Periodic Bursts Research Articles

Bursting oscillations with boundary homoclinic bifurcations in a Filippov-type Chua’s circuit

A modified version of the typical Chua’s circuit, which possesses a periodic external excitation and a piecewise nonlinear resistor, is considered to investigate the possible bursting oscillations and the dynamical mechanism in the Filippov system. Two new symmetric periodic bursting oscillations are observed when the frequency of external excitation is far less than the natural one. Besides the conventional Hopf bifurcation, two non-smooth bifurcations, i.e., boundary homoclinic bifurcation and non-smooth fold limit cycle bifurcation, are discussed when the whole excitation term is regarded as a bifurcation parameter. The sliding solution of the Filippov system and pseudo-equilibrium bifurcation of the sliding vector field on the switching manifold are analysed theoretically. Based on the analysis of the bifurcations and the sliding solution, the dynamical mechanism of the bursting oscillations is revealed. The external excitation plays an important role in generating bursting oscillations. That is, bursting oscillations may be formed only if the excitation term passes through the boundary homoclinic bifurcation. Otherwise, they do not occur. In addition, the time intervals between two symmetric adjacent spikes of the bursting oscillations and the duration of the system staying at the stable pseudonode are dependent on the excitation frequency.

Multiepoch VLBI of L Dwarf Binary 2MASS J0746+2000AB: Precise Mass Measurements and Confirmation of Radio Emission from Both Components

Abstract Surveys have shown that up to 1/10th of all ultracool dwarfs (UCDs) are appreciable radio emitters, with their emission attributed to a combination of gyrosynchrotron radiation and the electron cyclotron maser instability. 2M J0746+2000AB is a close stellar binary comprised of an L0 and L1.5 dwarf that was previously identified as a source of 5 GHz radio emission. We used Very Long Baseline Interferometry (VLBI) to precisely track the radio emission over seven epochs in 2010–2017, and found both components to be radio emitters—the first such system identified—with the secondary component as the dominant source of emission in all epochs. The previously identified 2.07 hr periodic bursts were confirmed to originate from the secondary component, although an isolated burst was also identified from the primary component. We additionally fitted the VLBI absolute astrometric positions jointly with existing relative orbital astrometry derived from optical/infrared observations with Markov Chain Monte Carlo methods to determine the orbital parameters of the two components. We found the masses of the primary and secondary optical components to be 0.0795 ± 0.0003 M ⊙, and 0.0756 ± 0.0003 M ⊙, respectively, representing the most precise mass estimates of any UCDs to date. Finally, we place a 3σ upper limit of 0.9 M jup au on the mass and separation of planets orbiting either of the two components.

Bursts Characterize Coagulation of Rods in a Quiescent Fluid.

Under favorable conditions, microscopic phytoplankton cells dwelling in the oceans can divide rapidly and reach high concentrations, forming blooms that span kilometers and last for weeks. When blooms collapse, dead cells settle and aggregate into "marine snow" particles, resulting in a large and climatically important vertical flux of carbon from the ocean surface to its depth, a process known as the "biological pump." To date, the formation of marine snow has been modeled as coagulation between spherical particles driven by gravitational settling and turbulent mixing, characterized by coagulation dynamics that converge onto time-independent concentrations of aggregates. However, many phytoplankton species are elongated and how their rodlike shape affects the aggregation process has remained unknown. Here, we study marine snow formation in a quiescent fluid assuming the constituent particles are elongated and form bundles upon encounter. We derive the collision kernel between dissimilar rods settling under gravity and discover that the most frequent collisions occur between the thinnest and thickest bundles, rather than between bundles of similar size. As a consequence, in the full coagulation model that combines exponential growth with settling, the thin-thick coupling can lead to statistically stationary states where the concentrations of aggregates of different size oscillate in time, exhibiting periodic bursts. The bursts are predicted to occur on the scale of a week and eventually lead to broadening of aggregate size spectra and may thus be highly relevant for plankton dynamics and the carbon cycle in the ocean.

