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neuronal synchronization

Marijn Bart Martens, Monica Frega, Jessica Classen, Lisa Epping, Elske Bijvank, Marco Benevento, Hans van Bokhoven, Paul Tiesinga, Dirk Schubert, Nael Nadif Kasri
Heterozygous mutations or deletions in the human Euchromatin histone methyltransferase 1 (EHMT1) gene cause Kleefstra syndrome, a neurodevelopmental disorder that is characterized by autistic-like features and severe intellectual disability (ID). Neurodevelopmental disorders including ID and autism may be related to deficits in activity-dependent wiring of brain circuits during development. Although Kleefstra syndrome has been associated with dendritic and synaptic defects in mice and Drosophila, little is known about the role of EHMT1 in the development of cortical neuronal networks...
October 21, 2016: Scientific Reports
Thomas Burwick, Alexandros Bouras
The communication-through-coherence (CTC) hypothesis states that a sending group of neurons will have a particularly strong effect on a receiving group if both groups oscillate in a phase-locked ("coherent") manner (Fries, 2005, 2015). Here, we consider a situation with two visual stimuli, one in the focus of attention and the other distracting, resulting in two sites of excitation at an early cortical area that project to a common site in a next area. Taking a modeler's perspective, we confirm the workings of a mechanism that was proposed by Bosman et al...
October 20, 2016: Neural Computation
Chien-Cheng Chen, Christopher J Bockisch, Dominik Straumann, Melody Ying-Yu Huang
Spontaneous eye movements of zebrafish larvae in the dark consist of centrifugal saccades that move the eyes from a central to an eccentric position and postsaccadic centripetal drifts. In a previous study, we showed that the fitted single-exponential time constants of the postsaccadic drifts are longer in the temporal-to-nasal (T->N) direction than in the nasal-to-temporal (N->T) direction. In the present study, we further report that saccadic peak velocities are higher and saccadic amplitudes are larger in the N->T direction than in the T->N direction...
2016: Frontiers in Systems Neuroscience
Ariel Haimovici, Pablo Balenzuela, Enzo Tagliazucchi
Synchronization of brain activity fluctuations is believed to represent communication between spatially distant neural processes. These inter-areal functional interactions develop in the background of a complex network of axonal connections linking cortical and sub-cortical neurons, termed the human "structural connectome". Theoretical considerations and experimental evidence support the view that the human brain can be modeled as a system operating at a critical point between ordered (sub-critical) and disordered (super-critical) phases...
October 19, 2016: Brain Connectivity
Anthony G Hudetz, Jeannette A Vizuete, Siveshigan Pillay, George A Mashour
Consciousness has been linked to the repertoire of brain states at various spatiotemporal scales. Anesthesia is thought to modify consciousness by altering information integration in cortical and thalamocortical circuits. At a mesoscopic scale, neuronal populations in the cortex form synchronized ensembles whose characteristics are presumably state-dependent but this has not been rigorously tested. In this study, spontaneous neuronal activity was recorded with 64-contact microelectrode arrays in primary visual cortex of chronically instrumented, unrestrained rats under stepwise decreasing levels of desflurane anesthesia (8%, 6%, 4%, and 2% inhaled concentrations) and wakefulness (0% concentration)...
October 14, 2016: Neuroscience
Mahua Chatterjee, Fernando Perez de Los Cobos Pallares, Alex Loebel, Michael Lukas, Veronica Egger
During odor sensing the activity of principal neurons of the mammalian olfactory bulb, the mitral and tufted cells (MTCs), occurs in repetitive bursts that are synchronized to respiration, reminiscent of hippocampal theta-gamma coupling. Axonless granule cells (GCs) mediate self- and lateral inhibitory interactions between the excitatory MTCs via reciprocal dendrodendritic synapses. We have explored long-term plasticity at this synapse by using a theta burst stimulation (TBS) protocol and variations thereof...
2016: Neural Plasticity
Elham Kordijaz, Ali Moghimi, Masoud Fereidoni, Saeedeh Asadi, Ali Shamsizadeh, Ali Roohbakhsh
Convulsive seizures are due to abnormal synchronous and repetitive neuronal discharges in the central nervous system (CNS). Finding new therapeutics to overcome the side effects of the current drug therapies and to increase their effectiveness is ongoing. Orexin-A and orexin-B are brain neuropeptides originating from postero-lateral hypothalamic neurons. Studies show that orexins, through activation of OX1 and OX2 receptors, have excitatory effects in the CNS. Accordingly, the present study was designed to evaluate the effect of OX1 receptor antagonist (SB-334867) on seizure- and anxiety-related behaviors of pentylenetetrazol (PTZ) kindled rats...
