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post inhibitory rebound

Shalmali Bivalkar-Mehla, Rajeev Mehla, Ashok Chauhan
Persistent human immunodeficiency virus 1 (HIV-1) infection provokes immune activation and depletes CD4(+ )lymphocytes, leading to acquired immunodeficiency syndrome. Uninterrupted administration of combination antiretroviral therapy (cART) in HIV-infected patients suppresses viral replication to below the detectable level and partially restores the immune system. However, cART-unresponsive residual HIV-1 infection and elusive transcriptionally silent but reactivatable viral reservoirs maintain a permanent viral DNA blue print...
November 14, 2016: Journal of Drug Targeting
Idan Elbaz, David Zada, Adi Tovin, Tslil Braun, Tali Lerer-Goldshtein, Gordon Wang, Philippe Mourrain, Lior Appelbaum
Sleep is tightly regulated by the circadian clock and homeostatic mechanisms. Although the sleep/wake cycle is known to be associated with structural and physiological synaptic changes that benefit the brain, the function of sleep is still debated. The hypothalamic hypocretin/orexin (Hcrt) neurons regulate various functions including feeding, reward, sleep, and wake. Continuous imaging of single neuronal circuits in live animals is vital to understanding the role of sleep in regulating synaptic dynamics, and the transparency of the zebrafish model enables time-lapse imaging of single synapses during both day and night...
October 12, 2016: Molecular Neurobiology
Fadi Assaf, Yitzhak Schiller
Parvalbumin (PV)-expressing interneurons exert powerful inhibitory effects on the normal cortical network; thus optogenetic activation of PV interneurons may also possess antiepileptic properties. To investigate this possibility we expressed channelrhodopsin 2 in PV interneurons by locally injecting the Cre-dependent viral vector AAV2/1-EF1a-DIO-ChETA-EYFP into the S1 barrel cortex of PV-Cre mice. Approximately 3-4 wk later recurrent electrographic seizures were evoked by local application of the chemoconvulsant 4-aminopyridine (4-AP); the ECoG and unit activity were monitored with extracellular silicone electrodes; and PV interneurons were activated optogenetically during the ictal and interictal phases...
October 1, 2016: Journal of Neurophysiology
Qingsheng Li, Jamie L Harden, Charles D Anderson, Nejat K Egilmez
Previous studies demonstrated that IL-12-driven antitumor activity is short-circuited by a rapid switch in dendritic cell (DC) function from immunogenic to tolerogenic activity. This process was dependent on IFN-γ and the tolerogenic phenotype was conferred by IDO. Extended monitoring of IDO(+) DC in the tumor-draining lymph nodes of IL-12 plus GM-CSF-treated tumor-bearing mice revealed that whereas IFN-γ induction was transient, IDO expression in DC was maintained long-term. An in vitro system modeling the IFN-γ-mediated change in DC function was developed to dissect the molecular basis of persistent IDO expression in post-IL-12 DC...
August 1, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
A Gironell, J Marin-Lahoz
INTRODUCTION: Essential tremor is the most frequent movement disorder in adults. It has been considered a benign disease, but can result in significant physical and psychosocial disability. Pharmacological treatment is still not very satisfactory. Its causation, pathophysiology and anatomy remain only partially understood. AIMS: An understanding of its neurochemical basis is essential to be able to develop more efficient therapies. We review what is currently known in this field in order to motivate further research and ideas that allow an enhanced understanding of the disease and which foster the development of new pharmacological therapies...
June 1, 2016: Revista de Neurologia
Kate Fenner, Samuel Yoon, Peter White, Melissa Starling, Paul McGreevy
Restrictive nosebands are common in equestrian sport. This is concerning, as recent evidence suggests that very tight nosebands can cause a physiological stress response, and may compromise welfare. The objective of the current study was to investigate relationships that noseband tightness has with oral behavior and with physiological changes that indicate a stress response, such as increases in eye temperature (measured with infrared thermography) and heart rate and decreases in heart rate variability (HRV)...
2016: PloS One
Michele Ferrante, Christopher F Shay, Yusuke Tsuno, G William Chapman, Michael E Hasselmo
Medial entorhinal cortex Layer-II stellate cells (mEC-LII-SCs) primarily interact via inhibitory interneurons. This suggests the presence of alternative mechanisms other than excitatory synaptic inputs for triggering action potentials (APs) in stellate cells during spatial navigation. Our intracellular recordings show that the hyperpolarization-activated cation current (Ih) allows post-inhibitory-rebound spikes (PIRS) in mEC-LII-SCs. In vivo, strong inhibitory-post-synaptic potentials immediately preceded most APs shortening their delay and enhancing excitability...
