Spike recorded by multi-channel microelectrode array is very weak and susceptible to interference, whose noisy characteristic affects the accuracy of spike detection. Aiming at the independent white noise, correlation noise and colored noise in the process of spike detection, combining principal component analysis (PCA), wavelet analysis and adaptive time-frequency analysis, a new denoising method (PCWE) that combines PCA-wavelet (PCAW) and ensemble empirical mode decomposition is proposed. Firstly, the principal component was extracted and removed as correlation noise using PCA. Then the wavelet-threshold method was used to remove the independent white noise. Finally, EEMD was used to decompose the noise into the intrinsic modal function of each layer and remove the colored noise. The simulation results showed that PCWE can increase the signal-to-noise ratio by about 2.67 dB and decrease the standard deviation by about 0.4 μV, which apparently improved the accuracy of spike detection. The results of measured data showed that PCWE can increase the signal-to-noise ratio by about 1.33 dB and reduce the standard deviation by about 18.33 μV, which showed its good denoising performance. The results of this study suggests that PCWE can improve the reliability of spike signal and provide an accurate and effective spike denoising new method for the encoding and decoding of neural signal.
Both spike and local field potential (LFP) signals are two of the most important candidate signals for neural decoding. At present there are numerous studies on their decoding performance in mammals, but the decoding performance in birds is still not clear. We analyzed the decoding performance of both signals recorded from nidopallium caudolaterale area in six pigeons during the goal-directed decision-making task using the decoding algorithm combining leave-one-out and k-nearest neighbor (LOO-kNN). And the influence of the parameters, include the number of channels, the position and size of decoding window, and the nearest neighbor k value, on the decoding performance was also studied. The results in this study have shown that the two signals can effectively decode the movement intention of pigeons during the this task, but in contrast, the decoding performance of LFP signal is higher than that of spike signal and it is less affected by the number of channels. The best decoding window is in the second half of the goal-directed decision-making process, and the optimal decoding window size of LFP signal (0.3 s) is shorter than that of spike signal (1 s). For the LOO-kNN algorithm, the accuracy is inversely proportional to the k value. The smaller the k value is, the larger the accuracy of decoding is. The results in this study will help to parse the neural information processing mechanism of brain and also have reference value for brain-computer interface.
Transcranial magneto-acoustical stimulation (TMAS), utilizing focused ultrasound and a magnetostatic field to generate an electric current in tissue fluid to regulate the activities of neurons, has high spatial resolution and penetration depth. The neuronal spike-frequency adaptation plays an important role in the treatment of neural information. In this paper, we study the effects of ultrasonic intensity, magnetostatic field intensity and ultrasonic frequency on the neuronal spike-frequency adaptation based on the Ermentrout neuron model. The simulation results show that, the peak time interval becomes smaller, the interspike interval becomes shorter and the time of the firing of the neuron is shortened with the increasing of the magnetostatic field intensity. With the increase of the adaptive variables, the initial spike-frequency is shifted to the right with the magnetostatic field intensity, and the spike-frequency is linearly related to the increase of the magnetostatic field intensity in steady state. The simulation effect with change of the ultrasonic intensity is consistent with the change of magnetostatic field intensity. The change of the ultrasonic frequency has no effect on the neuronal spike-frequency adaptation. Under the different adaptive variables, with the increase of the adaptive variables, the initial spike-frequency amplitude decreased with the increasing of the ultrasonic frequency, and the spike-frequency is linearly related to the increase of the ultrasonic frequency in steady state. These results of the study can help us to reveal the mechanism of transcranial magneto-acoustical stimulation on the neuronal spike-frequency adaptation, and provide a theoretical basis for its application in the treatment of neurological disorders.
Deep brain stimulation (DBS), which usually utilizes high frequency stimulation (HFS) of electrical pulses, is effective for treating many brain disorders in clinic. Studying the dynamic response of downstream neurons to HFS and its time relationship with stimulus pulses can reveal important mechanisms of DBS and advance the development of new stimulation modes (e.g., closed-loop DBS). To exhibit the dynamic neuronal firing and its relationship with stimuli, we designed a two-dimensional raster plot to visualize neuronal activity during HFS (especially in the initial stage of HFS). Additionally, the influence of plot resolution on the visualization effect was investigated. The method was then validated by investigating the neuronal responses to the axonal HFS in the hippocampal CA1 region of rats. Results show that the new design of raster plot is able to illustrate the dynamics of indexes (such as phase-locked relationship and latency) of single unit activity (i.e., spikes) during periodic pulse stimulations. Furthermore, the plots can intuitively show changes of neuronal firing from the baseline before stimulation to the onset dynamics during stimulation, as well as other information including the silent period of spikes immediately following the end of HFS. In addition, by adjusting resolution, the raster plot can be adapted to a large range of firing rates for clear illustration of neuronal activity. The new raster plot can illustrate more information with a clearer image than a regular raster plot, and thereby provides a useful tool for studying neuronal behaviors during high-frequency stimulations in brain.
The rapid development of artificial intelligence put forward higher requirements for the computational speed, resource consumption and the biological interpretation of computational neuroscience. Spiking neuron networks can carry a large amount of information, and realize the imitation of brain information processing. However, its hardware is an important way to realize its powerful computing ability, and it is also a challenging technical problem. The memristor currently is the electronic devices that functions closest to the neuron synapse, and able to respond to spike voltage in a highly similar spike timing dependent plasticity (STDP) mechanism with a biological brain, and has become a research hotspot to construct spiking neuron networks hardware circuit in recent years. Through consulting the relevant literature at home and abroad, this paper has made a thorough understanding and introduction to the research work of the spiking neuron networks based on the memristor in recent years.
