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https://www.readbyqxmd.com/read/28748303/a-mean-field-model-for-movement-induced-changes-in-the-beta-rhythm
#1
Áine Byrne, Matthew J Brookes, Stephen Coombes
In electrophysiological recordings of the brain, the transition from high amplitude to low amplitude signals are most likely caused by a change in the synchrony of underlying neuronal population firing patterns. Classic examples of such modulations are the strong stimulus-related oscillatory phenomena known as the movement related beta decrease (MRBD) and post-movement beta rebound (PMBR). A sharp decrease in neural oscillatory power is observed during movement (MRBD) followed by an increase above baseline on movement cessation (PMBR)...
July 26, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/28742498/subthalamic-nucleus-gamma-activity-increases-not-only-during-movement-but-also-during-movement-inhibition
#2
Petra Fischer, Alek Pogosyan, Damian M Herz, Binith Cheeran, Alexander L Green, James Fitzgerald, Tipu Z Aziz, Jonathan Hyam, Simon Little, Thomas Foltynie, Patricia Limousin, Ludvic Zrinzo, Peter Brown, Huiling Tan
Gamma activity in the subthalamic nucleus (STN) is widely viewed as a pro-kinetic rhythm. Here we test the hypothesis that rather than being specifically linked to movement execution, gamma activity reflects dynamic processing in this nucleus. We investigated the role of gamma during fast stopping and recorded scalp electroencephalogram and local field potentials from deep brain stimulation electrodes in 9 Parkinson's disease patients. Patients interrupted finger tapping (paced by a metronome) in response to a stop-signal sound, which was timed such that successful stopping would occur only in ~50% of all trials...
July 25, 2017: ELife
https://www.readbyqxmd.com/read/28739032/comparison-and-validation-of-recommended-qt-interval-correction-formulas-for-predicting-cardiac-arrhythmias-in-patients-with-advanced-heart-failure-and-cardiac-resynchronization-devices
#3
Diego Iglesias-Álvarez, Moisés Rodríguez-Mañero, Francisco Javier García-Seara, Omar Kreidieh, José Luis Martínez-Sande, Belén Álvarez-Álvarez, Xesús Alberte Fernández-López, Laila González-Melchor, Ricardo Lage-Fernández, Isabel Moscoso-Galán, José Ramón González-Juanatey
QT interval prolongation is an important marker for the development of cardiac arrhythmias (CAs). Optimal methods to estimate QT/QTc intervals in patients with ventricular pacing (VP) and its correlation with CA have not been widely investigated. We aimed to validate the currently available formulas for QT determination during VP and to compare their abilities in predicting the occurrence of CA (atrial fibrillation [AF] and malignant ventricular arrhythmias [VAs] in patients with advanced heart failure and cardiac resynchronization therapy)...
June 29, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28729830/resting-state-fluctuations-of-eeg-sensorimotor-rhythm-reflect-bold-activities-in-the-pericentral-areas-a-simultaneous-eeg-fmri-study
#4
Shohei Tsuchimoto, Shuka Shibusawa, Nobuaki Mizuguchi, Kenji Kato, Hiroki Ebata, Meigen Liu, Takashi Hanakawa, Junichi Ushiba
Blockade of the scalp electroencephalographic (EEG) sensorimotor rhythm (SMR) is a well-known phenomenon following attempted or executed motor functions. Such a frequency-specific power attenuation of the SMR occurs in the alpha and beta frequency bands and is spatially registered at primary somatosensory and motor cortices. Here, we hypothesized that resting-state fluctuations of the SMR in the alpha and beta frequency bands also covary with resting-state sensorimotor cortical activity, without involving task-related neural dynamics...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28729443/theta-and-beta-band-neural-activity-reflect-independent-syllable-tracking-and-comprehension-of-time-compressed-speech
#5
Maria Pefkou, Luc H Arnal, Lorenzo Fontolan, Anne-Lise Giraud
Recent psychophysics data suggest that speech perception is not limited by the capacity of the auditory system to encode fast acoustic variations through neural gamma activity, but rather by the time given to the brain to decode them. Whether the decoding process is bounded by the capacity of theta rhythm to follow speech syllabic rhythm, or constrained by a more endogenous top-down mechanism, e.g. involving beta activity, is unknown. We addressed the dynamics of auditory decoding in speech comprehension by challenging syllable tracking and speech decoding using comprehensible and incomprehensible time-compressed auditory sentences...