Synchrony Drives Motor Cortex Beta Bursting, Waveform Dynamics, and Phase-Amplitude Coupling in Parkinson's Disease.

Several lines of inquiry have separately identified beta oscillations, synchrony, waveform shape, and phase-amplitude coupling as important but sometimes inconsistent factors in the pathophysiology of Parkinson's disease. What has so far been lacking is a means by which these neurophysiological parameters are interrelated and how they relate to clinical symptomatology. To clarify the relationship among oscillatory power, bursting, synchrony, and phase-amplitude coupling, we recorded local field potentials/electrocorticography from hand motor and premotor cortical area in human subjects with c (N = 10) and Parkinson's disease (N = 22) during deep brain stimulator implantation surgery (14 females, 18 males). We show that motor cortical high beta oscillations in Parkinson's disease demonstrate increased burst durations relative to essential tremor patients. Notably, increased corticocortical synchrony between primary motor and premotor cortices precedes motor high beta bursts, suggesting a possible causal relationship between corticocortical synchrony and localized increases in beta power. We further show that high beta bursts are associated with significant changes in waveform shape and that beta-encoded phase-amplitude coupling is more evident during periods of high beta bursting. These findings reveal a deeper structure to the pathologic changes identified in the neurophysiology of Parkinson's disease, suggesting mechanisms by which the treatment may be enhanced using targeted network synchrony disruption approaches.SIGNIFICANCE STATEMENT Understanding Parkinson's disease pathophysiology is crucial for optimizing symptom management. Present inconsistencies in the literature may be explained by temporal transients in neural signals driven by transient fluctuations in network synchrony. Synchrony may also act as a unifying phenomenon for the pathophysiological observations reported in Parkinson's disease. Here, simultaneous recordings from motor cortices show that increases in network beta synchrony anticipate episodes of beta bursting. We furthermore identify beta bursting as being associated with changes in waveform shape and increases in phase-amplitude coupling. Our results identify network synchrony as a driver of various pathophysiological observations reported in the literature and account for inconsistencies in the literature by virtue of the temporally variable nature of the phenomenon.

Burst mechanisms and burst synchronization in a system of coupled type-I and type-II neurons

The rich dynamics of a system comprising of a Type-I neuron coupled to a Type-II neuron via an electrical synapse (gap junction) are explored in this paper. Diverse dynamical behaviour ranging from quiescence and periodic spiking, to bursting and burst synchronization, were observed for different coupling schemes. The bifurcation mechanisms underlying the various bursts observed were identified. We report a unique burst mechanism, based on a focus/node bifurcation, occurring for bidirectionally coupled neurons. We attempt to understand the physical basis for the transitions from one burst pattern to another and also between the different aforementioned forms of dynamical behaviour observed on varying the coupling strength, in both unidirectionally and bidirectionally coupled neurons. The various dynamical regimes of the coupled system are exhaustively studied and demarcated through parameter plots. Type-I and type-II neurons exhibit mutually phase synchronized burst patterns at large values of the coupling which tend towards complete synchronization on increasing the coupling strength. Such collective dynamical behaviour can have important implications in biological systems.

A burst-based unsupervised method for detecting review spammer groups

With the development of e-commerce, online shopping has become a part of people's life. As customers often refer to online product reviews for shopping, sellers often collude with review spammers in writing fake reviews to promote or demote target products. In particular, spammers working in groups are more harmful than individual attacks. To detect such spammer groups, previous researchers proposed some frequent item mining based algorithms and graph-based algorithms. In this paper, we propose a method called GSDB (Group Spam Detection algorithm based on review Burst). Our algorithm first locates target products attacked by spammers by detecting the abnormality of product rating distribution. As group spammers usually post many fake reviews within a short period, we design a burst-based algorithm that discovers candidate spammer groups in reviewbursts using the Kernel Density Estimation algorithm. As some innocent reviewers may coincidently review during the burst period, we formulate a variety of individual spam indicators to measure the spamicity of the reviewers to isolate the candidate spammer groups. Finally, we design a series of group spam indicators to measure and classify the spamicity of spammer groups. Experimental results show that our proposed GSDB algorithm outperforms state-of-the-art algorithms.

