acting on AMPAR could prevent passive avoidance deficits in sleep deprived animals. [(3)H]AMPA binding and GluR1 in situ hybridization signals were quantified in different brain regions of male Wistar rats either immediately after 96 h of sleep deprivation or after 24h of sleep recovery following 96 h of sleep deprivation. Another group of animals were sleep deprived and then treated with either the AMPAR potentiator, aniracetam (25, 50 and 100mg/kg, acute administration) or the AMPAR antagonist GYKI-52466 (5 and 10mg/kg, acute and chronic administration) before passive avoidance training.

Reduced hippocampal dentate cell proliferation and impaired spatial memory performance in aged-epileptic rats.

Increased adult neurogenesis is observed after training in hippocampal-dependent tasks and also after acutely induced status epilepticus (SE) although the specific roles of these cells are still a matter of debate. In this study, we investigated hippocampal cell proliferation and differentiation and the spatial learning performance in young or aged chronically epileptic rats. Status was induced by pilocarpine in 3 or 20-month old rats.

m1 Acetylcholine Receptor Expression is Decreased in Hippocampal CA1 region of Aged Epileptic Animals.

In the present study, we investigated the possible additive effects of epilepsy and aging on the expression of m1 muscarinic acetylcholine receptors (AChR) in the rat hippocampus. Young (3 months) and Aged (20 months) male, Wistar rats were treated with pilocarpine to induce status epilepticus (SE). Immunohistochemical procedure for m1 AChR detection was performed 2 months after pilocarpine-induced SE.

Microinjection of GABAergic agents into the anterior nucleus of the thalamus modulates pilocarpine-induced seizures and status epilepticus.

The anterior nucleus of the thalamus (AN) has been suggested as a potential target for seizure modulation in animal models and patients with refractory epilepsy. We investigate whether microinjections of GABAergic agonists into the AN were protective against pilocarpine-induced generalized seizures and status epilepticus (SE). Rats were treated with bilateral AN injections of muscimol (160 or 80 nmol), bicuculline (15 nmol), or saline (controls) 20 min prior to pilocarpine administration (350 mg/kg i.

Dynamics of evoked local field potentials in the hippocampus of epileptic rats with spontaneous seizures.

A change in neuronal network excitability within the hippocampus is one of the hallmarks of temporal lobe epilepsy (TLE). In the dentate gyrus (DG), however, neuronal loss and mossy fiber sprouting are associated with enhanced inhibition rather than progressive hyperexcitability. The aim of this study was to investigate how alterations in excitability take place in association with spontaneous seizures expressed in the DG before, during, and after a seizure.

Vesicular acetylcholine transporter knock-down mice are more susceptible to pilocarpine induced status epilepticus.

The pilocarpine (PILO) animal model of Temporal Lobe Epilepsy (TLE) portrays the most common changes in hippocampal circuitry found in human TLE. The acute cholinergic insult induces status epilepticus (SE), which triggers an overwhelming set of plastic events that result on late spontaneous recurrent limbic seizures. It has been suggested that the cholinergic system plays an important role in the synchronization required for ictogenesis.

Synaptic plasticity of the CA3 commissural projection in epileptic rats: an in vivo electrophysiological study.

The hippocampal commissural system has recently been found to participate in the generation of mirror foci after kainate-induced epileptiform discharges. In the present study we have evaluated the electrophysiological alterations in the ventral commissural hippocampal system that originates in the pyramidal CA3 cells and connects to the contralateral CA3 pyramidal cells. The recordings were performed in epileptic rats 24 h after an early behavioural spontaneous seizure between 5 and 21 days after pilocarpine-induced status epilepticus.

Effects of herbimycin A in the pilocarpine model of temporal lobe epilepsy.

Pilocarpine-induced status epilepticus (SE) causes widespread tyrosine phosphorylation in the brain. It has been postulated that this intracellular signal may mediate potentially epileptogenic changes in the morphology and physiology of particular brain regions, including the hippocampus. The present study evaluated the effects of herbimycin A, a protein tyrosine kinase (PTK) inhibitor, over the acute (during which intense biochemical and electrophysiological activation occurs) and the chronic phase (characterized by spontaneous and recurrent epileptic seizures and the presence of synaptic reorganization, e.