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.
ObjectivesTo systematically review the efficacy of lidocaine injected prior to tracheal extubation in preventing hemodynamic responses to tracheal extubation in general anesthesia.MethodsPubMed, Ovid, Web of Science, EMbase, The Cochrane Library, CBM, CNKI, VIP and WanFang Data databases were electronically searched to collect randomized controlled trials (RCTs) on the efficacy of lidocaine administrated prior to extubation in preventing hemodynamic responses to tracheal extubation in patients undergoing general anesthesia from inception to October, 2018. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 and Stata 13.0 software.ResultsA total of 10 RCTs involving 525 patients were included. The results of meta-analysis showed that: compared with control group, lidocaine could reduce mean arterial pressure in 5 min after extubation (MD=–5.10, 95%CI –9.41 to –0.79, P=0.02), weaken the increase in systolic blood pressure caused by extubation from the moment before extubation to 5 minutes after extubation (before extubation: MD=–7.22, 95%CI –10.34 to –4.11, P<0.000 01; at extubation: MD=–14.02, 95%CI –19.42 to –8.62, P<0.000 01; 1 minutes after extubation: MD=–15.82, 95%CI –22.20 to –9.45, P<0.000 01; 3 minutes after extubation: MD=–12.55, 95%CI –20.36 to –4.74, P=0.002; and 5 minutes after extubation: MD=–12.05, 95%CI –20.35 to –3.74, P=0.004), and weakened extubation-induced increase in diastolic blood pressure at extubation (MD=–9.71, 95%CI –16.57 to –2.86, P=0.005). In addition, lidocaine inhibited heart rate in all time points except the moment of before and at 10 minutes after extubation.ConclusionsCurrent evidence shows that lidocaine can inhibit the increase in blood pressure and heart rate caused by extubation at certain times. Due to limited quality and quantity of the included studies, more high-quality studies are needed to verify above conclusions.