Firing multistability in a locally active memristive neuron model

The theoretical, numerical and experimental demonstrations of firing dynamics in isolated neuron are of great significance for the understanding of neural function in human brain. In this paper, a new type of locally active and non-volatile memristor with three stable pinched hysteresis loops is presented. Then, a novel locally active memristive neuron model is established by using the locally active memristor as a connecting autapse, and both firing patterns and multistability in this neuronal system are investigated. We have confirmed that, on the one hand, the constructed neuron can generate multiple firing patterns like periodic bursting, periodic spiking, chaotic bursting, chaotic spiking, stochastic bursting, transient chaotic bursting and transient stochastic bursting. On the other hand, the phenomenon of firing multistability with coexisting four kinds of firing patterns can be observed via changing its initial states. It is worth noting that the proposed neuron exhibits such firing multistability previously unobserved in single neuron model. Finally, an electric neuron is designed and implemented, which is extremely useful for the practical scientific and engineering applications. The results captured from neuron hardware experiments match well with the theoretical and numerical simulation results.

Modeling a Nociceptive Neuro-Immune Synapse Activated by ATP and 5-HT in Meninges: Novel Clues on Transduction of Chemical Signals Into Persistent or Rhythmic Neuronal Firing.

Extracellular ATP and serotonin (5-HT) are powerful triggers of nociceptive firing in the meninges, a process supporting headache and whose cellular mechanisms are incompletely understood. The current study aimed to develop, with the neurosimulator NEURON, a novel approach to explore in silico the molecular determinants of the long-lasting, pulsatile nature of migraine attacks. The present model included ATP and 5-HT release, ATP diffusion and hydrolysis, 5-HT uptake, differential activation of ATP P2X or 5-HT3 receptors, and receptor subtype-specific desensitization. The model also tested the role of branched meningeal fibers with multiple release sites. Spike generation and propagation were simulated using variable contribution by potassium and sodium channels in a multi-compartment fiber environment. Multiple factors appeared important to ensure prolonged nociceptive firing potentially relevant to long-lasting pain. Crucial roles were observed in: (i) co-expression of ATP P2X2 and P2X3 receptor subunits; (ii) intrinsic activation/inactivation properties of sodium Nav1.8 channels; and (iii) temporal and spatial distribution of ATP/5-HT release sites along the branches of trigeminal nerve fibers. Based on these factors we could obtain either persistent activation of nociceptive firing or its periodic bursting mimicking the pulsating nature of pain. In summary, our model proposes a novel tool for the exploration of peripheral nociception to test the contribution of clinically relevant factors to headache including migraine pain.

First Evidence of Local E×B Drift in the Divertor Influencing the Structure and Stability of Confined Plasma near the Edge of Fusion Devices.

The structure of the edge plasma in a magnetic confinement system has a strong impact on the overall plasma performance. We uncover for the first time a magnetic-field-direction dependent density shelf, i.e., local flattening of the density radial profile near the magnetic separatrix, in high confinement plasmas with low edge collisionality in the DIII-D tokamak. The density shelf is correlated with a doubly peaked density profile near the divertor target plate, which tends to occur for operation with the ion B×∇B drift direction away from the X-point, as currently employed for DIII-D advanced tokamak scenarios. This double-peaked divertor plasma profile is connected via the E×B drifts, arising from a strong radial electric field induced by the radial electron temperature gradient near the divertor target. The drifts lead to the reversal of the poloidal flow above the divertor target, resulting in the formation of the density shelf. The edge density shelf can be further enhanced at higher heating power, preventing large, periodic bursts of the plasma, i.e., edge-localized modes, in the edge region, consistent with ideal magnetohydrodynamics calculations.

