Spike Duration Research Articles

Q-switched and noise-like mode-locked fiber laser based on ternary transition-metal carbide Nb2AlC saturable absorber

The saturable absorption of layered ternary transition-metal carbide (MAX) Nb2AlC is investigated in this work. Nb2AlC-based saturable absorber (SA) device is prepared and applied in an Er-doped fiber laser (EDFL). The EDFL can generate Q-switched and noise-like mode-locked pulses based on the excellent Nb2AlC SA. The EDFL operates in a Q-switched pulses mode state when the pump power is up to a threshold value of 50 mW. For the Q-switched pulse, the maximum single pulse energy is 66 nJ. The laser pulse generation mode switches to a noise-like mode-locked state when the pump power increases to 170 mW. The coherent spike duration is 2.8 ps and the corresponding maximum single pulse energy is 1.5 nJ at a pump power of 439 mW. A preliminary review of available literature indicates no reports of layered ternary carbide Nb2AlC as SA in an EDFL to generate switchable laser pulse modes. Results of this study suggest that ternary MAX Nb2AlC can be a remarkable nonlinear optical (NLO) device to explore switchable laser pulse generation modes and can encourage further studies on the ternary transition-metal carbides.

Artificial neurons based on antiferromagnetic auto-oscillators as a platform for neuromorphic computing

Spiking artificial neurons emulate the voltage spikes of biological neurons and constitute the building blocks of a new class of energy efficient, neuromorphic computing systems. Antiferromagnetic materials can, in theory, be used to construct spiking artificial neurons. When configured as a neuron, the magnetization in antiferromagnetic materials has an effective inertia that gives them intrinsic characteristics that closely resemble biological neurons, in contrast with conventional artificial spiking neurons. It is shown here that antiferromagnetic neurons have a spike duration on the order of picoseconds, a power consumption of about 10−3 pJ per synaptic operation, and built-in features that directly resemble biological neurons, including response latency, refraction, and inhibition. It is also demonstrated that antiferromagnetic neurons interconnected into physical neural networks can perform unidirectional data processing even for passive symmetrical interconnects. The flexibility of antiferromagnetic neurons is illustrated by simulations of simple neuromorphic circuits realizing Boolean logic gates and controllable memory loops.

Pneumonia in Children During the 2019 Outbreak in Xiamen, China.

To understand the regional epidemiology and clinical characteristics of adenovirus pneumonia in hospitalized children during the 2019 outbreak of respiratory adenoviruses in China. We analyzed the epidemiologic trend of adenovirus in children hospitalized for acute lower respiratory tract infections in Xiamen in 2019. Adenovirus was identified using direct fluorescent antibody detection. During the peak seasons of adenovirus epidemic, 170 adenovirus-positive specimens were obtained for molecular typing, and the clinical data were collected. Among the 9890 children hospitalized for acute lower respiratory tract infection, 609 (6.2%) were tested positive for adenovirus. The detection rate of adenovirus was significantly higher in boys than in grils (9.5% vs. 4.6%, P < 0.05). Adenovirus activity increased markedly between April and August with the prevalence of 7.3%-12.4%. During the outbreak season, type 7 accounted for 70.6%, followed by type 3 (28.8%) and type 4 (0.6%). Of the 155 cases of adenovirus pneumonia, the median age was 3.0 years (range: 4 month to 9 years), 153 (98.7%) had fever with a mean fever duration of 9.04 ± 5.52 days, 28 (16.5%) had wheezing, 93 (60%) showed segmental or lobar consolidation with atelectasis and 13 (8.4%) showed pleural effusion. Forty-six (29.6%) cases developed severe pneumonia, 7 (4.1%) required mechanical ventilation and 2 (1.2%) died. Younger age, longer duration of fever and higher fever spike were more frequently seen in severe cases (P < 0.05). Twenty-five (16.2%) had C-reactive protein ≥ 40 mg/L, and 91 (58.7%) had procalcitonin ≥ 0.25 mg/L. Adenovirus types 7 and 3 caused the outbreak of adenovirus pneumonia in community children during late spring to summer in 2019 in Xiamen. The majority of adenovirus pneumonia resembles bacterial pneumonia. The incidence of severe pneumonia was high when type 7 predominantly prevailed. Adenovirus type 7 was more common in severe cases than in nonsevere cases.

