AB062. Cortical state contribution to neuronal response variability

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.

Interannual Changes of Land Surface Radiation Components in Loess Plateau and Their Responses to Climate Change

In this paper,land surface observation data at semi-arid climate and environmental observation station（ SACOL station） of Lanzhou University during 2006- 2012 and the data of Yuzhong meteorological station were used to analyze the responses of land surface radiation budget components to climate fluctuation,study the interannual variability of surface albedo,and discuss the feedback of various land surface process parameters on the interannual fluctuations of temperature and precipitation in Loess Plateau. According to the type of precipitation in Loess Plateau,the year was divided into winter and summer in order to get more significant interannual variability and correlation. The results showed that the trends of temperature and precipitation during 2006- 2012 were consistent with the warming and drying total trend in recent years in Loess Plateau. Shallow surface soil moisture and temperature showed a good response to temperature and precipitation,and the annual variation of summer half year had greater impact on the trend in the whole year. Incident solar radiation increase was major reason for climate warming in the Loess Plateau region.The combined effect of climatic factors was the reason for the change of surface albedo. Through the distinguish inquiry by winter and summer data,it was obtained that most correlations between summer radiation components and climatic factors have been improved,and partial correlations between winter radiation components and climatic factors have been increased.

Physical Parameter Identification Method Based on Modal Analysis for Two-axis On-road Vehicles:Theory and Simulation

Physical parameters are very important for vehicle dynamic modeling and analysis.However,most of physical parameter identification methods are assuming some physical parameters of vehicle are known,and the other unknown parameters can be identified.In order to identify physical parameters of vehicle in the case that all physical parameters are unknown,a methodology based on the State Variable Method（SVM） for physical parameter identification of two-axis on-road vehicle is presented.The modal parameters of the vehicle are identified by the SVM,furthermore,the physical parameters of the vehicle are estimated by least squares method.In numerical simulations,physical parameters of Ford Granada are chosen as parameters of vehicle model,and half-sine bump function is chosen to simulate tire stimulated by impulse excitation.The first numerical simulation shows that the present method can identify all of the physical parameters and the largest absolute value of percentage error of the identified physical parameter is 0.205%;and the effect of the errors of additional mass,structural parameter and measurement noise are discussed in the following simulations,the results shows that when signal contains 30 d B noise,the largest absolute value of percentage error of the identification is 3.78%.These simulations verify that the presented method is effective and accurate for physical parameter identification of two-axis on-road vehicles.The proposed methodology can identify all physical parameters of 7-DOF vehicle model by using free-decay responses of vehicle without need to assume some physical parameters are known.

Autonomic and cardiovascular effects of pentobarbital anesthesia during trigeminal stimulation in cats

Stimulation of the trigeminal nerve can elicit various cardiovascular and autonomic responses;however,the effects of anesthesia with pentobarbital sodium on these responses are unclear.Pentobarbital sodium was infused intravenously at a nominal rate and the lingual nerve was electrically stimulated at each infusion rate.Increases in systolic blood pressure（SBP） and heart rate（HR） were evoked by lingual nerve stimulation at an infusion rate between 5 and 7 mg？kg 21 ？h 21.This response was associated with an increase in the low-frequency band of SBP variability（SBP-LF）.As the infusion rate increased to 10 mg？kg 21 ？h 21 or more,decreases in SBP and HR were observed.This response was associated with the reduction of SBP-LF.In conclusion,lingual nerve stimulation has both sympathomimetic and sympathoinhibitory effects,depending on the depth of pentobarbital anesthesia.The reaction pattern seems to be closely related to the autonomic balance produced by pentobarbital anesthesia.

THERAPEUTIC EFFECT OF NON-SURGICAL TREATMENT OF CHRONIC PERIODONTITIS IN DIABETIC CHINESE

Objective To observe the therapeutic effect of non-surgical treatment on diabetic Chinese withchronic periodontitis. Methods Moderate to advanced chronic periodontitis ( CP) was studied in 36 diabetes mellitus (DM) patients classified as 20 with high and fluctuating blood glucose level (DM-H) and 16 with relatively low and stable blood glucose level (DM-L). 28 non-DM CP patients acted as controls (Non-DM). Plaque index (PlI) , gingival index (GI) , bleeding on probing (BOP) , probing depth (PD) and clinical attachment loss (AL) of all patients were recorded at 6 sites on each tooth at the baseline and 1, 3 and 6 months after oral hygiene instruction (OHI), scaling and root planing. Results It was found that the short-term effect of non-surgical periodon-tal procedure had resulted in significant resolution of gingival inflammation and pronounced reduction in pocket depth and gain of attachment loss in both DM and Non-DM CP patients. Conclusion The pilot study suggested that non-surgical periodontal treatment allowed for favorable treatment responses in a group of Chinese diabetic subjects with chronic periodontitis and that their various profiles of blood glucose did not influence the short-term healing response to OHI, scaling and root planning.

Disturbance response instability theory of rock bursts in coal mines and its application

Aiming at the rock burst prevention in coal mines,this study argue that a rock burst is the instability of the coal mass deformation system with the infinite deformation response subjected to a small disturbance,and the concepts of control,disturbance and response variables of the coal mass deformation system are proposed.The analytical solution of rock bursts of circular roadways is derived,using a mechanical model of the coal mass deformation system of circular roadways,and the stress and energy conditions of the disturbance response instability of a rock burst are also presented.Based on the disturbance response instability theory,this study identifies the factors controlling the occurrence of rock bursts,involving the coal uniaxial compressive strength,coal bursting liability and roadway support stress.The relationship between the critical stress and the critical resistance zone of surrounding rock in roadways,the coal uniaxial compressive strength,roadway support stress,roadway geometric parameters and coal burst liability is revealed,and the critical stress index evaluation method of rock burst risk is proposed.Considering the disturbance and response variables of rockburst occurrence,a monitoring system of rock burst based on stress and energy monitoring is established.Considering managing the disturbance and control variables,regional and local prevention measures of rock burst are proposed from four aspects:destressing in coal mass,avoiding the mutual disturbance between multi-group mining or excavation,reducing the dynamic load disturbance and weakening of the physical properties of the coal mass.Based on the enhancement principle of the roadway support stress on the critical load of rockburst occurrence and the energy absorption effect of the support,an energy absorption and anti-bursting support technology for roadways are proposed.The disturbance response instability theory of rock bursts has formed a technical system from the aspects of mechanism,prediction and prevention to guide the engineering practice for rock burst mitigation.

A fully on-chip fast-transient NMOS low dropout voltage regulator with quasi floating gate pass element

This paper presents a fully on-chip NMOS low-dropout regulator（LDO） for portable applications with quasi floating gate pass element and fast transient response.The quasi floating gate structure makes the gate of the NMOS transistor only periodically charged or refreshed by the charge pump,which allows the charge pump to be a small economical circuit with small silicon area.In addition,a variable reference circuit is introduced enlarging the dynamic range of error amplifier during load transient.The proposed LDO has been implemented in a 0.35 μm BCD process.From experimental results,the regulator can operate with a minimum dropout voltage of 250 mV at a maximum 1 A load and Iq of 395 μA.Under full-range load current step,the voltage undershoot and overshoot of the proposed LDO are reduced to 50 and 26 mV,respectively.