The core problem of the brain-computer interface (BCI) based on neural signal is estimating neural firing rate from a spike train and then using neural population decoding algorithm to decode movement trajectory.In this artical, we review the theoretical basis of both classic and current firing rate estimations and compare the advantages and drawbacks of these methods. At the same time we also review the decoding algorithm which using neural firing rate to decode movement trajectory in brain- computer interface: population vector algorithm, linear filter and kalman filter. At last, some results applying these estimators of firing rate to decode arm movement in BCI are introduced. The results show apparently different performance of the different firing rate estimators, while minimal differences are observed in the actual application of BCI.

AIM: To investigate the role of NFAT in cyclosporine A downregulating IFN-? gene transcription after liver transplantation. METHODS: Rat orthotopic liver transplantation model was employed and 3 groups of experiments were performed in this study. GroupⅠ: syngeneic control (Wistar-to-Wistar); GroupⅡ: acute rejection (SD-to-Wistar). GroupⅢ: acute rejection treated with cyclosporine A intramuscularly (SD-to-Wistar+CsA). EMSA and RT-PCR were used to analyze NFAT activity of splenocytes and IFN-? gene transcription intragraft of recipients with or without CsA treatment after liver transplantation. Histopathological assessment was also performed for reference. RESULTS: No noticeable rejection was detected in GroupⅠ while only low level of IFN-? mRNA transcription and faint NFAT activity were measured. In contrast, a marked rejection reaction was demonstrated from day3 postoperation in GroupⅡ. IFN-? mRNA transcription was significant and NFAT activity was intensive. In comparison to GroupⅡ, rejection grade in Group Ⅲ significantly decreased (P

Aiming at local field potential, the present paper introduces a method of estimating lag of neuron activities between brain areas based on windowed Harmonic wavelet transform (WHWT). Firstly, the WHWT of signals of two brain areas are calculated. Secondly, the instantaneous amplitude of the signals is calculated and finally, these amplitudes are cross-correlated and the lag at which the cross-correlation peak occurs is determined as the lag of neurons activities. Comparing with amplitude cross-correlation based on Gabor wavelet transform (GWT) or Hilbert transform (HT), this method is more precise and efficient in estimating the directionality and lag.
Brain ; physiology ; Humans ; Neurons ; physiology ; Wavelet Analysis

ObjectiveTo investigate the mechanism by which cyclosporine A downregulates transcription of interferon-? gene after murine orthotopic liver transplantation.Methods Orthotopic murine liver transplantation model was employed and rats were divided into 3 groups. GroupⅠ: syngeneic control (Wistar-to-Wistar); GroupⅡ: acute rejection (SD-to-Wistar). GroupⅢ: acute rejection treated with cyclosporine A (SD-to-Wistar+CsA). EMSA was employed to analyze NFAT and NF-?B DNA-binding activity of splenocytes, RT-PCR was employed to analyze IFN-? mRNA transcription intragraft on 1,3,5,7,12 day posttransplant in each group, respectively. Histopathological examination was also performed for reference.Results In comparison to groupⅠ, NFAT and NF-?B DNA-binding activity of splenocytes in groupⅡincreased significantly( P

Objective To study the role of 1,25-dihydroxyvitamin D3 in preventing allograft acute rejection in rat orthotopic liver transplantation. Method Rats receiving orthotopic liver transplantation were divided into groupⅠ: syngenic control (Wistar-to-Wistar); GroupⅡ:acute rejection (SD-to-Wistar). GroupⅢ: acute rejection treated with cyclosporine; GroupⅣ: acute rejection treated with 1,25-(OH)_ 2 D_ 3 . Liver function, rejection index and IFN-? mRNA, IL-10 mRNA expression level were monitored on d1,5,7,15,30 posttransplantation. Results Survival of recipients in group Ⅳ was significantly prolonged (vs group Ⅱ, P

Objective To investigate the role of B7/CD28 costimulation pathway blockade with adenovirus-mediated CTLA4-Ig gene in macrophage and CD8~+T cell infiltration and cell apoptosis in murine liver transplantation. Methods Rat pairs were divided into three groups: SD-to-Wistar transplantation control group, CsA-treated group and CTLA4-Ig-treated group. IHC and TUNEL were used to analyze the expression of CTLA4-Ig gene in liver and immune cells infiltrate and cell apoptosis in liver grafts. Pathology was done on all harvested grafts. ResultsCTLA4-Ig gene expression was positive in the donor liver on day 7 after administering adenovirus-mediated CTLA4-Ig gene via vein, and remained positive until day 60 after liver transplantation. Infiltration of immune cells in CTLA4-Ig-treated group was less than that in rejection control group. the apoptotic index of rejection group on day 3,5,7 was significantly higher than those of CTLA4-Ig-treated. Conclusions CTLA4-Ig gene was constantly expressed in the donor liver after single intravenousely injection into rats using adenovirus as vector. Adenovirus-mediated CTLA4-Ig gene therapy can inhibit infiltration of immune cells and apoptosis in grafts, thus prolonging the survival of recipients.

We have brought forward a wavelet-based algorithm for electroencephalograph (EEG) signals--using scale dependent threshold based on median. In comparison with the universal threshold and Sure threshold, our proposed threshold, which is adaptive to the subband noise signals, preserves the noise free reconstruction property and takes lower risk than does the universal threshold; and our proposed threshold overcomes the drawback of Sure threshold. Evidently, the scale dependent threshold based on median is computationally simple and can obtain higher singal-to-noise ratio (SNR) it outperforms the universal threshold and Sure threshlold.
Algorithms ; Artifacts ; Electroencephalography ; Humans ; Signal Processing, Computer-Assisted

Recording and extracting characteristic brain signals in freely moving animals is the basic and significant requirement in the study of brain-computer interface (BCI). To record animal's behaving and extract characteristic brain signals simultaneously could help understand the complex behavior of neural ensembles. Here, a system was established to record and analyse extracellular discharge in freely moving rats for the study of BCI. It comprised microelectrode and micro-driver assembly, analog front end (AFE), programmer system on chip (PSoC), wireless communication and the LabVIEW used as the platform for the graphic user interface.
Animals ; Behavior, Animal ; physiology ; Brain ; physiology ; Electroencephalography ; methods ; Microelectrodes ; Rats ; Signal Processing, Computer-Assisted ; instrumentation ; Telemetry ; instrumentation ; User-Computer Interface