基于结构MRI的运动想象BCI机制研究

发布时间：2018-07-08 16:18

本文选题：脑机接口 + 运动想象　；参考：《电子科技大学》2014年硕士论文

【摘要】：脑机接口系统是指不依赖于大脑的信息传出通路,通过脑电放大器等一系列设备直接完成人与外接设备的通信的系统。脑机接口涉及到许多学科,如信号采集、特征分类、模式识别等。其中基于运动想象的脑机接口系统,由于其和运动功能中枢紧密关联,在运动功能康复等领域具有潜在的应用价值,因此受到了广泛的关注。但是人群中约有20%左右的盲被试,即在现有的刺激范式下不能有效诱发分类所需要的节律特征信号,而且也不能通过增加训练的重复次数来提高在线系统的表现正确率。本文主要对这类盲被试与正常被试进行组间比较,从而挖掘其在脑结构特征与大脑纤维束连接方面的区别,从而很好地识别人群中的盲被试,并为运动想象脑机接口研究提供必要的神经机制理论基础。本论文的工作主要如下:1.被试筛选和数据获取。由于研究对象需要获得较为可靠的盲被试。本论文设计了相应的运动想象实验范式,通过多次的在线和离线实验,获取相应的脑电数据,基于脑电数据对被试的BCI能力进行评估,并完成对被试的筛选。筛选出的被试进行了结构磁共振,静息功能磁共振数据的获取,本论文主要基于结构磁共振进行了相应机制的研究。2.通过对两组被试的结构的皮层厚度、灰质体积、表面积等指标的分析,我们发现,正常BCI表现好被试左脑的内侧枕颞腹侧沟的皮层厚度、灰质体积、表面积等参数比表现较差被试体现出较大的值(p0.05);同样在在中央前回脑区的表面积和定点个数方面,表现较差的被试比正常被试的值要小,这揭示了结构上的差异对两组被试间的表现差异的影响。同时相关结构指标和BCI表现的关联分析表明,脑区的皮层表面积和灰质体积指标和BCI表现有密切的关联。3.基于DTI结构的分析结果发现,中央前回、额下回、额上回、中央沟盖等脑区的纤维束连接与被试在线系统的表现呈现高度相关(r0.5,p0.05),可望为脑机接口在线表现和被试筛选提供相应的生理指标。除了额顶网络,纤维束连接研究也显示了尾状核、楔前叶等边缘系统对运动想象能力的影响作用。同时两组间的对比分析结果揭示了,在扣带回、海马等结构上,两组被试间存在显著性的差异。
[Abstract]:Brain-computer interface system (BCI) is a system that can directly communicate between human beings and external devices through a series of devices, such as EEG amplifiers, which do not depend on the information efferent pathway of the brain. BCI involves many subjects, such as signal acquisition, feature classification, pattern recognition and so on. The brain-computer interface system, which is based on motion imagination, has been paid more and more attention because of its close relationship with motor function center and its potential application value in the field of motor function rehabilitation and so on. However, about 20% of the blind subjects in the population can not effectively induce the rhythmic characteristic signals needed for classification under the existing stimulus paradigm, and can not improve the performance accuracy of the online system by increasing the number of training repeats. In this paper, we compared this kind of blind subjects with the normal subjects in order to dig out the differences between the brain structure characteristics and the connections of the cerebral fiber bundles, so as to identify the blind subjects in the population. It also provides the necessary theoretical basis of neural mechanism for the study of brain-computer interface in motor imagination. The work of this thesis is as follows: 1. The subjects were screened and the data were obtained. Because the subjects need to obtain more reliable blind subjects. In this paper, we design the corresponding experimental paradigm of motion imagination, obtain the corresponding EEG data through many online and offline experiments, evaluate the BCI ability of the subjects based on the EEG data, and complete the screening of the subjects. The structural magnetic resonance (SRM) and resting functional magnetic resonance (fMRI) data were obtained from the selected subjects. By analyzing the cortical thickness, gray matter volume and surface area of the structure of the two groups, we found that the normal BCI showed good cortical thickness and gray matter volume in the medial occipito-temporal sulcus of the left brain of the subjects. The surface area and other parameters were larger than those of the poor subjects (p0.05), and the values of the surface area and the number of fixed points in the precentral gyrus were smaller than those of the normal subjects. This reveals the effect of structural differences on the performance differences between the two groups. The cortical surface area and gray matter volume index were closely related to BCI performance. The results of DTI-based analysis showed that precentral gyrus, inferior frontal gyrus, suprafrontal gyrus, There is a high correlation between the fiber bundle connection and the performance of the online system in the central sulcus and other brain regions (r0.5 / p0.05), which is expected to provide the corresponding physiological index for the on-line performance of the brain-computer interface and the screening of the subjects. In addition to frontal-parietal networks, the effect of edge systems such as caudate nucleus and anterior wedge on motor imagination is also demonstrated. At the same time, the results of comparative analysis between the two groups revealed that there were significant differences in the structures of cingulate gyrus and hippocampus between the two groups.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R445.2;TN911.7

【共引文献】