Dynamics of Electrical Resistance of Kombucha Zoogleal Mats

We demonstrate that zoogleal mats of kombucha exhibit spikes of electrical resistance. A kombucha is a sugared tea fermented by a symbiotic community of over 20 species of bacteria and yeasts which produce cellulosic gelatinous zoogleal mats. We recorded electrical resistance of the zoogleal mats via platinum electrodes placed at a distance 1 cm of each other. We found that the mats show temporal variations in electrical resistance in a range 0.13–0.19[Formula: see text]M[Formula: see text]. We discovered spikes of the mats resistance morphologically similar to action potential spikes. Average duration of a resistance spike is 1.8[Formula: see text]min, average amplitude is 2.2[Formula: see text]k[Formula: see text]. Average interval between resistance spikes is c. 20[Formula: see text]min. The discovered resistive spiking of kombucha mats might indicate on their memfractive properties, and thus, open pathways towards prototyping neuromorphic devices with living zoogleal mats.

Analysis Duration of Potential Difference Neutralizer for Substation Grounding System

The grounding system design of the 150 kV substation have resolve affect in lightning strike area. The purpose of this study is to determine the duration of the potential difference penetration that occurs due to direct or indirect lightning strikes. The parameter method grounding system uses a combination of R and L for the grid section and a combination of RLC for the rod section. Simulations due to direct lightning strikes in nearby areas greatly affect the spike in the amount of potential difference. The potential difference in the area closest to the lightning strike with a maximum surge of 57.42 V with a neutralization duration of 0.21 μs. At the furthest distance from a lightning strike, the maximum potential difference spike is only 3.14 V with a neutralization duration of 2 μs. The average duration of neutralization due to lightning strikes is 2 μs. In the simulation of a direct lightning strike striking electrical equipment, it causes a very high potential difference spike in lightning strike area of ​​992.96 V with a spike duration of 0.012 μs. The farthest area point at the location of the lightning strike has a spike of 31.07 V with a spike duration of 0.06 μs. The duration of neutralization at a potential difference below 1 V, has a duration of more than 2 μs depending on the distance from the location of lightning strike. The grounding system design is able to perform good performance with a fast potential difference neutralization duration in the event of a direct or indirect lightning strike. Lightning strikes that occur will not cause dangerous step and touch voltages for personnel in the 150 kV substation area.

Relationship between brain activity, cognitive function, and sleep spiking activation in new-onset self-limited epilepsy with centrotemporal spikes.

This study aimed to investigate the relationship between cognitive function sleep spiking activation and brain activity in self-limited epilepsy with centrotemporal spikes (SeLECTS). We used spike-wave index (SWI), which means the percentage of the spike and slow wave duration to the total non-REM (NREM) sleep time, as the grouping standard. A total of 14 children with SeLECTS (SWI ≥ 50%), 21 children with SeLECTS (SWI < 50%), and 20 healthy control children were recruited for this study. Cognitive function was evaluated using the Wechsler Intelligence Scale for Children, Fourth Edition (Chinese version) (WISC-IV). Magnetic source activity was assessed using magnetoencephalography calculated for each frequency band using the accumulated source imaging (ASI) technique. Children with SeLECTS (SWI ≥ 50%) had the lowest cognitive function scores, followed by those with SeLECTS (SWI < 50%) and then healthy controls. There were significant differences in the localization of magnetic source activity between the three groups: in the alpha (8-12 Hz) frequency band, children with SeLECTS (SWI ≥ 50%) showed deactivation of the medial frontal cortex (MFC) region; in the beta (12-30 Hz) frequency band, children with SeLECTS (SWI ≥ 50%) showed deactivation of the posterior cingulate cortex (PCC) segment; and in the gamma (30-80 Hz) frequency band, children in the healthy group showed activation of the PCC region. This study revealed significant decreases in cognitive function in children with SeLECTS (SWI ≥ 50%) compared to children with SeLECTS (SWI < 50%) and healthy children, as well as significant differences in magnetic source activity between the three groups. The findings suggest that deactivation of magnetic source activity in the PCC and MFC regions is the main cause of cognitive function decline in SeLECTS patients with some frequency dependence.