NbO2 Memristive Neurons for Burst‐Based Perceptron

Neuromorphic computing using spike‐based learning has broad prospects in reducing computing power. Memristive neurons composed with two locally active memristors have been used to mimic the dynamical behaviors of biological neurons. Herein, the dynamic operating conditions of NbO2‐based memristive neurons and their transformation boundaries between the spiking and the bursting are comprehensively investigated. Furthermore, the underlying mechanism of bursting is analyzed, and the controllability of the number of spikes during each burst period is demonstrated. Finally, pattern classification and information transmitting in a perceptron neural network by using the number of spikes per bursting period to encode information is proposed. The results show a promising approach for the practical implementation of neuristor in spiking neural networks.

Ictal quantitative surface electromyography correlates with postictal EEG suppression

ObjectiveTo test the hypothesis that neurophysiologic biomarkers of muscle activation during convulsive seizures reveal seizure severity and to determine whether automatically computed surface EMG parameters during seizures can predict postictal generalized EEG suppression (PGES), indicating increased risk for sudden unexpected death in epilepsy. Wearable EMG devices have been clinically validated for automated detection of generalized tonic-clonic seizures. Our goal was to use quantitative EMG measurements for seizure characterization and risk assessment.MethodsQuantitative parameters were computed from surface EMGs recorded during convulsive seizures from deltoid and brachial biceps muscles in patients admitted to long-term video-EEG monitoring. Parameters evaluated were the durations of the seizure phases (tonic, clonic), durations of the clonic bursts and silent periods, and the dynamics of their evolution (slope). We compared them with the duration of the PGES.ResultsWe found significant correlations between quantitative surface EMG parameters and the duration of PGES (p < 0.001). Stepwise multiple regression analysis identified as independent predictors in deltoid muscle the duration of the clonic phase and in biceps muscle the duration of the tonic-clonic phases, the average silent period, and the slopes of the silent period and clonic bursts. The surface EMG-based algorithm identified seizures at increased risk (PGES ≥20 seconds) with an accuracy of 85%.ConclusionsIctal quantitative surface EMG parameters correlate with PGES and may identify seizures at high risk.Classification of evidenceThis study provides Class II evidence that during convulsive seizures, surface EMG parameters are associated with prolonged postictal generalized EEG suppression.

Periodic Fast Radio Bursts as a Probe of Extragalactic Asteroid Belts

Abstract The periodic activity of the repeating fast radio burst (FRB) 180916.J0158+65 was recently reported by the CHIME/FRB Collaboration team. From this source 28 bursts not only show a ∼16 day period with an active phase of ∼4.0 days, but they also exhibit a broken power law in differential energy distribution. In this Letter, we suggest that FRB 180916.J0158+65-like periodic FRBs could provide a unique probe of extragalactic asteroid belts (EABs), based on our previously proposed pulsar-EAB impact model, in which repeating FRBs arise from an old-aged, slowly spinning, moderately magnetized pulsar traveling through an EAB around another stellar-mass object. These two objects form a binary, and thus the observed period is in fact the orbital period. We show that this model can be used to well interpret all of the observed data of FRB 180916.J0158+65. Furthermore, we constrain the EAB’s physical properties and find that (1) the outer radius of the EAB is at least an order of magnitude smaller than that of its analog in the solar system, (2) the differential size distribution of the EAB’s asteroids at small diameters (large diameters) is shallower (steeper) than that of solar system small objects, and (3) the two belts have a comparable mass.

Genomic characterization of a novel virulent phage infecting Shigella fiexneri and isolated from sewage

Shigella fiexneri phage SGF2 is a novel lytic phage isolated from a sewage sample. Morphological characterization indicates that phage SGF2 is a member of the Podoviridae family, producing virions with an isometric head (82.6 ± 8 nm diameter) and a short non-contractile tail (length 52 ± 8 nm). This phage specifically infected the Shigella fiexneri. One-step growth curves indicated that the burst period of phage SGF2 is 30 min, with an approximate burst size of 38. The full-length genome was sequenced and potential virulence genes were detected. We will discuss the potential application of phage SGF2 in phage therapy.

