视听相互作用的源定位及皮层网络分析

发布时间：2018-06-23 15:17

  本文选题：视听交互 + 变化判断　； 参考：《上海交通大学》2012年硕士论文

【摘要】：日常生活中，人们常常需要整合来自不同感觉器官的信息来认识外部世界。作为人类非常重要的两个感觉通道，视觉和听觉之间的相互作用一直备受关注。在视听交互的过程中，一致的视听刺激能够促进认知而不一致的视听刺激则可能会干扰认知。虽然对视听一致性的研究已经取得了很多成果，但是对于视听刺激的变化的感知至今却少有研究，而视听刺激变化的一致性问题以及该情况下大脑活动的源和皮层神经网络的研究就更加缺乏了。因此，本文旨在研究视觉影响下受试者对听觉响度的变化进行判断的过程，以帮助我们更好地理解人类的心理认知过程和视听交互作用的神经机制。 在实验中，我们让12名受试者判断先后呈递的两个听觉刺激在响度上是否发生变化，同时可能伴随或者不伴随两个同步的视觉刺激（圆盘的大小可能相同或者不同）。行为学和脑电信号都被采集以进行分析。 为了寻找头皮脑电对应的颅内源，从而定位认知活动涉及的脑区，神经领域的学者们采用了许多方法，其中偶极子定位法（DipoleLocalization Method, DLM）是进行脑电溯源分析的一种常用方法。而在描述大脑皮层间的相互作用时，相较于以往的互相关、互信息等方法，部分直接相干（Partial Directed Coherence, PDC）法更好地体现了皮层区域之间作用的强度和方向，并且这种因果性的联系体现的是通道间的直接相关性。基于脑电信号的高时间分辨率，本文通过DLM和PDC研究视听交互不同阶段大脑的激活情况以及在变化的视觉影响下对听觉响度进行变化判断的皮层相互作用网络，以了解这一认知过程中大脑活动的时空特性。 行为学的结果显示，不论视觉还是听觉刺激存在信息变化时，受试者更易受到视听一致性的影响。通过对采集到的头皮脑电信号做事件相关电位（Event-related Potential, ERP）差异波和统计检验，可以发现视听交互作用最显著的两个时间窗，即160-200ms和300-400ms，然后进行溯源分析和皮层网络分析。（1）利用DLM分别在160-200ms和300-400ms时间窗进行溯源分析，发现（i）第一个时间窗内有两个偶极子，，分别是脑岛（BA13）和压后皮层乏颗粒区（BA30），它们可能分别参与第一个视听刺激的交互作用以及相应的工作记忆；（ii）第二个时间窗内也有两个偶极子，前运动区皮质（BA6）可能主要参与了决策的做出和声音响度的区分，而尾状核可能是与第二个刺激的视听交互作用以及前后两个声音区分任务中的工作记忆相关。（2）PDC的分析考虑到上述时间窗以及建模的稳定性，选择49-198ms和271-420ms两个时间窗口进行，基本将溯源分析的两个窗口包括在内。发现（i）在第一个窗口中，半球内部与半球间的联系强度近似。视听刺激相较于单一模态的刺激，左半球内及半球间（尤其是左半球向右半球）联系增强。对于视听刺激来说，除了有左侧颞叶和双侧枕叶加入到刺激处理过程中，额叶与枕叶以及中央顶区与枕叶的有向连接可能反应了视听刺激的交互作用。（ii）到了第二个窗口，视听刺激相较于单一模态的刺激，左半球向右半球的联系大大增强且右半球内交互作用增强。与单一模态相比，视听网络中两侧额叶发挥着重要的作用，且双侧顶叶和额叶之间的联系（P3-F4, P4-F3）增强。 本文的初步结果表明，在视听刺激变化判断任务中，随着时间的推移，大脑活动的颅内源发生变化，皮层网络显示大脑右侧半球占据了主导地位，并且额叶和顶叶在高级认知活动（即决策和区分）中发挥了重要的作用。这不仅将视听一致性的研究扩展到了变化感知上，还进一步阐述了交互过程中的时空动态特性以及因果性的皮层相互作用，揭示了视听交互作用的内在神经机制。
[Abstract]:In everyday life, people often need to integrate information from different sensory organs to understand the external world. As two very important sensory pathways of human beings, the interaction between vision and hearing has been concerned. In the process of audio-visual interaction, consistent audio-visual stimuli can promote cognitive and inconsistent audio-visual stimuli. Although many achievements have been made in the study of audio-visual consistency, there is little research on the perception of audio-visual stimuli, and the consistency of the audio-visual stimuli and the research on the source of brain activity and the cortical neural network in this case are more lacking. Therefore, this paper aims to study visual shadow. The process of judging the changes in the auditory loudness is made to help us to better understand the cognitive processes of human beings and the neural mechanisms of audiovisual interaction.
In the experiment, 12 subjects were asked to determine whether the two auditory stimuli that were successively presented changes in the loudness, and may be accompanied by or not accompanied by two synchronous visual stimuli (the size of the disc may be the same or different).
In order to find the intracerebral sources corresponding to the scalp electroencephalogram (EEG) and to locate the brain areas involved in cognitive activity, the scholars in the field of Neurology have adopted many methods, in which DipoleLocalization Method (DLM) is a common method for the analysis of EEG traceability. Intercorrelation, mutual information and other methods, the partial direct coherence (Partial Directed Coherence, PDC) method better reflects the intensity and direction of the function between the cortical regions, and this causal link reflects the direct correlation between channels. Based on the high time resolution of EEG signals, this paper studies the different visual and audiovisual interaction through DLM and PDC. In order to understand the temporal and spatial characteristics of brain activity in this cognitive process, the activation of the brain and the changes in the visual influence of the auditory loudness are determined by the changes of the brain.
