Guest Editorial Brain-Computer Interface： Today and Tomorrow

As the invited editor of this special issue on braincomputer interface （BCI）, I am pleased to give a comment on the state-of-the-art with the introduction of recent advances made at the Chengdu BCI Group, University of Electronic Science and Technology of China （UESTC）.     

Real-Time Brain-Computer Interface System Based on Motor Imagery

Abstract-A brain-computer interface （BCI） real- time system based on motor imagery translates the user＇s motor intention into a real-time control signal for peripheral equipments. A key problem to be solved for practical applications is real-time data collection and processing. In this paper, a real-time BCI system is implemented on computer with electroencephalogram amplifier. In our implementation, the on-line voting method is adopted for feedback control strategy, and the voting results are used to control the cursor horizontal movement. Three subjects take part in the experiment. The results indicate that the best accuracy is 90%.     

直接脑控机器人接口技术

在现代化科学技术发展带动作用下,作为一种新兴的人-机器人接口技术—直接脑控机器人技术成为了当下机器人控制研究领域的重要研究内容之一。文章首先对脑控机器人接口内容进行了详细的论述,并对BCRI关键技术之一进行了分析,已为今后直接脑控机器人接口技术参考使用。     

脑机接口信号处理的研究进展

目前,神经电刺激领域发展较为迅速,主要应用领域是对脑部核团进行电刺激,用于治疗或缓解患者相关病症,主要调整参数方式为主观调节,医生根据患者情况进行参数调节,让患者感受相关刺激后决定是否采用该参数,存在调整不精准、不适应、不及时等情况.随着市场需求增加,通信技术发展,远程医疗逐渐能够解决程控调整的及时性问题,但更本质的解...     

PEB模型在同步核磁-脑电源定位中的应用

利用脑电(Electroencephalographic,EEG)和功能性磁共振成像(functional Magnetic Resonance Imaging,fMRI)时间和空间上的互补性可以获得大脑的电源活动。为了获得经典奖惩任务中脑区的激活情况,同步采集fMRI-EEG数据,使用以fMRI空间作为约束的参数经验贝叶斯(Parametric Empirical Bayesian,PEB)模型进行了脑电源活动分析。同时,结合稀疏求解的方法,提取更集中的神经电活动,进一步突出激活强度高的脑区。实验结果表明,在奖惩结果呈现后的200～350 ms内,奖赏刺激能够诱发出反馈相关负波(Feedback Related Negativity,FRN)。fMRI空间定位显示前额叶、眶额叶等奖赏相关脑区出现激活,EEG源定位提取到了前额叶脑区的激活,但是这些激活区域均分散在脑区的各个部位。相比于单一模态fMRI空间定位和EEG源定位结果,同步源定位提取的脑区更集中,获得的模型证据也更大,更准确地描绘了脑区激活情况。     

高灵敏度多通道fNIRS系统的BCI应用：“肯定/否定”二分类意图识别

本文探讨了高灵敏度多通道fNIRS系统用于解码“肯定/否定”二分类意图的脑机接口应用。实验过程中采用全并行激励下的锁相光子计数模式进行测量,采集了10名被试思考针对其个人情况的相关问题时前额叶脑区的fNIRS信号,从中提取血红蛋白浓度变化数据的均值、方差、偏度、峰度、激活水平这五种特征,根据各特征对不同被试的分类效果和Fisher-score方法分别进行特征与通道选择,并最终构建支持向量机(SVM)模型。采用10次十折交叉方案进行验证,以更好地评估模型的分类准确性。为了对比,本文也研究了以原始光强数据建立的SVM模型的分类效果。实验结果表明：使用血红蛋白浓度变化数据构建的SVM模型的平均平衡准确率为73.1%±1.7%,以原始光强数据构建的SVM模型的平均平衡准确率为70.6%±3.7%,前者较后者提高了3.5%,且二者的平均平衡准确率均达到了70%以上。本研究不但展示了高灵敏度多通道fNIRS系统识别人脑直接意图的能力,也为fNIRS-BCI的应用提供了有益思路。     

A Study on SSVEP-Based BCI

Abstract-Brain-computer interface （BCI） can help the deformity person finish some basic activities. In this paper, we concern some critical aspects of SSVEP based BCI, including stimulator selection, method of SSVEP extracting in a short time, stimulating frequency selection, and signal electrode selection. The conclusion is that the stimulator type should be based on the complexity of the BCI system, the method based on wavelet analysis is more valid than the power spectrum method in extracting the SSVEP in a short period, and the selections of stimulating frequency and electrode are important in designing a BCI system. These contents are meaningful for implementing a real SSVEP-based BCI.     