Can hyperoxic stress cause susceptibility to acute seizure in the neonatal period?: a rat study

Objective: Preterm neonates encounter hyperoxia relatively early, and are more exposed to hyperoxic stress due to their insufficient antioxidant defense mechanisms. This study was planned around the hypothesis that this hyperoxic effect may cause a disposition to future acute seizures. Methods: This study was composed of two main groups Hyperoxy and Control (Room air with normal O2 levels) Groups. Group 1 – hyperoxia (Study): The experimental group consisted of premature newborn rats exposed to hyperoxia with their dams from birth to postnatal day 5. Group 2 – room air (Control): The group was not exposed to hyperoxia and housed the same room air and temperature as their dams. Female, Acute Epilepsy Female, Male, Acute Epilepsy Male, and a total of eight subgroups were formed in both the control and hyperoxia groups. When the rats were two months old, intracranial electrodes were attached to obtain electrocorticography (ECoG) recordings. Pre-model recordings were taken, after which an acute pentylenetetrazole (PTZ) model of absence seizure was induced by the intraperitoneal administration of PTZ at 50 mg/kg. ECoG records were examined using the PowerLab system for 180 min. Spike wave number and duration, Spike wave frequency and amplitude data were evaluated.Results: Seven female and three male rats were exposed to hyperoxia, and a control group of five female and three male rats were included in the study. The median interquartile range for spike wave latency in the hyperoxia and control groups were 1112 (644–1545) and 654 (408–1152), frequency 4476 (3120–7421) and 3934 (2264–4704), and amplitude data 0.68 (0.59–0.79) and 0.52 (0.37–0.67), respectively. Although a difference was observed in median values capable of constituting susceptibility to epilepsy, the difference was not statistically significant (p > 0.05). In terms of gender, spike-wave counts were significantly higher in female rats (p < 0.05). Females exposed to hyperoxia were more susceptible to epilepsy than both males and females in the control group (p < 0.05).Conclusion: Exposure to hyperoxia in the first days of life of premature neonates due to their susceptibility to oxidative stress and insufficient antioxidant mechanisms, can cause a disposition to acute seizures. As a result, females exposed to hyperoxia during the neonatal period may be prone to epilepsy in maturity.

High-performance and -efficiency cardiomyocyte-based potential biosensor for temporal-specific detection of ion channel marine toxins

Paralytic shellfish toxins (e.g., saxitoxin, STX; gonyautoxin-2, GTX-2) and tetrodotoxin (TTX) are highly toxic and widely distributed ion channel marine toxins which specifically block the voltage-dependent sodium channels (VDSCs), causing great harm to human health. It is urgent to exploit new detection methods with high specificity and high efficiency. Here, a portable high-throughput cardiomyocyte-based potential biosensor was established with cardiomyocytes, a 16-well microelectrodes (MEs) sensor and a robust 32-channel recording system, which presented high-quality and high-consistency extracellular field potential (EFP) signals in each well with a long duration of 80 h. The feature parameters, including firing rate (FR), spike amplitude (SA), spike slope (SS), spike duration (SD) and field potential duration (FPD), were extracted from EFP to quantitatively assess the toxic effects of these ion channel toxins. Importantly, the biosensor showed temporal specificity and parametric selectivity under toxin treatments, and FR, SS and SD were the optimal parameters to STX, TTX and GTX-2, respectively. This biosensor can rapidly detect 0.29 ng/mL STX, 0.30 ng/mL TTX and 0.16 ng/mL GTX-2 within 5 min, 10 min and 15 min, respectively. Thus, our novel multi-well cardiomyocyte-based biosensor will be a promising tool for high-effective detection of ion channel toxins.