October 14, 2016: Fundamental & Clinical Pharmacology
Chiara Sarappa, Elena Salvatore, Alessandro Filla, Sirio Cocozza, Cinzia Valeria Russo, Francesco Saccà, Arturo Brunetti, Giuseppe De Michele, Mario Quarantelli
The fractional Amplitude of Low Frequency Fluctuations (fALFF) and the degree of local synchronization (Regional Homogeneity - ReHo) of resting-state BOLD signal have been suggested to map spontaneous neuronal activity and local functional connectivity, respectively. We compared voxelwise, independent of atrophy, the fALFF and ReHo patterns of 11 presymptomatic (ps-HD) and 28 symptomatic (sHD) Huntington's disease mutation carriers, with those of 40 normal volunteers, and tested their possible correlations with the motor and cognitive subscores of the Unified Huntington's Disease Rating Scale...
October 12, 2016: Brain Imaging and Behavior
Carien S Lansink, Guido T Meijer, Jan V Lankelma, Martin A Vinck, Jadin C Jackson, Cyriel M A Pennartz
: The use of information from the hippocampal memory system in motivated behavior depends on its communication with the ventral striatum. When an animal encounters cues that signal subsequent reward, its reward expectancy is raised. It is unknown, however, how this process affects hippocampal dynamics and their influence on target structures, such as ventral striatum. We show that, in rats, reward-predictive cues result in enhanced hippocampal theta and beta band rhythmic activity during subsequent action, compared with uncued goal-directed navigation...
October 12, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
T Weber, K Namikawa, B Winter, K Müller-Brown, R Kühn, W Wurst, R W Köster
The zebrafish is a well-established model organism to study in vivo mechanisms of cell communication, differentiation and function. Existing cell ablation methods are either invasive thereby creating additional tissue damage and potential infection sites, or they rely on the cellular expression of prokaryotic enzymes and the use of antibiotic drugs as cell-death-inducing compounds. We have recently established a novel inducible genetic cell ablation system that is based on Tamoxifen-inducible Caspase8-activity, thereby exploiting mechanisms of cell death intrinsic to most cell types...
October 11, 2016: Development
Carolina Roza, Irene Mazo, Iván Rivera-Arconada, Elsa Cisneros, Ismel Alayón, José A López-García
The superficial dorsal horn contains large numbers of interneurons which process afferent and descending information to generate the spinal nociceptive message. Here, we set out to evaluate whether adjustments in patterns and/or temporal correlation of spontaneous discharges of these neurons are involved in the generation of central sensitization caused by peripheral nerve damage. Multielectrode arrays were used to record from discrete groups of such neurons in slices from control or nerve damaged mice. Whole-cell recordings of individual neurons were also obtained...
October 10, 2016: Pflügers Archiv: European Journal of Physiology
Sven Gottschalk, Thomas Felix Fehm, Xose Luís Deán-Ben, Vassiliy Tsytsarev, Daniel Razansky
Visualization of whole brain activity during epileptic seizures is essential for both fundamental research into the disease mechanisms and the development of efficient treatment strategies. It has been previously discussed that pathological synchronization originating from cortical areas may reinforce backpropagating signaling from the thalamic neurons, leading to massive seizures through enhancement of high frequency neural activity in the thalamocortical loop. However, the study of deep brain neural activity is challenging with the existing functional neuroimaging methods due to lack of adequate spatiotemporal resolution or otherwise insufficient penetration into subcortical areas...
January 2017: Neurophotonics
Shennan A Weiss, Iren Orosz, Noriko Salamon, Stephanie Moy, Linqing Wei, Maryse A Van't Klooster, Robert T Knight, Ronald M Harper, Anatol Bragin, Itzhak Fried, Jerome Engel, Richard J Staba
OBJECTIVE: Ripples (80-150 Hz) recorded from clinical macroelectrodes have been shown to be an accurate biomarker of epileptogenic brain tissue. We investigated coupling between epileptiform spike phase and ripple amplitude to better understand the mechanisms that generate this type of pathologic ripple (pRipple) event. METHODS: We quantified phase amplitude coupling (PAC) between epileptiform electroencephalography (EEG) spike phase and ripple amplitude recorded from intracranial depth macroelectrodes during episodes of sleep in 12 patients with mesial temporal lobe epilepsy...