Magnetar birth: rotation rates and gravitational-wave emission

ABSTRACT Understanding the evolution of the angle χ between a magnetar’s rotation and magnetic axes sheds light on the star’s birth properties. This evolution is coupled with that of the stellar rotation Ω, and depends on the competing effects of internal viscous dissipation and external torques. We study this coupled evolution for a model magnetar with a strong internal toroidal field, extending previous work by modelling – for the first time in this context – the strong protomagnetar wind acting shortly after birth. We also account for the effect of buoyancy forces on viscous dissipation at late times. Typically, we find that χ → 90° shortly after birth, then decreases towards 0° over hundreds of years. From observational indications that magnetars typically have small χ, we infer that these stars are subject to a stronger average exterior torque than radio pulsars, and that they were born spinning faster than ∼100–300 Hz. Our results allow us to make quantitative predictions for the gravitational and electromagnetic signals from a newborn rotating magnetar. We also comment briefly on the possible connection with periodic fast radio burst sources.

Left cardiac sympathetic denervation reduces skin sympathetic nerve activity in patients with long QT syndrome

Although left cardiac sympathetic denervation (LCSD) is an effective antiarrhythmic therapy for patients with long QT syndrome (LQTS), direct evidence of reduced sympathetic activity after LCSD in humans is limited. The purpose of this study was to assess skin sympathetic nerve activity (SKNA) in patients with LQTS undergoing LCSD. We prospectively enrolled 17 patients with LQTS who underwent LCSD between 2017 and 2019. SKNA recordings from the left arm (L-SKNA) and chest (C-SKNA) leads were performed before and after LCSD. Mean SKNA, burst activity, and nonburst activity of L-SKNA and C-SKNA were analyzed. The mean patient age was 21 ± 9 years (8 men 47%). The longest baseline corrected QT value was 497 ± 55 ms at rest and 531 ± 38 ms on exercise stress testing. Five patients (29.4%) had previous LQTS-triggered cardiac events including syncope, documented torsades de pointes, and ventricular fibrillation. In the 24 hours after LCSD, mean L-SKNA decreased from 1.25 ± 0.64 to 0.85 ± 0.33 μV (P = .005) and mean C-SKNA from 1.36 ± 0.67 to 1.05 ± 0.49 μV (P = .11). The frequency of episodes of SKNA bursts recorded from the left-arm lead (2.87 ± 1.61 bursts per minute vs 1.13 ± 0.99 bursts per minute; P < .001) and mean L-SKNA during burst (1.82 ± 0.79 μV vs 1.15 ± 0.44 μV; P < .001) and nonburst (1.09 ± 0.60 μV vs 0.75 ± 0.32 μV; P = .03) periods significantly decreased after LCSD, while the frequency of episodes of SKNA bursts recorded from the chest lead (P = .57) and mean C-SKNA during burst (P = .44) and nonburst (P = .10) periods did not change significantly. No arrhythmic events were documented after 11.9 months (range 3.0-22.2 months) of follow-up. LCSD provides an inhibitory effect on cardiac sympathetic activity by suppressing burst discharge as measured by SKNA.