Wavelength-switchable noise-like square pulsed fiber laser based on nonlinear effects

We report a fiber laser that can generate switchable wavelength noise-like square pulses (NLSPs) with a tunable pulse width based on nonlinear effects and nonlinear polarization rotation (NPR) mode-locking technology. In the single-wavelength NLSP, the 3 dB bandwidth is 1.68 nm and the central wavelength is 1558.61 nm. The widths of the spike and pulse duration are 1.47 ps and 5.14 μs. In the case of obtaining dual-wavelength noise-like squares, the pulse width is broadened from 84.4 to 875.8 ns by varying the pump power in the range of 60 to 450 mW. The dual-wavelength square pulse has a maximum energy of 27.26 nJ. The phenomena investigated in this work are conducive to a profound understanding of NLSPs formation in fiber laser and are of great significance for broadening the approach for achieving multi-wavelength square pulse.

The Serotonin Transporter Modulates the Kinetics and Quantal Size of Vesicular Fusion Events in Sympathoadrenal Chromaffin Cells

The antidepressant‐sensitive serotonin transporter (SERT) is a key regulator of serotonin (5‐HT) signaling and availability in the CNS. The robust expression of SERT in adrenal chromaffin cells (ACCs), which comprise the neuroendocrine arm of the sympathetic nervous system, is less well understood. ACCs synthesize and secrete catecholamines (epinephrine, norepinephrine) which mediate the physiological response to stress. They do not synthesize 5‐HT, but do accumulate small amounts through SERT‐mediated uptake (5‐HT content is &lt;0.15% of the epinephrine content). We hypothesized that the chromaffin cells utilize this 5‐HT for autocrine / paracrine control of the sympathoadrenal stress response. Consistent with this hypothesis, we previously reported that 5‐HT1A receptors inhibit catecholamine secretion by reducing the number of secretory vesicles that fuse with the plasma. The objective of the current study was to investigate an additional, receptor‐independent mechanism by which SERT controls adrenal catecholamine secretion.We used carbon fiber amperometry to analyze catecholamine secretion from ACCs that were isolated from either wild type mice, global SERT‐knockout mice (SERT‐/‐), or sympathoadrenal system‐specific SERT knockout mice (SERTΔTH). Transmitter release from individual vesicle fusion events can be resolved as amperometric spikes. There was no difference in the number or time‐course of amperometric spikes evoked by 30mM KCl. The charge of the spikes is directly proportional to the amount of transmitter released by a single vesicle (i.e. quantal size). Spike charge was significantly smaller (~35%) and spike duration (half‐width) was significantly shorter in SERT‐knockout cells compared to matched controls. This was surprising given that HPLC analysis revealed no change in the catecholamine content of adrenal glands isolated from knockout mice compared to wild‐type controls; the 5‐HT content was significantly reduced but this accounted for &lt;0.15% of the total monoamine content. Changes in calcium entry can modulate the quantal size of catecholamine release in ACCs, but patch‐clamp recording revealed there was no significant difference in voltage‐gated calcium channel currents in SERT knockout cells and ratiometric calcium imaging found no difference in KCl‐evoked calcium entry. The decrease in quantal size was mimicked in wild‐type cells by treating for &gt;24 hours with escitalopram (an SSRI antidepressant which blocks SERT), or by depleting extracellular 5‐HT from the culture medium for &gt;24 hours (use of dialyzed serum in the culture media). In contrast, acute (minutes) or short‐term (&lt;6‐8 hrs) treatment with escitalopram or 5‐HT depletion had no effect. Adrenal chromaffin cells lack the rate limiting enzyme for 5‐HT synthesis (tryptophan hydroxylase), but if the product of this enzyme (5‐hydroxytryptophan; 5‐HTP) is provided it can be converted into 5‐HT. Treating ACCs with 5‐HTP for 1‐3 hrs had no effect but 24 hr treatment rescued the reduced spike charge seen in SERT knockout cells. Together, our data suggest that, following SERT‐mediated uptake, intracellular 5‐HT modulates the kinetics and thus fraction of secretory vesicle content that is released during a fusion event.