专利视角下植入式脑机接口电极技术发展趋势分析

植入式脑机接口电极对神经疾病的诊断、预警和治疗以及脑科学研究具有重要意义。从专利视角回顾和研判了植入式电极的全球技术发展趋势,研究了生物相容性、信号质量提升的最新技术解决思路;并呼吁我国政府加大在植入式电极领域的研发投入力度,以及加强对先进制造工艺和材料技术的关注,加快推动植入式电极成熟落地应用和完善专利布局。     

便携式脑电信号采集与分析装置的设计及其应用

文中设计一套应用于自由活动动物脑电信号采集与分析的便携式装置,这种体积小、重量轻、实时检测的装置可以采集与分析自由活动大鼠运动行为的脑电信号,进而研究特定动物的运动行为与脑部电信号之间的对应关系。首先将微电极植入大鼠特定大脑皮层,通过模拟电路采集来自微电极的脑电信号,经过滤波、放大,调理后进入片上可编程系统PSoC并进行数据的模拟转换和处理,再通过无线USB模块进行实时传输数据至PC端,最后在LabVIEW界面下实现实时分析并显示动物脑区局部场电位。该研究为多方面、多角度和多层次的研究大脑复杂性和未知性提供小型化设备平台。     

Semi-Supervised Learning Based on Manifold in BCI

Abstract-A Laplacian support vector machine （LapSVM） algorithm, a semi-supervised learning based on manifold, is introduced to brain-computer interface （BCI） to raise the classification precision and reduce the subjects＇ training complexity. The data are collected from three subjects in a three-task mental imagery experiment. LapSVM and transductive SVM （TSVM） are trained with a few labeled samples and a large number of unlabeled samples. The results confirm that LapSVM has a much better classification than TSVM.     

fMRI-BCI: a Review

Functional magnetic resonance imaging (fMRI) is a new tool for brain-computer interface (BCI). This paper presents an overview to fMRI-BCI. Our attention is mainly put on the methods of signal acquisition, signal preprocessing, and signal analysis of basic fMRI-BCI structure. The available softwares and the applications of fMRI-BCI are briefly introduced. At last, we suggest focusing on some technologies to make fMRI-BCI more perfect.     

基于多FPGA的SAR成像信号处理机设计

文中针对FPGA在数字信号处理领域中一些区别于DSP的优点,以及SAR信号仿真与处理的大运算量、高数据通信量和实时性对成像处理机的可靠性和稳定性等特点,设计开发了一种基于多FPGA的SAR成像信号处理机。详细介绍了系统结构、数据通信方式以及FPGA配置等关键问题。     

Two Dimensional Spatial Independent Component Analysis and Its Application in fMRI Data Process

One important application of independent component analysis （ICA） is in image processing. A two dimensional （2-D） composite ICA algorithm framework for 2-D image independent component analysis （2-D ICA） is proposed. The 2-D nature of the algorithm provides it an advantage of circumventing the roundabout transforming procedures between two dimensional （2-D） image deta and one-dimensional （l-D） signal. Moreover the combination of the Newton （fixed-point algorithm） and natural gradient algorithms in this composite algorithm increases its efficiency and robustness. The convincing results of a successful example in functional magnetic resonance imaging （fMRI） show the potential application of composite 2-D ICA in the brain activity detection.     

