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跨通道冲突加工中认知控制的调控机制
Alternative TitleThe Regulation Mechanisms of Cognitive Control during Multisensory Conflict Processing
李政汉
2020-10
Abstract

认知控制(cognitive control )是指在特定的情境中,个体为了达到具体的目的和意图,灵活地、自适应地调动注意资源来动态地调整想法和行动的心理过程。作为一种核心的高级认知功能,认知控制参与从感知觉、注意、学习和记忆到情绪调节、奖励决策等心理过程的方方面面,在人类智能中起关键作用。在实验室,研究者们开发了很多经典的冲突任务范式来研究认知控制的作用机制,使用最为广泛的当属刺激 反应协同性任务,比如经典的 Stroop 范式、 Simon 范式和 Flanker范式。一般认为冲突加工中,认知控制调节注意分配的作用机制有两种:一种是对任务相关刺激的加工增强( enhancement ),另一种是对任务无关刺激的加工抑制( inhibition ),而相关理论模型大多将两者有机结合,认为是两种过程共同作用的结果。但近期的一些实证研究又发现了很多不一致的结果,重新引发了关于认知控制调控机制的争议。探明认知控制是通过相关刺激的加工增强还是无关刺激的加工抑制来调节注意,不仅可以探究注意资源是如何分配的,也有助于加深人们对认知控制网络与其他脑网络之间作用关系的理解,既能完善相关理论,也可以推广应用于有认知控制障碍的群体来提升他们的认知控制能力。本文基于以往的研究开发了系列的Stroop范式,利用脑电、功能磁共振和脑磁技术手段,试图从时空角度来探究认知控制的调控机制。本文共包括四个研究(6个实验),详述如下。

研究一(实验1 、 2 ):该部分 采用了脑电技术, 设计了两个单通道的性别加工 Stroop 任务,分别是视觉注意任务和听觉注意任务。视觉注意任务中,被试需要判断屏幕中出现的面孔性别忽略面孔上汉字的影响;听觉注意任务中,被试需要判断听到的声音是男声还是女声,忽略声音内容的影响。我们分别在视听Stroop 任务中发现了认知控制的调控机制。此外,结合视觉注意任务中的 P3 、conflict SP 成分和听觉注意任务中的 Ninc 成分,我们得出结论:较为早期(刺激出现 300 ms 之内)的脑电信号可以区分是否出现任务无关刺激但无法识别干扰信息的语义,而较为晚期( 300 ms 之后)的脑电信号可以区分是否出现任务无关刺激且能识别干扰信息的语义。

研究二(实验3 ):该部分基于我们实验室开发的视听跨通道 Stroop 范式采集了24名被试的脑电数据,来探寻认知控制调控机制的神经学证据。实验1中的目标刺激始终是屏幕中的箭头,被试需要判断箭头的朝向,干扰刺激可能来自于视觉通道(听觉刺激为中性)或听觉通道(视觉刺激为中性)。任务相关刺激始终来自于视觉通道,任务无关信息则可能会出现变化(即视觉或听觉通道),而我们发现当前后试次的任务无关刺激通道发生变化时,P3成分和theta、alpha及beta1频段的冲突适应效应消失,说明这些可能是认知控制调节作用的神经指标,而且表明认知控制的调节作用一定涉及任务无关刺激的加工抑制。

研究三(实验4):基于研究二,我们结合视听注意任务开发了跨通道的性别Stroop任务,利用具有高空间分辨率的磁共振技术把任务相关刺激和任务无关刺激的加工分离到相应的特异性脑区。实验4一共包含三个任务,分别是视觉注意任务、听觉注意任务和匹配任务。我们采用了全脑分析和感兴趣区分析,发现相比于匹配任务,在完成视觉注意任务时,视觉区和面孔特异性加工脑区的激活都显著增强,表明任务相关刺激加工被增强了。此外,我们分别对视觉区和听觉区进行了模式相似性分析,结果发现相比于匹配任务,在完成视觉注意任务时,视觉区的模式相似性显著更高,而在完成听觉注意任务时,视觉区的模式相似性显著更低。表明任务相关刺激加工脑区的相似性被增强,而任务无关刺激加工脑区的相似性被抑制。相关分析发现视觉注意任务中视觉区的激活增强与两侧顶内沟有关,而听觉注意任务中视觉区激活的减弱与前扣带回与背外侧前额叶有关。

