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.
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.
Epilepsy is characterized by abnormally synchronized firing of neuronal populations, which is presented as epileptiform spikes in neural electrical signal recordings. In order to investigate the epileptiform spikes quantitatively, we designed a new window-based algorithm to automatically detect population spikes (PS) in acute epilepsy models in rat hippocampus CA1 region, and to calculate characteristic parameters of PS. Results show that the algorithm could recognize PS waveforms directly in wideband recording signals in epilepsy models induced by 4-aminopyridine (4-AP), a potassium channel blocker, or by picrotoxin (PTX), an antagonist of γ-aminobutyric acid A-type receptor. The PS detection ratios of the two epilepsy models were 94.2%±1.6% (n=11) and 95.9%±1.9% (n=12), respectively. The false positive ratios were 3.5%±2.3% (n=11) and 4.8%±2.3% (n=12), which were significantly lower than those of the conventional threshold method. Comparisons of the PS patterns between the 4-AP model and the PTX model showed that the PS of the 4-AP model had wider waveforms and fired more dispersedly with intervals mainly in the range of 100–700 ms. The PS of the PTX model fired as Burst with a higher firing rate and with intervals mainly in the range of 2–20 ms, resulting in a larger sum of spike amplitudes per second than the 4-AP model. Thus, the synchronous firing of neuronal populations in the PTX model was more intense than that in the 4-AP model. In conclusion, the new algorithm of PS detection can correctly detect and analyze epileptiform population spikes. It provides a useful tool of data analysis for investigating the underlying mechanism of seizure generation and for evaluating new therapeutics of epilepsy.
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.
Deep brain stimulation (DBS) has been successfully used to treat a variety of brain diseases in clinic. Recent investigations have suggested that high frequency stimulation (HFS) of electrical pulses used by DBS might change pathological rhythms in action potential firing of neurons, which may be one of the important mechanisms of DBS therapy. However, experimental data are required to confirm the hypothesis. In the present study, 1 min of 100 Hz HFS was applied to the Schaffer collaterals of hippocampal CA1 region in anaesthetized rats. The changes of the rhythmic firing of action potentials from pyramidal cells and interneurons were investigated in the downstream CA1 region. The results showed that obvious θ rhythms were present in the field potential of CA1 region of the anesthetized rats. The θ rhythms were especially pronounced in the stratum radiatum. In addition, there was a phase-locking relationship between neuronal spikes and the θ rhythms. However, HFS trains significantly decreased the phase-locking values between the spikes of pyramidal cells and the θ rhythms in stratum radiatum from 0.36 ± 0.12 to 0.06 ± 0.04 (P < 0.001, paired t-test, N = 8). The phase-locking values of interneuron spikes were also decreased significantly from 0.27 ± 0.08 to 0.09 ± 0.05 (P < 0.01, paired t-test, N = 8). Similar changes were obtained in the phase-locking values between neuronal spikes and the θ rhythms in the pyramidal layer. These results suggested that axonal HFS could eliminate the phase-locking relationship between action potentials of neurons and θ rhythms thereby changing the rhythmic firing of downstream neurons. HFS induced conduction block in the axons might be one of the underlying mechanisms. The finding is important for further understanding the mechanisms of DBS.
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.
ObjectivesTo explore the characteristics of cognitive deficits of Benign epilepsy of childhood with centrotemporal spikes (BECTS).MethodsA total of 61 BECTS patients who visited Neurology Clinic of Xuanwu Hospital Capital Medical University between September 2010 to December 2019 and 60 healthy controls were enrolled in our study. All patients and healthy controls performed a series of neuropsychological tests to assess their cognitive function in the "Multi-dimensional psychology" of Beijing Normal University, including attention; memory; arithmetic calculation; language processing; executive function; visuospatial processing; visual perception; psychomotor speed. Lastly, independent sample t-test and friedman test were performed on the scores of BECTS group and controls using SPSS 20.0 and we conducted a multi-factor comprehensive analysis of correlation between clinical criteria and cognitive dysfunction in BECTS.ResultsCompared with 60 healthy controls, the as group got an average score of 19.56±2.91 in Paired Association Learning Test (P<0.001), (23.67±9.50) in Word Discrimination Test (P=0.017), (61.45±13.14) in Object Quantity Perception Task (P=0.040), (6.54±1.47) in Digit Span Test (P<0.001), (5.79±5.90) in Vocal Perception Test (P<0.001), (35.10±2.33) in Taylor Complex Figure Test (P<0.001) and (700.34±493.053) (P=0.008) in Choice Reaction Time Test. The results of these tests are inferior to the control group and the remaining 10 tests are of no statistical significance. There were 36 children with onset of seizure before 8 years of age. Compared with the patients experienced onset of illness at a later age, the 36 patients exhibited lower scores in most of the neuropsychological tests including Visual Tracking Task, Spatial Memory Task, Simple Subtraction Task, Number Comparison Test, Language Rhyme Test, Word Discrimination Testand Visual Perception Task (P<0.05). 34 patients received monotherapy, and 27 received a combination of 2 or 3 anti-epileptic drugs. The scores of attention, memory, visual perception and reaction tests in the multi drug treatment group were lower than those in the single drug treatment group (P<0.05).ConclusionsChildren with BECTS have impairment in attention, vocal perception, visual perception, memory and psychomotor speed. The younger the age of onset, the more severe the cognitive impairments. The degree of cognitive deficitsinchildren treated with multi drugs was more serious than that of children treated with single drugs.
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.
The measurement of network is one of the important researches in resolving neuronal population information processing mechanism using complex network theory. For the quantitative measurement problem of functional neural network, the relation between the measure indexes, i.e. the clustering coefficient, the global efficiency, the characteristic path length and the transitivity, and the network topology was analyzed. Then, the spike-based functional neural network was established and the simulation results showed that the measured network could represent the original neural connections among neurons. On the basis of the former work, the coding of functional neural network in nidopallium caudolaterale (NCL) about pigeon's motion behaviors was studied. We found that the NCL functional neural network effectively encoded the motion behaviors of the pigeon, and there were significant differences in four indexes among the left-turning, the forward and the right-turning. Overall, the establishment method of spike-based functional neural network is available and it is an effective tool to parse the brain information processing mechanism.
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.