Co‐modulation of the Na+/K+ pump and hyperpolarization‐activated currents as a mechanism for robust neuromodulation

Specialized oscillatory circuits, central pattern generators (CPGs), control rhythmic motor behaviors such as locomotion and breathing. To accommodate a motor pattern to environmental changes and behavioral goals, neuromodulators adjust the dynamics of CPGs by orchestrating changes in various ionic currents in a wide range of their biophysical parameters to expand temporal characteristics of the functional pattern. Recent studies provide evidence that the Na+/K+ pump contributes to the dynamics of CPGs and is controlled by neuromodulation [1– 4]. In the leech heartbeat CPG, the neuropeptide myomodulin reduces the period of bursting activity by increasing the hyperpolarization‐activated (h)‐current and decreasing the Na+/K+ pump current [4]. The application of myomodulin reduces the period of oscillatory activity by 17%. Application of Cs+, which is an h‐current blocker, increases the period of bursting by 24% relative to control. The application of myomodulin along with Cs+ decreases the period by 12% relative to treatment with Cs+ [4]. Here we investigate how the period of a bursting can be controlled in a wide range while functional bursting is maintained with a focus on the role of the Na+/K+ pump. We also investigate the risk associated with multistability in neuronal dynamics.We optimized a model of the leech heart interneuron (HN), which includes the Na+/K+ pump current and intracellular Na+ dynamics [1] and investigated the activity regimes of pairs of mutually inhibitory coupled HNs forming half‐center oscillators (HCOs). HCOs form the kernel of the leech heartbeat CPG. We investigated eight model variants representing combinations of three experimental treatments: the blockade of chemical synapses representing the application of bicuculline, the blockade of h‐current representing the application of Cs+, and the enhancement of the h‐current and inhibition of the Na+/K+ pump current representing the application of myomodulin. The model captures the qualitative trends in change of cycle period observed in experiments with myomodulin and Cs+. We found ranges of parameters where neurons showed functional bursting. The coordinated changes of maximal conductance of h‐current (Gh) and maximal pump activity (IPumpMax) increases the range of period of functional bursting as well as the range of parameters Gh and IPumpMax. We hypothesize that myomodulin co‐modulates h‐ and pump currents to expand the domain of the functional activity.Support or Funding InformationSupported by NINDS 1 R01 NS085006 to RLC and 1 R21 NS111355 to RLC and GSC.

A novel memristor-based dynamical system with multi-wing attractors and symmetric periodic bursting.

This paper presents a novel memristor-based dynamical system with circuit implementation, which has a 2×3-wing, 2×2-wing, and 2×1-wing non-Shilnikov type of chaotic attractors. The system has two index-2 saddle-focus equilibria, symmetrical with respect to the x-axis. The system is analyzed with bifurcation diagrams and Lyapunov exponents, demonstrating its complex dynamical behaviors: the system reaches the chaotic state from the periodic state through alternating period-doubling bifurcations and then from the chaotic state back to the periodic state through inverse bifurcations, as one parameter changes. It shows two interesting phenomena: a jump-switching periodic state and jump-switching chaotic state. Also, the system can sustain chaos with a constant Lyapunov spectrum in some initial conditions and a parameter set. In addition, a class of symmetric periodic bursting phenomena is surprisingly observed under a particular set of parameters, and its generation mechanism is revealed through bifurcation analysis. Finally, the circuit implementation verifies the theoretical analysis and the jump-switching numerical simulation results.

Memristor Synapse-Based Morris–Lecar Model: Bifurcation Analyses and FPGA-Based Validations for Periodic and Chaotic Bursting/Spiking Firings

Electromagnetic induction current sensed by the membrane potential in biological neurons can be characterized with a memristor synapse, which can be employed to demonstrate the real oscillating voltage patterns of Barnacle muscle fibers. This paper presents a 3D autonomous memristor synapse-based Morris–Lecar (abbreviated as m-ML) model, which is implemented through introducing a memristor synapse-based induction current to substitute the externally applied current in an existing 2D nonautonomous Morris–Lecar model. Making use of one- and two-parameter bifurcation plots and time-domain representations, diverse period-adding bifurcations as well as abundant periodic and chaotic burst firings are demonstrated. Through constructing the fold and Hopf bifurcation sets of fast spiking subsystem, bifurcation analyses of these chaotic and periodic burst firings are carried out. Moreover, the periodic and chaotic spiking firings and coexisting firing behaviors are illustrated by using one- and two-parameter bifurcation plots and local attraction basins. Finally, based on a field programmable gate array (FPGA) board, a compact digital electronic neuron is fabricated for the 3D m-ML model, from which periodic and chaotic bursting/spiking firings are experimentally measured to verify the results of the numerical simulations.