The results of behavioral studies show that subjects are more susceptible to audiovisual congruence, regardless of visual or auditory stimuli. By using the Event-related Potential (ERP) difference wave and statistical test of the collected scalp brain electrical signals, the most significant two time windows of audio-visual interaction can be found. 160-200ms and 300-400ms, followed by traceability analysis and cortical network analysis. (1) traceability analysis by DLM in 160-200ms and 300-400ms time windows, and found that there are two dipoles in the first time window, namely, the insula (BA13) and the posterior cortex (BA30), which may be involved in the interaction of the first audio-visual stimuli respectively. Using and corresponding working memory; (II) there are also two dipoles in the second time windows, and the anterior motor cortex (BA6) may be mainly involved in the decision making and sound loudness, and the caudate nucleus may be related to the audio-visual interaction of second stimuli and the working memory of the two sound discrimination tasks. (2) the PDC score. In view of the above window and the stability of the modeling, the two windows of 49-198ms and 271-420ms are selected and the two windows of the traceability analysis are included. It is found that (I) in the first window, the intensity of the relationship between the hemispheres and the hemispheres is similar. In addition to the left temporal and bilateral occipital lobes added to the stimulus treatment, the frontal and occipital lobes, as well as the central apex and occipital lobes, may respond to audio-visual stimuli in audio-visual stimuli. (II) to second windows, audio-visual stimuli are compared to a single mode. The relationship between the left hemisphere and the right hemisphere is greatly enhanced and the interaction between the right hemisphere is enhanced. Compared with the single mode, the frontal lobes in the audio-visual network play an important role, and the relationship between the bilateral parietal lobe and the frontal lobe (P3-F4, P4-F3) is enhanced.
The preliminary results of this paper show that the brain activity changes in the brain as time goes on, and the cortical network shows the dominant position of the right hemisphere in the brain, and the frontal and parietal lobes play an important role in the advanced cognitive activity (that is, decision making and differentiation). The research extends to the change perception, and further expounds the temporal and spatial dynamic characteristics and the causal cortical interaction in the interaction process, and reveals the intrinsic neural mechanism of the audio-visual interaction.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.0

【参考文献】

中国硕士学位论文全文数据库 前1条

1 葛小立;视听一致性对声音响度变化判断的影响[D];上海交通大学;2011年

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