July 20, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28728744/serial-heart-rates-guideline-directed-beta-blocker-use-and-outcomes-in-patients-with-chronic-heart-failure-with-reduced-ejection-fraction
#6
Nasrien E Ibrahim, James L Januzzi, Dustin J Rabideau, Parul U Gandhi, Hanna K Gaggin
A single heart rate (HR) measurement may inform future prognosis in chronic heart failure with reduced ejection fraction (HFrEF). The importance of elevated HR across serial assessment is uncertain, particularly with well-applied guideline-directed medical therapy (GDMT) with beta blockers (BBs). In this post hoc analysis of 129 patients with chronic HFrEF in sinus rhythm, who had aggressive medication titration over 10.6 months, HR and BB use were assessed at each visit (average of 6 visits per patient). All-cause mortality was assessed...
June 15, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28728690/contemporary-outcomes-in-patients-with%C3%A2-long-qt-syndrome
#7
Ram K Rohatgi, Alan Sugrue, J Martijn Bos, Bryan C Cannon, Samuel J Asirvatham, Christopher Moir, Heidi J Owen, Katy M Bos, Teresa Kruisselbrink, Michael J Ackerman
BACKGROUND: Long QT syndrome (LQTS) is a potentially lethal cardiac channelopathy with a 1% to 5% annual risk of LQTS-triggered syncope, aborted cardiac arrest, or sudden cardiac death. OBJECTIVES: This study sought to evaluate LQTS outcomes from a single center in the contemporary era. METHODS: The authors conducted a retrospective study comprising the 606 patients with LQTS (LQT1 in 47%, LQT2 in 34%, and LQT3 in 9%) who were evaluated in Mayo Clinic's Genetic Heart Rhythm Clinic from January 1999 to December 2015...
July 25, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28713431/an-unexpected-cause-of-bradycardia-in-a-patient-with-bacterial-meningitis
#8
Petros Ioannou, Magdalini Velegraki, Stella Soundoulounaki, Achilleas Gikas, Diamantis P Kofteridis
Sinus bradycardia which is a sinus rhythm with a resting heart rate of less than 60 bpm is caused by intrinsic cardiac disorders like sick sinus syndrome or inferior myocardial infarction, metabolic and environmental causes (such as hypothyroidism and electrolyte disorders), medications (such as beta-blockers and amiodarone), infection (such as myocarditis), increased intracranial pressure, and toxic exposure, while it can sometimes be a normal phenomenon, especially during sleep, in athletes, and during pregnancy...
2017: Case Reports in Medicine
https://www.readbyqxmd.com/read/28698376/frequency-specific-directed-interactions-in-the-human-brain-network-for-language
#9
Jan-Mathijs Schoffelen, Annika Hultén, Nietzsche Lam, André F Marquand, Julia Uddén, Peter Hagoort
The brain's remarkable capacity for language requires bidirectional interactions between functionally specialized brain regions. We used magnetoencephalography to investigate interregional interactions in the brain network for language while 102 participants were reading sentences. Using Granger causality analysis, we identified inferior frontal cortex and anterior temporal regions to receive widespread input and middle temporal regions to send widespread output. This fits well with the notion that these regions play a central role in language processing...
July 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28694398/renal-sympathetic-denervation-assisted-treatment-of-electrical-storm-due-to-polymorphic-ventricular-tachycardia-in-a-patient-with-cathecolaminergic-polymorphic-ventricular-tachycardia
#10
Tolga Aksu, Tümer Erdem Güler, Kazım Serhan Özcan, Serdar Bozyel, Kıvanç Yalın
Electrical storm (ES) is not a rare clinical entity. Sympathetic hyperactivity may play critical role in development and continuation of ES. Some recent reports have demonstrated that catheter-based renal sympathetic denervation (RSD) may reduce sympathetic activation and have a potential role in reducing arrhythmic burden. A 46-year-old man was admitted to clinic with frequent implantable cardioverter defibrillator shocks and ES related to catecholaminergic polymorphic ventricular tachycardia (VT). Tachycardia was unresponsive to administration of beta-blockers, verapamil, and flecainide...
