Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively esti...Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively estimate neuronal response variability,using multi-channel local field potential(LFP)data from single trials.Methods:Acute experiments were performed with anesthetized(Remifentanil,Propofol,nitrous oxide)and paralyzed(Gallamine Triethiodide)cats.Computer-controlled visual stimuli were displayed on a gamma-corrected CRT monitor.For the principal experiment,two kinds of visual stimuli were used:drifting sine-wave gratings,and a uniform mean-luminance gray screen.These two stimuli were each delivered monocularly for 100 sec in a random order,for 10 trials.Multi-unit activity(MUA)and LFP signals were extracted from broadband raw data acquired from Area 17 and 18 using A1X32 linear arrays(NeuroNexus)and the OpenEphys recording system.LFP signal processing was performed using Chronux,an open-source MATLAB toolbox.Current source density(CSD)analysis was performed on responses to briefly flashed full-field stimuli using the MATLAB toolbox,CSDplotter.The common response variability(global noise)of MUA was estimated using the model proposed by Scholvinck et al.[2015].Results:On different trials,a given neuron responded with different firing to the same visual stimuli.Within one trial,a neuron’s firing rate also fluctuated across successive cycles of a drifting grating.When the animal was given extra anesthesia,neurons fired in a desynchronized pattern;with lighter levels of anesthesia,neuronal firing because more synchronized.By examining the cross-correlations of LFP signals recorded from different cortical layers,we found LFP signals could be divided to two groups:those recorded in layer IV and above,and those from layers V and VI.Within each group,LFP signals recorded by different channels are highly correlated.These two groups were observed in lighter and deeper anesthetized animals,also in sine-wave and uniform gray stimulus conditions.We also investigated correlations between LFP signals and global noise.Power in the LFP beta band was highly correlated with global noise,when animals were in deeper anesthesia.Conclusions:Brain states contribute to variations in neuronal responses.Raw LFP correlation results suggest that we should analyze LFP data according to their laminar organization.Correlation of low-frequency LFP under deeper anesthesia with global noise gives us some insight to predict noise from single-trial data,and we hope to extend this analysis to lighter anesthesia in the future.展开更多
目的·探讨使用程序化麻醉下手法松解术(manipulation under anesthesia,MUA)治疗膝关节创伤术后关节粘连的临床疗效及安全性。方法·入选21例膝关节创伤术后关节粘连患者(包括膝关节多韧带损伤重建和/或修补术后6例、膝关节周...目的·探讨使用程序化麻醉下手法松解术(manipulation under anesthesia,MUA)治疗膝关节创伤术后关节粘连的临床疗效及安全性。方法·入选21例膝关节创伤术后关节粘连患者(包括膝关节多韧带损伤重建和/或修补术后6例、膝关节周围骨折内固定术后9例、髌骨脱位术后6例),行程序化MUA。使用关节量角尺评估患者在程序化MUA前、中、后随访(2周、12周、24周)的屈膝角度;使用视觉模拟评分法(visual analogue scale,VAS)评估患者在程序化MUA后2周内的疼痛程度;记录患者于程序化MUA中、后可能出现的并发症。结果·程序化MUA前、中、后随访(2周、12周、24周),患者的平均屈膝角度分别为73.8°、119.3°、101.7°、122.5°、127.4°。与术前相比,程序化MUA后24周的平均屈膝角度增加了53.6°。VAS评估结果显示,患者仅在术后1~3 d活动状态下的评分超过4分。术中及术后均未有并发症发生。结论·程序化MUA治疗膝关节创伤后关节粘连相对安全且有效。展开更多
研究并设计了电子邮件MUA(Mail User Agent,邮件用户代理)软件模块,给出了实现电子邮件数据流处理及通讯协议实现的具体细节。该模块严格遵循RFC文档,融合服务器认证过程,可以接入Internet上规范的邮件服务器;提供丰富的程序接口,可作...研究并设计了电子邮件MUA(Mail User Agent,邮件用户代理)软件模块,给出了实现电子邮件数据流处理及通讯协议实现的具体细节。该模块严格遵循RFC文档,融合服务器认证过程,可以接入Internet上规范的邮件服务器;提供丰富的程序接口,可作为应用系统中的一个通讯模块使用。展开更多
文摘Background:Visual cortex neurons often respond to stimuli very differently on repeated trials.This trial-by-trial variability is known to be correlated among nearby neurons.Our long-term goal is to quantitatively estimate neuronal response variability,using multi-channel local field potential(LFP)data from single trials.Methods:Acute experiments were performed with anesthetized(Remifentanil,Propofol,nitrous oxide)and paralyzed(Gallamine Triethiodide)cats.Computer-controlled visual stimuli were displayed on a gamma-corrected CRT monitor.For the principal experiment,two kinds of visual stimuli were used:drifting sine-wave gratings,and a uniform mean-luminance gray screen.These two stimuli were each delivered monocularly for 100 sec in a random order,for 10 trials.Multi-unit activity(MUA)and LFP signals were extracted from broadband raw data acquired from Area 17 and 18 using A1X32 linear arrays(NeuroNexus)and the OpenEphys recording system.LFP signal processing was performed using Chronux,an open-source MATLAB toolbox.Current source density(CSD)analysis was performed on responses to briefly flashed full-field stimuli using the MATLAB toolbox,CSDplotter.The common response variability(global noise)of MUA was estimated using the model proposed by Scholvinck et al.[2015].Results:On different trials,a given neuron responded with different firing to the same visual stimuli.Within one trial,a neuron’s firing rate also fluctuated across successive cycles of a drifting grating.When the animal was given extra anesthesia,neurons fired in a desynchronized pattern;with lighter levels of anesthesia,neuronal firing because more synchronized.By examining the cross-correlations of LFP signals recorded from different cortical layers,we found LFP signals could be divided to two groups:those recorded in layer IV and above,and those from layers V and VI.Within each group,LFP signals recorded by different channels are highly correlated.These two groups were observed in lighter and deeper anesthetized animals,also in sine-wave and uniform gray stimulus conditions.We also investigated correlations between LFP signals and global noise.Power in the LFP beta band was highly correlated with global noise,when animals were in deeper anesthesia.Conclusions:Brain states contribute to variations in neuronal responses.Raw LFP correlation results suggest that we should analyze LFP data according to their laminar organization.Correlation of low-frequency LFP under deeper anesthesia with global noise gives us some insight to predict noise from single-trial data,and we hope to extend this analysis to lighter anesthesia in the future.