Single Particle Electrochemical Oxidation of Polyvinylpyrrolidone-Capped Silver Nanospheres, Nanocubes, and Nanoplates in Potassium Nitrate and Potassium Hydroxide Solutions

Single particle electrochemical oxidation of polyvinylpyrrolidone-capped silver nanoparticles at a microdisk electrode is investigated as a function of particle shape (spheres, cubes, and plates) in potassium nitrate and potassium hydroxide solutions. In potassium nitrate, extreme anodic potentials (≥1500 mV vs Ag/AgCl (3 M KCl)) are necessary to achieve oxidation, while lower anodic potentials are required in potassium hydroxide (≥900 mV vs Ag/AgCl (saturated KCl)). Upon oxidation, silver oxide is formed, readily catalyzing water oxidation, producing a spike-step current response. The spike duration for each particle is used to probe effects of particle shape on the oxidation mechanism, and is substantially shorter in nitrate solution at the large overpotentials than in hydroxide solution. The integration of current spikes indicates oxidation to a mixed-valence complex. In both electrolytes, the rate of silver oxidation strongly depends on silver content of the nanoparticles, rather than the shape-dependent variable–surface area. The step height, which reflects rate of water oxidation, also tracks the silver content more so than shape. The reactivity of less-protected citrate-capped particles toward silver oxidation is also compared with that of the polymer-capped particles under these anodic conditions in the nitrate and hydroxide solutions.

Noise-like pulse generation and amplification from soliton pulses.

The evolution of soliton pulses into noise-like pulses in a nonlinear fiber externally to the laser oscillator is demonstrated at 1.9 µm, for the first time. Soliton collapse based mechanisms induce noise-like pulses with varying properties as a function of nonlinear fiber length without requiring any laser cavity feedback. The proposed method allows the generation of noise-like pulses with a sub-300 fs spike and sub-40 ps pedestal duration. Power scaling of the noise-like pulses is demonstrated in a double-clad thulium-doped fiber amplifier with amplification up to an average power of 5.19 W, corresponding to a pulse energy of 244 nJ. This method provides an alternative route for generating fully synchronized noise-like pulses and solitons in the same system, without relying on the conventionally used mechanism of changing the intracavity nonlinearity within the laser cavity.

Language of fungi derived from their electrical spiking activity.

Fungi exhibit oscillations of extracellular electrical potential recorded via differential electrodes inserted into a substrate colonized by mycelium or directly into sporocarps. We analysed electrical activity of ghost fungi (Omphalotus nidiformis), Enoki fungi (Flammulina velutipes), split gill fungi (Schizophyllum commune) and caterpillar fungi (Cordyceps militaris). The spiking characteristics are species specific: a spike duration varies from 1 to 21 h and an amplitude from 0.03 to 2.1 mV. We found that spikes are often clustered into trains. Assuming that spikes of electrical activity are used by fungi to communicate and process information in mycelium networks, we group spikes into words and provide a linguistic and information complexity analysis of the fungal spiking activity. We demonstrate that distributions of fungal word lengths match that of human languages. We also construct algorithmic and Liz-Zempel complexity hierarchies of fungal sentences and show that species S. commune generate the most complex sentences.

Near-tendon single-fiber electromyography in patients with myopathy

We investigated how properties of single-fiber action potentials (SFAP) and jitter changed in different recording sites in patients with myopathy and controls. SFAP and jitter were recorded using a disposable single-fiber electrode in the biceps brachii muscle of three patients and controls in two sites: i) near the end-plate zone (EPZ), ii) near the tendon. SFAP and spike duration were longer in patients than in controls. Moving the needle away from the EPZ did not change the electrophysiologic parameters. Longer SFAP duration may reflect slow velocity in muscle fibers and serve as an indicator for small fiber size in myopathy.