July 2017: Türk Kardiyoloji Derneği Arşivi: Türk Kardiyoloji Derneğinin Yayın Organıdır
https://www.readbyqxmd.com/read/28685702/a-focus-on-pharmacological-management-of-catecholaminergic-polymorphic-ventricular-tachycardia
#11
Claudio Barbanti, Alice Maltret, Daniel Sidi
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a channelopathy characterized by adrenergic mediated ventricular arrhythmia. Untreated CPVT is a malignant syndrome with more than 50% of arrhythmic event and up to 25% of fatal or near-fatal cardiac event at 8 years follow-up. Prevention of sudden cardiac death starts with exclusion of competitive sports. Beta blockers (BB) are the cornerstone pharmacological therapy for prevention of cardiac event in CPVT patients. Dose of BB should be the highest tolerable, preferably nadolol...
July 7, 2017: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28671629/motor-imagery-eeg-classification-for-patients-with-amyotrophic-lateral-sclerosis-using-fractal-dimension-and-fisher-s-criterion-based-channel-selection
#12
Yi-Hung Liu, Shiuan Huang, Yi-De Huang
Motor imagery is based on the volitional modulation of sensorimotor rhythms (SMRs); however, the sensorimotor processes in patients with amyotrophic lateral sclerosis (ALS) are impaired, leading to degenerated motor imagery ability. Thus, motor imagery classification in ALS patients has been considered challenging in the brain-computer interface (BCI) community. In this study, we address this critical issue by introducing the Grassberger-Procaccia and Higuchi's methods to estimate the fractal dimensions (GPFD and HFD, respectively) of the electroencephalography (EEG) signals from ALS patients...
July 3, 2017: Sensors
https://www.readbyqxmd.com/read/28649228/ras-activity-tunes-the-period-and-modulates-the-entrainment-of-the-suprachiasmatic-clock
#13
REVIEW
Tsvetan Serchov, Rolf Heumann
The small GTPase Ras is a universal eukaryotic cytoplasmic membrane-anchored protein, which regulates diverse downstream signal transduction pathways that play an important role in the proper functioning of neurons. Ras activity is a central regulator of structural and functional synaptic plasticity in the adult nervous system, where it channels neuronal responses to various extracellular cues allowing the organism to adapt to complex environmental stimuli. The suprachiasmatic nucleus (SCN) is the principle pacemaker of the circadian clock, and the circadian and photic regulation of Ras activity in the SCN is an important modulator of the clockwork...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28636506/incidence-and-predictors-of-atrial-fibrillation-after-coronary-artery-bypass-surgery-detection-by-event-loop-recorder-monitoring-from-a-contemporary-multicentre-cohort
#14
Zainab Abdel-Salam, Wail Nammas
Background Atrial fibrillation (AF) is a frequent complication after cardiac surgery. We explored the incidence and predictors of post-operative AF at 30-day follow-up in an unselected multi-centre cohort of patients undergoing elective coronary artery bypass grafting (CABG) in contemporary practice. Methods and results We enrolled 740 consecutive patients scheduled for elective CABG with or without valve surgery. Cardiac rhythm was continuously monitored for 15 days after surgery by an ambulatory event loop recorder...
March 21, 2017: Acta Cardiologica
https://www.readbyqxmd.com/read/28622355/anesthetic-action-on-the-transmission-delay-between-cortex-and-thalamus-explains-the-beta-buzz-observed-under-propofol-anesthesia
#15
Meysam Hashemi, Axel Hutt, Darren Hight, Jamie Sleigh
In recent years, more and more surgeries under general anesthesia have been performed with the assistance of electroencephalogram (EEG) monitors. An increase in anesthetic concentration leads to characteristic changes in the power spectra of the EEG. Although tracking the anesthetic-induced changes in EEG rhythms can be employed to estimate the depth of anesthesia, their precise underlying mechanisms are still unknown. A prominent feature in the EEG of some patients is the emergence of a strong power peak in the β-frequency band, which moves to the α-frequency band while increasing the anesthetic concentration...