March 10, 2016: Cerebral Cortex
Lin Zhu, Allen I Selverston, Joseph Ayers
The hyperpolarization-activated inward cationic current (Ih) is known to regulate the rhythmicity, excitability, and synaptic transmission in heart cells and many types of neurons across a variety of species, including some pyloric and gastric mill neurons in the stomatogastric ganglion (STG) in Cancer borealis and Panulirus interruptus However, little is known about the role of Ih in regulating the gastric mill dynamics and its contribution to the dynamical bifurcation of the gastric mill and pyloric networks...
June 1, 2016: Journal of Neurophysiology
Andrei A Vakhtin, Piyadasa W Kodituwakku, Christopher M Garcia, Claudia D Tesche
Dependent on maternal (e.g. genetic, age) and exposure (frequency, quantity, and timing) variables, the effects of prenatal alcohol exposure on the developing fetus are known to vary widely, producing a broad range of morphological anomalies and neurocognitive deficits in offspring, referred to as fetal alcohol spectrum disorders (FASD). Maternal drinking during pregnancy remains a leading risk factor for the development of intellectual disabilities in the US. While few functional findings exist today that shed light on the mechanisms responsible for the observed impairments in individuals with FASD, animal models consistently report deleterious effects of early alcohol exposure on GABA-ergic inhibitory pathways...
2015: NeuroImage: Clinical
Faseeha Noordeen, Catherine A Scougall, Arend Grosse, Qiao Qiao, Behzad B Ajilian, Georget Reaiche-Miller, John Finnie, Melanie Werner, Ruth Broering, Joerg F Schlaak, Andrew Vaillant, Allison R Jilbert
Previous studies have demonstrated that nucleic acid polymers (NAPs) have both entry and post-entry inhibitory activity against duck hepatitis B virus (DHBV) infection. The inhibitory activity exhibited by NAPs prevented DHBV infection of primary duck hepatocytes in vitro and protected ducks from DHBV infection in vivo and did not result from direct activation of the immune response. In the current study treatment of primary human hepatocytes with NAP REP 2055 did not induce expression of the TNF, IL6, IL10, IFNA4 or IFNB1 genes, confirming the lack of direct immunostimulation by REP 2055...
2015: PloS One
J D Albright, T H Witte, B W Rohrbach, A Reed, K A Houpt
REASONS FOR PERFORMING STUDY: Crib-biting is a common oral stereotypy. Although most treatments involve prevention, the efficacy of various anti-crib devices, including surgically implanted gingival rings, has thus far not been empirically tested. OBJECTIVES: Demonstrate the effect that 2 anti-crib collars, muzzle and gingival rings have on crib-biting, other maintenance behaviours, and cortisol levels in established crib-biting horses. STUDY DESIGN: Randomised, crossover clinical trial...
November 2016: Equine Veterinary Journal
Devesh Mishra, Nicholas R Harrison, Carolina B Gonzales, Björn Schilström, Åsa Konradsson-Geuken
Ethanol abuse during adolescence may significantly alter development of the prefrontal cortex which continues to undergo structural remodeling into adulthood. Glutamatergic neurotransmission plays an important role during these brain maturation processes and is modulated by ethanol. In this study, we investigated glutamate dynamics in the medial prefrontal cortex of freely moving rats, using enzyme-based microelectrode amperometry. We analyzed the effects of an intraperitoneal ethanol injection (1 g/kg) on cortical glutamate levels in adolescent and adult rats...
2015: PloS One
Aida Calderón-Rivera, Alejandro Sandoval, Ricardo González-Ramírez, Christian González-Billault, Ricardo Felix
Low voltage-activated (LVA) T-type Ca2+ channels activate in response to subthreshold membrane depolarizations and therefore represent an important source of Ca2+ influx near the resting membrane potential. In neurons, these proteins significantly contribute to control relevant physiological processes including neuronal excitability, pacemaking and post-inhibitory rebound burst firing. Three subtypes of T-type channels (Cav3.1 to Cav3.3) have been identified, and using functional expression of recombinant channels diverse studies have validated the notion that T-type Ca2+ channels can be modulated by various endogenous ligands as well as by second messenger pathways...
2015: PloS One
Salah A Baker, Grant W Hennig, Sean M Ward, Kenton M Sanders
KEY POINTS: Platelet derived growth factor receptor α (PDGFRα(+) ) cells in colonic muscles are innervated by enteric inhibitory motor neurons. PDGFRα(+) cells generate Ca(2+) transients in response to exogenous purines and these responses were blocked by MRS-2500. Stimulation of enteric neurons, with cholinergic and nitrergic components blocked, evoked Ca(2+) transients in PDGFRα(+) and smooth muscle cells (SMCs). Responses to nerve stimulation were abolished by MRS-2500 and not observed in muscles with genetic deactivation of P2Y1 receptors...