Electrophysiological confrontation of Lead-DBS-based electrode localizations in patients with Parkinson’s disease undergoing deep brain stimulation

Microelectrode recordings (MERs) are often used during deep brain stimulation (DBS) surgeries to confirm the position of electrodes in patients with advanced Parkinson’s disease.The present study focused on 32 patients who had undergone DBS surgery for advanced Parkinson’s disease. The first objective was to confront the anatomical locations of intraoperative individual MERs as determined electrophysiologically with those determined postoperatively by image reconstructions. The second aim was to search for differences in cell characteristics among the three subthalamic nucleus (STN) subdivisions and between the STN and other identified subcortical structures.Using the DISTAL atlas implemented in the Lead-DBS image reconstruction toolbox, each MER location was determined postoperatively and attributed to specific anatomical structures (sensorimotor, associative or limbic STN; substantia nigra [SN], thalamus, nucleus reticularis polaris, zona incerta [ZI]). The STN dorsal borders determined intraoperatively from electrophysiology were then compared with the STN dorsal borders determined by the reconstructed images. Parameters of spike clusters (firing rates, amplitudes – with minimum amplitude of 60 μV -, spike durations, amplitude spectral density of β-oscillations) were compared between structures (ANOVAs on ranks).Two hundred and thirty one MERs were analyzed (144 in 34 STNs, 7 in 4 thalami, 5 in 4 ZIs, 34 in 10 SNs, 41 others). The average difference in depth of the electrophysiological dorsal STN entry in comparison with the STN entry obtained with Lead-DBS was found to be of 0.1 mm (standard deviation: 0.8 mm). All 12 analyzed MERs recorded above the electrophysiologically-determined STN entry were confirmed to be in the thalamus or zona incerta. All MERs electrophysiologically attributed to the SN were confirmed to belong to this nucleus. However, 6/34 MERs that were electrophysiologically attributed to the ventral STN were postoperatively reattributed to the SN. Furthermore, 44 MERs of 3 trajectories, which were intraoperatively attributed to the STN, were postoperatively reattributed to the pallidum or thalamus.MER parameters seemed to differ across the STN, with higher spike amplitudes (H = 10.64, p < 0.01) and less prevalent β-oscillations (H = 9.81, p < 0.01) in the limbic STN than in the sensorimotor and associative subdivisions. Some cells, especially in the SN, showed longer spikes with lower firing rates, in agreement with described characteristics of dopamine cells. However, these probabilistic electrophysiological signatures might become clinically less relevant with the development of image reconstruction tools, which deserve to be applied intraoperatively.

Synaptic Input and ACh Modulation Regulate Dendritic Ca2+ Spike Duration in Pyramidal Neurons, Directly Affecting Their Somatic Output.