Periodic Fast Radio Bursts from Young Neutron Stars

Abstract Fast radio bursts (FRBs) are highly energetic radio pulses from cosmological origins. Despite an abundance of detections, their nature remains elusive. At least a subset of FRBs is expected to repeat, as the volumetric FRB rate surpasses that of any known cataclysmic event, which has been confirmed by observations. One of the proposed mechanisms to generate repeating FRBs is supergiant pulses from young and highly spinning neutron stars (NSs), in which case FRBs could inherit the periodicity of their parent NS. Here we examine the consequences of such a population of periodic fast radio bursts (PFRBs). We calculate the rate and lifetime of PFRB progenitors, and find that each newly born highly spinning NS has to emit a number of detectable bursts during its active lifetime of yr, after which it becomes too dim and crosses a PFRB “death line” analogous to the pulsar one. We propose several tests of this hypothesis. First, the period of PFRBs would increase over time, and their luminosity would decrease, due to the NS spin-down. Second, PFRBs may show modest amounts of rotation measure, given the lack of expelled matter from the pulsar, as opposed to the magnetar-sourced FRBs proposed to explain the first repeater FRB 121102. As an example, we study whether the second confirmed repeater (FRB 180814) is a PFRB, given the preference for an inter-pulse separation of 13 ms within its sub-bursts. We show that, if confirmed, this period would place FRB 180814 in a different category as FRB 121102. We develop tests that would identify—and characterize—the prospective population of PFRBs.

Diagnostic Value of Electroencephalography with Ten Electrodes in Critically Ill Patients

BackgroundIn critical care settings, electroencephalography (EEG) with reduced number of electrodes (reduced montage EEG, rm-EEG) might be a timely alternative to the conventional full montage EEG (fm-EEG). However, past studies have reported variable accuracies for detecting seizures using rm-EEG. We hypothesized that the past studies did not distinguish between differences in sensitivity from differences in classification of EEG patterns by different readers. The goal of the present study was to revisit the diagnostic value of rm-EEG when confounding issues are accounted for.MethodsWe retrospectively collected 212 adult EEGs recorded at Massachusetts General Hospital and reviewed by two epileptologists with access to clinical, trending, and video information. In Phase I of the study, we re-configured the first 4 h of the EEGs in lateral circumferential montage with ten electrodes and asked new readers to interpret the EEGs without access to any other ancillary information. We compared their rating to the reading of hospital clinicians with access to ancillary information. In Phase II, we measured the accuracy of the same raters reading representative samples of the discordant EEGs in full and reduced configurations presented randomly by comparing their performance to majority consensus as the gold standard.ResultsOf the 95 EEGs without seizures in the selected fm-EEG, readers of rm-EEG identified 92 cases (97%) as having no seizure activity. Of 117 EEGs with “seizures” identified in the selected fm-EEG, none of the cases was labeled as normal on rm-EEG. Readers of rm-EEG reported pathological activity in 100% of cases, but labeled them as seizures (N = 77), rhythmic or periodic patterns (N = 24), epileptiform spikes (N = 7), or burst suppression (N = 6). When the same raters read representative epochs of the discordant EEG cases (N = 43) in both fm-EEG and rm-EEG configurations, we found high concordance (95%) and intra-rater agreement (93%) between fm-EEG and rm-EEG diagnoses.ConclusionsReduced EEG with ten electrodes in circumferential configuration preserves key features of the traditional EEG system. Discrepancies between rm-EEG and fm-EEG as reported in some of the past studies can be in part due to methodological factors such as choice of gold standard diagnosis, asymmetric access to ancillary clinical information, and inter-rater variability rather than detection failure of rm-EEG as a result of electrode reduction per se.