April 15, 2015: Journal of Physiology
Fatema F Ghasia, Aasef G Shaikh
Fixational eye movements such as microsaccades are important to prevent fading. These miniature eye movements are also necessary to redirect gaze to the target after a drift. Generation of saccades and microsaccades utilizes common neural substrates. We, therefore, hypothesized that physiological modulators of saccades should also affect microsaccades. Test of this hypothesis will also provide support for the models of a microsaccade generation. We performed two experiments. In the first experiment, complete darkness led to a decrease in the frequency and velocity, but increased the amplitude of microsaccades...
April 2015: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Victor G Kramer, Said Hassounah, Susan P Colby-Germinario, Maureen Oliveira, Eric Lefebvre, Thibault Mesplède, Mark A Wainberg
OBJECTIVES: Cenicriviroc is a potent antagonist of the chemokine coreceptors 5 and 2 (CCR5/CCR2) and blocks HIV-1 entry. The CCR5 inhibitor maraviroc has been shown in tissue culture to be able to repel cell-free virions from the cell surface into extracellular space. We hypothesized that cenicriviroc might exhibit a similar effect, and tested this using clinical samples from the Phase IIb study 652-2-202, by measuring rates of intracellular DNA decline. We also monitored viral RNA levels in culture fluids...
March 2015: Journal of Antimicrobial Chemotherapy
Takahiro Ishikawa, Saeka Tomatsu, Yoshiaki Tsunoda, Jongho Lee, Donna S Hoffman, Shinji Kakei
The cerebellum generates its vast amount of output to the cerebral cortex through the dentate nucleus (DN) that is essential for precise limb movements in primates. Nuclear cells in DN generate burst activity prior to limb movement, and inactivation of DN results in cerebellar ataxia. The question is how DN cells become active under intensive inhibitory drive from Purkinje cells (PCs). There are two excitatory inputs to DN, mossy fiber and climbing fiber collaterals, but neither of them appears to have sufficient strength for generation of burst activity in DN...
2014: PloS One
E Visani, L Canafoglia, I Gilioli, D Rossi Sebastiano, V E Contarino, D Duran, F Panzica, R Cubeddu, D Contini, L Zucchelli, L Spinelli, M Caffini, E Molteni, A M Bianchi, S Cerutti, S Franceschetti, A Torricelli
Multimodal human brain mapping has been proposed as an integrated approach capable of improving the recognition of the cortical correlates of specific neurological functions. We used simultaneous EEG-fMRI (functional magnetic resonance imaging) and EEG-TD-fNIRS (time domain functional near-infrared spectroscopy) recordings to compare different hemodynamic methods with changes in EEG in ten patients with progressive myoclonic epilepsy and 12 healthy controls. We evaluated O2Hb, HHb and Blood oxygen level-dependent (BOLD) changes and event-related desynchronization/synchronization (ERD/ERS) in the α and β bands of all of the subjects while they performed a simple motor task...
November 2015: Brain Topography
Merrill J Birdno, Wei Tang, Jonathan O Dostrovsky, William D Hutchison, Warren M Grill
Thalamic deep brain stimulation (DBS) is an effective treatment for tremor, but the mechanisms of action remain unclear. Previous studies of human thalamic neurons to noted transient rebound bursting activity followed by prolonged inhibition after cessation of high frequency extracellular stimulation, and the present study sought to identify the mechanisms underlying this response. Recordings from 13 thalamic neurons exhibiting low threshold spike (LTS) bursting to brief periods of extracellular stimulation were made during surgeries to implant DBS leads in 6 subjects with Parkinson's disease...
2014: PloS One
Fabiano Baroni, Anthony N Burkitt, David B Grayden
High-frequency oscillations (above 30 Hz) have been observed in sensory and higher-order brain areas, and are believed to constitute a general hallmark of functional neuronal activation. Fast inhibition in interneuronal networks has been suggested as a general mechanism for the generation of high-frequency oscillations. Certain classes of interneurons exhibit subthreshold oscillations, but the effect of this intrinsic neuronal property on the population rhythm is not completely understood. We study the influence of intrinsic damped subthreshold oscillations in the emergence of collective high-frequency oscillations, and elucidate the dynamical mechanisms that underlie this phenomenon...
May 2014: PLoS Computational Biology
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