Nonlinear synaptic integration in dendrites is a fundamental aspect of neural computation. One such key mechanism is the Ca2+ spike at the apical tuft of pyramidal neurons. Characterized by a plateau potential sustained for tens of milliseconds, the Ca2+ spike amplifies excitatory input, facilitates somatic action potentials (APs), and promotes synaptic plasticity. Despite its essential role, the mechanisms regulating it are largely unknown. Using a compartmental model of a layer 5 pyramidal cell (L5PC), we explored the plateau and termination phases of the Ca2+ spike under input current perturbations, long-step current-injections, and variations in the dendritic high-voltage-activated Ca2+ conductance (that occur during cholinergic modulation). We found that, surprisingly, timed excitatory input can shorten the Ca2+ spike duration while inhibitory input can either elongate or terminate it. A significant elongation also occurs when the high-voltage-activated Ca2+ channels (CaHVA) conductance is increased. To mechanistically understand these phenomena, we analyzed the currents involved in the spike. The plateau and termination phases are almost exclusively controlled by the CaHVA inward current and the Im outward K+ current. We reduced the full model to a single-compartment model that faithfully preserved the responses of the Ca2+ spike to interventions and consisted of two dynamic variables: the membrane potential and the K+-channel activation level. A phase-plane analysis of the reduced model provides testable predictions for modulating the Ca2+ spike and reveals various dynamical regimes that explain the robust nature of the spike. Regulating the duration of the Ca2+ spike significantly impacts the cell synaptic-plasticity window and, as we show, its input-output relationship.SIGNIFICANCE STATEMENT Pyramidal neurons are the cortex's principal projection neurons. In their apical tuft, dendritic Ca2+ spikes significantly impact information processing, synaptic plasticity, and the cell's input-output relationship. Therefore, it is essential to understand the mechanisms regulating them. Using a compartmental model of a layer 5 pyramidal cell (L5PC), we explored the Ca2+ spike responses to synaptic perturbations and cholinergic modulation. We showed a counterintuitive phenomenon: early excitatory input shortens the spike, whereas weak inhibition elongates it. Also, we demonstrated that acetylcholine (ACh) extends the spike. Through a reduced model containing only the membrane potential and the K+-channel activation level, we explained these phenomena using a phase-plane analysis. Our work provides new information about the robustness of the Ca2+ spike and its controlling mechanisms.

Synaptic Dynamics Convey Differential Sensitivity to Input Pattern Changes in Two Muscles Innervated by the Same Motor Neurons.

Postsynaptic responses depend on input patterns as well as short-term synaptic plasticity, summation, and postsynaptic membrane properties, but the interactions of those dynamics with realistic input patterns are not well understood. We recorded the responses of the two pyloric dilator (PD) muscles, cpv2a and cpv2b, that are innervated by and receive identical periodic bursting input from the same two motor neurons in the lobster Homarus americanusCpv2a and cpv2b showed quantitative differences in membrane nonlinearities and synaptic summation. At a short timescale, responses in both muscles were dominated by facilitation, albeit with different frequency and time dependence. Realistic burst stimulations revealed more substantial differences. Across bursts, cpv2a showed transient depression, whereas cpv2b showed transient facilitation. Steady-state responses to bursting input also differed substantially. Neither muscle had a monotonic dependence on frequency, but cpv2b showed particularly pronounced bandpass filtering. Cpv2a was sensitive to changes in both burst frequency and intra-burst spike frequency, whereas, despite its much slower responses, cpv2b was largely insensitive to changes in burst frequency. Cpv2a was sensitive to both burst duration and number of spikes per burst, whereas cpv2b was sensitive only to the former parameter. Neither muscle showed consistent sensitivity to changes in the overall spike interval structure, but cpv2b was surprisingly sensitive to changes in the first intervals in each burst, a parameter known to be regulated by dopamine (DA) modulation of spike propagation of the presynaptic axon. These findings highlight how seemingly minor circuit output changes mediated by neuromodulation could be read out differentially at the two synapses.

A Prospective Study of Intraocular Pressure Spike and Failure After Gonioscopy-Assisted Transluminal Trabeculotomy in Juvenile Open-Angle Glaucoma: A Prospective Study of GATT in JOAG

