稳态视觉诱发响应的检测技术与应用

发布时间：2018-04-30 03:37

本文选题：视觉系统 + 稳态视觉诱发电位　；参考：《电子科技大学》2010年硕士论文

【摘要】： 当用一个强度和频率恒定的视觉刺激作用于人眼时,在人脑的视觉皮层区会产生一个和视觉刺激频率或其谐波频率相关的响应,即稳态视觉诱发响应(steady-state visual evoked responses,SSVER),其相应的大脑皮层电位称为稳态视觉诱发电位(steady-state visual evoked potentials,SSVEP)。由于SSVEP具有强的抗干扰特性,因此被广泛应用于视觉神经机制的相关研究中。然而,限于目前各类神经电活动检测技术(如EEG/MEG/fMRI)在时空分辨率上的不兼容性,制约了SSVEP在相关领域上的研究进展。本文将就SSVEP在视觉神经机制上的应用以及SSVEP的可能的新检测技术展开探讨,内容主要包括: 1.通过使用具有固定强度不同频率的闪光对被试进行单眼和双眼刺激,采集头皮EEG数据,对不同刺激条件下产生的SSVEP的幅度和相位进行研究。结果发现,随着刺激频率升高,产生的SSVEP信号呈现出不稳定趋势;无论是单眼还是双眼接受频闪刺激,左右枕叶的活动强度具有对称性且相位同步,说明左右枕叶功能同步是视觉信息处理的第一步;当双眼分别注视相似物体时,将会形成单一、稳定的视知觉,这是因为视皮层通过功能同步对左右眼接受的相似视觉信息进行了整合,且这个整合过程并不需要高级的视觉加工。 2.基于目前已有的脑功能检测技术本身的局限性,我们提出使用具有高时空分辨率且可直接检测神经电活动的神经电流磁共振(neuronal current MRI, nc-MRI)检测方法,并从计算机理论仿真及实验两方面入手,对nc-MRI的可行性进行探讨。理论仿真的结果表明,相向树突分支的存在可以提高神经磁场的可检测性,一方面,单个活动体素的nc-MRI幅度信号仍然足够大,可以应用MRI直接检测;另一方面,nc-MRI的相位信号有所提高,但具不稳定性。因此,我们建议在采用nc-MRI进行神经电活动的检测时,最好采用幅度信号作为nc-MRI的检测参数。但是,在我们应用nc-MRI进行神经电活动检测的的应用研究中,并没有检测到任何的与SSVEP或α波样活动相关的信号。我们认为主要的原因是在真实环境下,神经活动产生的神经电磁场相对于其他的一些生理信号如BOLD(blood oxygen level dependent)等所产生的磁场较小,被淹没在这些背景磁场噪声中。
[Abstract]:When a visual stimulus of constant intensity and frequency is applied to the human eye, a response related to the frequency of the visual stimulus or its harmonic frequency is produced in the visual cortex of the human brain. The steady-state visual evoked response is called steady-state visual evoked potential. The corresponding cerebral cortex potential is called steady-state visual evoked potentials. SSVEP is widely used in the study of visual neural mechanism because of its strong anti-interference characteristics. However, due to the incompatibility of the spatiotemporal resolution of all kinds of neural electrical activity detection techniques (such as EGR / MEG / f MRI), the research progress of SSVEP in related fields is restricted. This paper will discuss the application of SSVEP in visual neural mechanism and the possible new detection technology of SSVEP. The main contents are as follows: 1. The amplitude and phase of SSVEP produced under different stimulation conditions were studied by collecting scalp EEG data by using flash with fixed intensity and different frequency to stimulate monocular and binocular. The results showed that with the increase of stimulation frequency, the SSVEP signal produced showed an unstable trend, and the activity intensity of the occipital lobe was symmetrical and the phase was synchronous, whether it was a single eye or a binocular stroboscopic stimulus. It shows that the synchronization of the left and right occipital lobes is the first step in visual information processing. When the eyes respectively look at similar objects, they will form a single, stable visual perception. This is because the visual cortex integrates similar visual information received by the left and right eyes through functional synchronization, and this integration process does not require advanced visual processing. 2. In view of the limitations of the existing brain function detection techniques, we propose a neural current magnetic resonance current MRI (nc-MRI) method with high spatial and temporal resolution, which can directly detect neuronal current activity. The feasibility of nc-MRI is discussed from two aspects of computer simulation and experiment. The theoretical simulation results show that the existence of phase dendritic branches can improve the detectability of neural magnetic field. On the one hand, the nc-MRI amplitude signal of a single active element is still large enough to be directly detected by MRI. On the other hand, the phase signal of nc-MRI is increased, but unstable. Therefore, we suggest that the amplitude signal should be used as the detection parameter of nc-MRI when nc-MRI is used to detect the neuroelectric activity. However, no signals related to SSVEP or 伪 -wave activity were detected in our application of nc-MRI for neuroelectric activity detection. We think that the main reason is that in real environment, the neural electromagnetic field produced by neural activity is smaller than that produced by other physiological signals such as BOLD(blood oxygen level dependent), and is submerged in the noise of these background magnetic fields.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：R77

【相似文献】