ObjectiveTo analyze the risk factors for electrical status epilepticus during sleep (ESES) in patients with self-limited epilepsy with centrotemporal spikes (SeLECTs) and to construct a nomogram model. MethodsThis study selected 174 children with SeLECTs who visited the Third Affiliated Hospital of Zhengzhou University from March 2017 to March 2024 and had complete case data as the research subjects. According to the results of video electroencephalogram monitoring during the course of the disease, the children were divided into non-ESES group (88 cases) and ESES group (86 cases). Multivariate logistic regression analysis was used to identify the risk factors for the occurrence of ESES in SeLECTs patients. ResultsThe multifactor Logistic regression analysis demonstrated that the EEG discharges in bilateral cerebral areas,types of seizure, epileptic seizures after initial treatment were the independent risk factors for the occurrence of ESES in SeLECTs. ConclusionBilateral distribution of electroencephalogram discharges before treatment, emergence of new seizure forms, and epileptic seizures after initial treatment are risk factors for the ESES in SeLECTs patients. The nomogram model constructed based on the above risk factors has a high degree of accuracy.
Anti-seizure medications (ASMs) are the most important and basic treatment for epilepsy, and are also the first choice for epilepsy treatment, but about one-third of patients have drug resistance. Perampanel (PER), as a novel third generation ASMs, inhibits the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) through non-competitive inhibition. AMPA plays an anti-seizure role. Since its approval in China in 2021, it has been mainly used in the treatment of focal epilepsy (with or without general seizure) as a single drug or addition, and has good safety, effectiveness and tolerability. Self-limited epilepsy with centrotemporal spikes (SeLECTS) is a common childhood focal epilepsy syndrome, accounting for 15% ~ 25% of various childhood epilepsies, PER has important advantages in clinical studies and has shown certain curative effect. At the same time, the overall effect of PER on cognition was neutral, with no systemic cognitive deterioration or improvement. In view of the relatively short application time of PER, which is still a new drug, this article will review the mechanism of action, dose, add-on (single drug) treatment, adverse events and, in order to provide clinicians with more drug choices and facilitate the individualized diagnosis and treatment of epilepsy.
ObjectiveTo investigate the efficacy and safety of Perampanel (PER) monotherapy in the treatment of self limited epilepsy with central temporal spikes (SeLECTS). Methods The clinical data of the first confirmed SelECTS in the outpatient and inpatient department of Xuzhou Children's Hospital affiliated to Xuzhou Medical University in December 2021 were collected, and the clinical data of PER monotherapy were retrospectively analyzed. The Seizure of 12 months old children were followed up to observe the efficacy and safety of PER monotherapy with spikes in the central temporal region, and the changes of Electroencephalography were observed. Result A total of 45 children with SeLECTS were included, of which 43 had complete medical records, including 13 males and 30 females, aged 4 ~ 14 years old, with a course of disease ranging from 1 month to 1.5 years. All 45 patients had focal seizures or focal secondary generalized tonic clonic seizures. Among them, 43 patients treated with PER alone for 12 months had epilepsy control efficacy rates of 74.41% (32/43) and no seizure rates of 60.46% (26/43), respectively. Seven children (15.56%, 7/45) experienced adverse reactions, characterized by dizziness, unstable gait, and irritability. Conclusion The third generation anti Seizure drug PER has a clear effect in the treatment of SelECTS, 2 ~ 4 mg PER can control Seizure well, and has no significant impact on cognitive development.
Recently a COVID-19 pneumonia pandemic caused by a novel coronavirus 2019-nCoV has broken out over the world. In order to better control the spread of the pandemic, there’s an urgent need to extensively study the virus’ origin and the mechanisms for its infectivity and pathogenicity. Spike protein is a special structural protein on the surface of coronavirus. It contains important information about the evolution of the virus and plays critical roles in the processes of cellular recognition and entry. In the past decades, spike protein has always been one of the most important objects in research works on coronaviruses closely related to human life. In this review we introduce these research works related to spike proteins, hoping it will provide reasonable ideas for the control of the current pandemic, as well as for the diagnosis and treatment of COVID-19.
Objective To identify clinical and electroencephalographic features of the variants of benign childhood epilespy with centrotemporal spikes (BECTs). Methods A total of 51 children with BECTs were restrospectively reviewed from July 2008 to December 2015 in the study, including the clinical data, electrophysiologic characteristics and effects of antiepileptic drugs. Results Age of the patients ranged from 2.5 to 11 years old, which were averged 7.03 years old. The duration of disease varied from 4 days to 6 years, and 2.36 years in average. Nearly continuous electric discharge were detected in slow sleeping, during which, the busting index was 90% in 19 patients’, 78% in 26, 52% in 6. the average busting index was 82.44%.47 patients (92.1%) had synptom of hand shaking; 8 patients(15.6%) had oropharyngeal automatism; 7 patients (13.7%) had language barrier; sample absence seizures or tumble occurred in 11 patients (21.5%); cognitive declined in 17 patients (33.3%). VPA monotherapy had good effect on 12 patients, 33 patients need combination of VPA and CBZ. However, there’s still 6 patients need adrenocortical hormone to control seizures. Conclusion The variants of BECT are companied with obvious deterioration of EEG. Lack of standard AED therapy may cause aggravations, so we need to monitor EEG closely. We use AED not merely in orde to control seizure but also inhibit abnormal EEG discharge.