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.
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 evaluate the efficacy and safety of the third-generation super-mini percutaneous nephrolithotomy (SMP) for the treatment of kidney calculi with diameter of ≤2.5 cm and CT value of ≥700 Hu, and discuss the feasibility of adopting the technology in primary hospitals.MethodsThe clinical data of 64 patients with unilateral kidney calculi (CT value ≥700 Hu, diameter ≤2.5 cm) treated in the People’s Hospital of Leshan Central District between July 2017 and July 2018 were retrospectively analyzed. After random assignment, 30 patients were treated with SMP and 34 were with mini percutaneous nephrolithotomy (MPCNL). The pre-, intra-, and post-operative data were compared and analyzed to evaluate the efficacy and safety.ResultsThe unilateral lesion operations of both groups were successfully completed in the first phase. All patients were given double J tubes after operation, and there were no major complications such as post-operative hemorrhage and sepsis. There was no statistically significant difference in the post-operative hemoglobin decrease, post-operative immediate stone removal rate, post-operative stone removal rate after one month, or the rate of procalcitonin >0.1 μg/L between the two groups (P>0.05). The differences in the lithotripsy time [(29.63±6.28) vs. (25.21±5.19) minutes], post-operative hospital stay [(5.33±0.61) vs. (9.44±0.96) days], rate of indwelling renal fistula (3.3% vs. 50.0%), analgesic demand rate (10.0% vs. 58.8%), and postoperative infectious fever rate (6.7% vs. 26.5%) between SMP group and MPCNL group were statistically significant (P<0.05).ConclusionsSMP has the advantages of less trauma, low systemic inflammatory response syndrome incidence, less pain, quick rehabilitation, short hospital stay, tubeless after surgery, etc. It is worthy of extensive promotion in primary hospitals.