To identify risk factors for surgical failure after gonioscopy-assisted transluminal trabeculotomy (GATT) in juvenile open-angle glaucoma (JOAG). Prospective, interventional case series. GATT was the initial surgery in 70 eyes of 70 patients with JOAG. Surgical success was defined as a postoperative intraocular pressure (IOP) of ≤21 mm Hg with at least a 20% reduction from preoperative IOP, with or without the use of antiglaucoma medication (qualified and complete success, respectively) at each postoperative visit. IOP spike was defined as IOP >30 mm Hg and an increase of at least 10 mm Hg from IOP before the spike, and then reduced to ≤21 mm Hg. The median age at the time of surgery was 19.3 years (range, 4.9-37.5 years) with a visual field mean deviation of -17.4 ± 10.6 dB. Mean IOP decreased from 31.3 ± 9.5 mm Hg preoperatively to 15.8 ± 2.7 at 12 months postoperatively. The complete and qualified success rates were 74.3% and 91.4%, respectively. An IOP spike occurred in 52 eyes (74%), with a median spike duration of 3.5 days (range, 1-21 days). Longer duration of IOP spike (P=.009) and older age at the time of surgery (P=.025) were both associated with worse surgical outcomes. Advanced disease was associated with prolonged IOP spike (P=.007). GATT provided excellent outcomes in patients with severe JOAG. Older age and longer duration of postoperative IOP spike are risk factors for failure. Severe cases are more likely to have longer durations of IOP spike. Frequent IOP monitoring during the early postoperative period is needed to detect IOP spikes in these patients.

Discrimination between Inhibitory and Excitatory Neurons of Mouse Hippocampus Based on the Shape of Extracellular Spike Waveforms

Purpose: Inhibitory and excitatory neurons play an essential role in brain function, and we aim to introduce an automatic method to discriminate these two populations based on features of the shape of their spikes. Consequently, we will explain the spike extraction from raw data of a single shank electrode and determine the best features of spike waveforms for the classification of neurons. It is noteworthy that, to the best of our knowledge, classification of inhibitory and excitatory neurons using the shape features extracted from their spike waveforms has not been done before. Materials and Methods: In this paper, we use a dataset of mouse hippocampus neurons in which the neuron types (inhibitory or excitatory) have been verified optogenetically. For the classification of mouse hippocampus neurons, we extracted eight shape features of their spike waveforms in addition to their firing rates and used three types of classifiers: K-Nearest Neighbors (KNN), Linear Discriminant Analysis (LDA), and Support Vector Machine (SVM) to analyze the discriminatory power of features based on the accuracy of the classifications. Results: We showed that Spike asymmetry, Peak-to-trough ratio, Recovery slope, and Duration between peaks were four shape features of spike waveforms participated in the optimum feature subsets that resulted in maximum classification accuracy. Moreover, the SVM classifier with RBF kernel resulted in maximum accuracy of %96.91 ± %13.03 and was identified as the best classifier. Conclusion: In this study, we found that shape features of spike waveforms can accurately classify inhibitory and excitatory neurons of mouse hippocampus. Also, we found an optimum subset of shape features of spike waveforms that resulted in better classification performance than previously proposed subsets of features used for clustering of neurons. Our findings open a promising way toward a functional classification of neurons automatically.

Interface modification of Fe/Cr/Al magnetic multilayer by swift heavy ion irradiation

Interface mixing in [Fe/Cr/Al]x10 multilayer is studied under 120 MeV Ag9+swift heavy ions (SHIs) irradiation. The multilayers with different thicknesses were deposited using electron beam evaporation technique. The SHIs induced modifications in structural and magnetic properties were examined with X-ray reflectivity (XRR), magneto-optic Kerr effect (MOKE), and X-ray absorption fine structure (XAFS) to reveal interface diffusivity, including variation in magnetic coercivity, in-plane anisotropy, and local structure. The height of 1st order Bragg peak of XRR is used to determine the diffusion length as a function of ion fluence, and it is evident that the lower thickness of [Fe/Cr/Al]x10 multilayer possesses higher interface mixing as compared to samples with higher thickness. MOKE results confirm that both multilayers are soft magnetic in nature and show different behavior of in-plane anisotropy. With the SHIs irradiation, coercivity exhibits opposite trends for different thicknesses of Fe/Cr/Al multilayers due to different interface mixing. Fe K-edge XAFS is used for quantitative analysis of the Fe-Cr and Fe-Al phases as a function of multilayer thickness and ion fluence. The inelastic thermal spike (i-TS) model with size effect is used to explain the observed thickness-dependent intermixing due to the SHIs irradiation. The lattice temperature evaluation calculated by i-TS model shows longer spike duration in thinner film resulting in higher mixing.