一种距离高分辨力雷达实时信号处理机的设计与实现

现代高性能的雷达系统对雷达信号处理系统的计算能力、存储能力以及传输能力等提出了更高的要求。以多片高性能的数字信号处理器(DSP)为运算核心,通过高速数据连接网络构成的并行信号处理系统能够满足系统的高速复杂的运算以及大的数据吞吐量的要求。本文在详细分析某型距离高分辨力雷达信号处理机的需求的基础上,提出了适合该雷达信号处理机的系统结构,并采用8片ADI的超高性能浮点DSP芯片—ADSP-TS201S为核心设计并实现了一种高速实时并行信号处理机。该处理机的设计充分考虑了雷达实时信号处理的特点,遵循可编程、可扩展、可重构的原则,为系统性能的提升提供了较大的空间,并可用来构造多种不同需求的雷达信号处理系统。目前,该信号处理机已经调试成功并通过了外场试验。     

基于小波变换和空间相关性fMRI数据

提出了一种组合小波域统计分析和空间相关性检验的方法来检测fMRI功能激活区域.该方法首先利用Ruttimann等提出的小波方法检测到激活体素,然后逐体素分析它们与其三维空间26-邻域体素血流动力学响应的相关性,并进行空间相关性检验来得到最终激活区域.实验结果表明:该方法是一种快速可靠的fMRI功能激活区域检测方法.     

一种机载SAR实时成像信号处理系统的设计

提出了一种基于VME总线的机载SAR实时成像信号处理系统的设计方案。方案充分考虑了SAR实时成像所需的数据处理能力和传输带宽，在硬件设计上采用了由多片DSP组成的紧耦合分布式并行处理结构，有效地解决了大量数据传输带来的数据瓶颈问题。同时结合具体的成像算法，给出了详细的软件设计流程。     

Study on the Location of the Activated Cerebellum Regions in Manual Movement Related to Handedness

The present study used functional magnetic resonance imaging(fMRI)to study the activated site in the cerebellum during bi-hand movement and uni-hand movement,and the lateralization of the cerebellum in hand movement.The coordinates of the peak activation in the CRB were compared using statistical tests,and the results in the primary motor cortex(PMC)were presented as comparison.The results showed a significant difference in cerebellum during bi-hand movement comparing the right-handed with the left-handed subjects.When comparing the right-handed subjects and left-handed subjects during right-hand movement,the significantly different coordinate in dorsal/ventral orientation was observed.The results also showed the different activated site during bi-hand movement and non-dominant hand movement.Our study took the point of view of the lateralization in cerebellum,and the results demonstrated the different site of the peak activation in cerebellum during bi-hand movement and uni-hand movement,which suggested that the handedness also existed in the cerebellum.     

Abnormal Basal Ganglia Functional Connectivity in Idiopathic Generalized Epilepsy

The basal ganglia have been implicated in a modulation role in idiopathic generalized epilepsy (IGE) by an invasive electrophysioigic means.This paper investigates the basal ganglia functional connectivity by using the region-wise functional connection analysis in resting-state functional magnetic resonance imaging (fMRi) in IGE.The increased functional connectivity within basal ganglia,and between the basal ganglia and the thalamus,and decreased functional connectivity between basal ganglia and motor cortex are found in IGE compared with the controls. These findings not only implicate dysfunctional integration in the motor loop in IGE and the enhanced interaction in the modulated loop,but also suggest that the basal ganglia modulate the generalized epileptic discharges with the influence over thalamus in the corticothalamus network.     

Listen to the Brain in Real Time-The Chengdu Brainwave Music

Electroencephalogram (EEG) provides a window for the activity of the human brain. As a novel form of the brain-computer interface (BCI), the online/offline EEG data may be interpreted through its auditory representation which can be considered as a specific tool in EEG monitoring and analysis. In this work, after a comprehensive comparison of the various designs of brainwave music generations, a waveform event mapping system for music display in real time-the Chengdu Brainwave Music (CBM) is proposed, which is a special on-line BCI system. In CBM, the user datagram protocol (UDP) is adopted to transport EEG data from the recorder to a music generator. The CBM could possibly be used as an audio feedback tool in BCI, or a monitoring tool in clinic EEG, and a subject specified music therapy method.     

一种基于DSP的信号分选硬件平台设计

在高密集复杂雷达信号环境下,雷达信号分选实时性是信号处理的一项关键技术,也是电子战领域一个有待提高的关键课题。利用高性能数字信号处理器（DSP）和现场可编程门阵列构建了一种双DSP信号分选硬件平台,极大地减少了分选的时间开销和分机系统的体积。实验结果表明,此方法极大地提高了信号分选的实时性。