October 10, 2016: Epilepsia
Olusoji A T Afuwape, Catherine R Wasser, Thomas Schikorski, Ege T Kavalali
Earlier studies suggest that spontaneous and evoked neurotransmitter release processes are maintained by synaptic vesicles which are segregated into functionally distinct pools. However, direct interrogation of the link between this putative synaptic vesicle pool heterogeneity and neurotransmission has been difficult. To examine this link, we tagged vesicles with horseradish peroxidase (HRP) - a heme containing plant enzyme - or antibodies against synaptotagmin-1 (syt1). Filling recycling vesicles in hippocampal neurons with HRP and subsequent treatment with hydrogen peroxide (H2 O2 ) modified the properties of neurotransmitter release depending on the route of HRP uptake...
October 10, 2016: Journal of Physiology
Abdujelil Abdurahman, Haijun Jiang
This paper investigates the exponential synchronization of delayed memristor-based neural networks (MNNs) with discontinuous activation functions. Based on the framework of Filippov solution and differential inclusion theory, using new analytical techniques and introducing suitable Lyapunov functionals, some novel sufficient conditions ensuring the exponential synchronization of considered networks are established via two types of discontinuous controls: linear feedback control and adaptive control. In particular, we extend the discontinuous control strategies for neural networks with continuous dynamics to MNNs with discontinuous activations...
September 10, 2016: Neural Networks: the Official Journal of the International Neural Network Society
Wolf Singer, Andreea Lazar
The discovery of stimulus induced synchronization in the visual cortex suggested the possibility that the relations among low-level stimulus features are encoded by the temporal relationship between neuronal discharges. In this framework, temporal coherence is considered a signature of perceptual grouping. This insight triggered a large number of experimental studies which sought to investigate the relationship between temporal coordination and cognitive functions. While some core predictions derived from the initial hypothesis were confirmed, these studies, also revealed a rich dynamical landscape beyond simple coherence whose role in signal processing is still poorly understood...
2016: Frontiers in Computational Neuroscience
Rosario Gajardo-Gómez, Valeria C Labra, Juan A Orellana
Under physiological conditions, microglia adopt a resting phenotype associated with the production of anti-inflammatory and neurotrophic factors. In response to a wide variety of insults, these cells shift to an activated phenotype that is necessary for the proper restoration of brain homeostasis. However, when the intensity of a threat is relatively high, microglial activation worsens the progression of damage rather than providing protection, with potentially significant consequences for neuronal survival...
2016: Frontiers in Molecular Neuroscience
Valentina Zamboni, Maria Armentano, Gabriella Sarò, Elisa Ciraolo, Alessandra Ghigo, Giulia Germena, Alessandro Umbach, Pamela Valnegri, Maria Passafaro, Valentina Carabelli, Daniela Gavello, Veronica Bianchi, Patrizia D'Adamo, Ivan de Curtis, Nadia El-Assawi, Alessandro Mauro, Lorenzo Priano, Nicola Ferri, Emilio Hirsch, Giorgio R Merlo
During brain development, the small GTPases Rac1/Rac3 play key roles in neuronal migration, neuritogenesis, synaptic formation and plasticity, via control of actin cytoskeleton dynamic. Their activity is positively and negatively regulated by GEFs and GAPs molecules, respectively. However their in vivo roles are poorly known. The ArhGAP15 gene, coding for a Rac-specific GAP protein, is expressed in both excitatory and inhibitory neurons of the adult hippocampus, and its loss results in the hyperactivation of Rac1/Rac3...
October 7, 2016: Scientific Reports
Ana R Inácio, Azat Nasretdinov, Julia Lebedeva, Roustem Khazipov
Early stages of sensorimotor system development in mammals are characterized by the occurrence of spontaneous movements. Whether and how these movements support correlated activity in developing sensorimotor spinal cord circuits remains unknown. Here we show highly correlated activity in sensory and motor zones in the spinal cord of neonatal rats in vivo. Both during twitches and complex movements, movement-generating bursts in motor zones are followed by bursts in sensory zones. Deafferentation does not affect activity in motor zones and movements, but profoundly suppresses activity bursts in sensory laminae and results in sensorimotor uncoupling, implying a primary role of sensory feedback in sensorimotor synchronization...
October 7, 2016: Nature Communications
Rodrigo Echeveste, Claudius Gros
The study of balanced networks of excitatory and inhibitory neurons has led to several open questions. On the one hand it is yet unclear whether the asynchronous state observed in the brain is autonomously generated, or if it results from the interplay between external drivings and internal dynamics. It is also not known, which kind of network variabilities will lead to irregular spiking and which to synchronous firing states. Here we show how isolated networks of purely excitatory neurons generically show asynchronous firing whenever a minimal level of structural variability is present together with a refractory period...
2016: Frontiers in Computational Neuroscience
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