2017: PloS One
https://www.readbyqxmd.com/read/28620312/thermodynamics-in-gliomas-interactions-between-the-canonical-wnt-beta-catenin-pathway-and-ppar-gamma
#16
REVIEW
Alexandre Vallée, Yves Lecarpentier, Rémy Guillevin, Jean-Noël Vallée
Gliomas cells are the site of numerous metabolic and thermodynamics abnormalities with an increasing entropy rate which is characteristic of irreversible processes driven by changes in Gibbs energy, heat production, intracellular acidity, membrane potential gradient, and ionic conductance. We focus our review on the opposing interactions observed in glioma between the canonical WNT/beta-catenin pathway and PPAR gamma and their metabolic and thermodynamic implications. In gliomas, WNT/beta-catenin pathway is upregulated while PPAR gamma is downregulated...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28597249/differential-regulation-of-protein-phosphatase-1-pp1-isoforms-in-human-heart-failure-and-atrial-fibrillation
#17
Stefanie Meyer-Roxlau, Simon Lämmle, Annett Opitz, Stephan Künzel, Julius P Joos, Stefan Neef, Karolina Sekeres, Samuel Sossalla, Friedrich Schöndube, Konstantin Alexiou, Lars S Maier, Dobromir Dobrev, Kaomei Guan, Silvio Weber, Ali El-Armouche
Protein phosphatase 1 (PP1) is a key regulator of important cardiac signaling pathways. Dysregulation of PP1 has been heavily implicated in cardiac dysfunctions. Accordingly, pharmacological targeting of PP1 activity is considered for therapeutic intervention in human cardiomyopathies. Recent evidence from animal models implicated previously unrecognized, isoform-specific activities of PP1 in the healthy and diseased heart. Therefore, this study examined the expression of the distinct PP1 isoforms PP1α, β, and γ in human heart failure (HF) and atrial fibrillation (AF) and addressed the consequences of β-adrenoceptor blocker (beta-blocker) therapy for HF patients with reduced ejection fraction on PP1 isoform expression...
July 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28592697/top-down-beta-enhances-bottom-up-gamma
#18
Craig G Richter, William H Thompson, Conrado A Bosman, Pascal Fries
Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake male macaque primary visual area V1, higher visual area V4 and parietal control area 7a during attentional task performance...
June 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28583875/quantitative-profiling-of-19-bile-acids-in-rat-plasma-liver-bile-and-different-intestinal-section-contents-to-investigate-bile-acid-homeostasis-and-the-application-of-temporal-variation-of-endogenous-bile-acids
#19
Tingting Yang, Ting Shu, Guanlan Liu, Huifang Mei, Xiaoyu Zhu, Xin Huang, Luyong Zhang, Zhenzhou Jiang
Bile acid homeostasis is maintained by liver synthesis, bile duct secretion, microbial metabolism and intestinal reabsorption into the blood. When drug insults result in liver damage, the variances of bile acids (BAs) are related to the physiological status of the liver. Here, we established a method to simultaneously quantify 19 BAs in rat plasma, liver, bile and different intestinal section contents (duodenum, jejunum, ileum, cecum and colon) using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to reveal the pattern of bile acid homeostasis in the enterohepatic circulation of bile acids in physiological situations...
June 2, 2017: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28569421/autonomic-nervous-system-modulation-and-clinical-outcome-after-pulmonary-vein-isolation-using-the-second-generation-cryoballoon
#20
Shinsuke Miyazaki, Hiroaki Nakamura, Hiroshi Taniguchi, Hitoshi Hachiya, Takatsugu Kajiyama, Tomonori Watanabe, Miyako Igarashi, Sadamitsu Ichijo, Kenzo Hirao, Yoshito Iesaka
BACKGROUND: The intrinsic cardiac autonomic nervous system (ANS) plays a significant role in atrial fibrillation (AF) mechanisms. This study evaluated the incidence and impact of intraprocedural vagal reactions and ANS modulation by pulmonary vein isolation (PVI) using second-generation cryoballoons on outcomes. METHODS: One hundred three paroxysmal AF patients underwent PVI with one 28-mm second-generation balloon. The median follow-up was 15.0 (12.0-18.0) months...
June 1, 2017: Journal of Cardiovascular Electrophysiology
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