研究四(实验5 、 6 ):研究四 采用了脑磁技术,首先 优化了实验 4 的设计,减少了匹配任务,只包含了视觉注意任务和听觉注意任务两个,但增加了中性条件。被试在看到一个字母的同时会通过耳机听到一个字母,在视觉注意任务中,被试需要判断看到的字母是什么而忽略听到的字母;在听觉注意任务中,被试需要判断听到的字母是什么而忽略看到的字母。在视觉注意任务的中性条件下,听到的声音为粉噪音;在听觉注意任务的中性条件下,看到的字母则为一个黑色的色块。在行为层面,我们发现相比于中性试次 ,冲突试次的反应时更大,错误率更高,在神经层面,我们发现视觉注意任务中,枕叶区 alpha 波段的活动在刺激出现后开始减弱,且相比于中性条件,冲突条件下枕叶区 alpha 波段活动减弱的强度更高,表明了任务相关刺激(视觉信息)的加工增强;在听觉注意任务中,枕叶区 alpha 波段的活动在 Stroop 任务呈现之后开始增强,且相比于中性试次,冲突试次枕叶区alpha波段的活动增强更多,表明了任务无关刺激(视觉信息)的加工抑制,且抑制水平在刺激出现后100-300ms达到顶峰。此外,我们发现alpha波段的功率与反应时呈显著的负相关,我们推测alpha波段的活动对任务无关刺激的抑制促进了冲突解决。

上述四个研究从时间和空间的视角出发,研究一分别探究了认知控制在视觉和听觉通道冲突加工中的神经机制,为后续的跨通道研究做了铺垫;研究二通过操纵任务无关刺激的通道变化,发现了任务无关刺激的加工抑制;研究三利用脑成像技术找到了支持任务相关刺激加工增强和任务无关刺激加工抑制同时存在的直接证据;研究四则借助脑磁技术高时空分辨率的优势,结合时间和空间两个角度探究了认知控制调控机制的动态变化。综上,我们发现任务相关刺激的加工增强更多是在冲突加工的早期,发生在初级感觉皮层,任务无关刺激的加工抑制发生的时间稍晚,而视听跨通道冲突加工过程中,认知控制似乎更多通过调节视觉信息的加工促进冲突解决。

Other Abstract

Cognitive control refers to the process of allocating attention resources flexibly and adaptively in response to context-specific goals and intentions. Cognitive control plays an essential role in human cognitive processes, including sensory perception, attention, emotion regulation and decision making. In the laboratory, researchers have developed many classic conflict tasks to study the mechanism of cognitive control. The most widely used task arestimulus-response compatibility (SRC) tasks, such as the Stroop task, Simon task and Flanker task. It is generally believed that in conflict processing, there are two mechanisms for cognitive control to regulate attention allocation. One is the enhancement of task-related stimuli, and the other is the inhibition of task-irrelated stimuli. Most of the relevantmodels tend to integrate these two processes, proposing that the regulation of cognition control is the result of the joint effect of the two processes. However, some recent empirical studies have found many inconsistent results, which have reignited the controversy about mechanismsof cognitive control regulation. Exploring the regulation mechanisms of cognitive control can not only figure out how attention resources are allocated, but also help to deepentheunderstanding of the relationship between cognitive control network and other neural networks. Meanwhile,the understanding of regulation mechanisms can not only contribute to related theories, but also could help to improve the cognitive control abilities for the groups with cognitive control disorders. We developed a series of Stroop paradigms based on previous studies, and used EEG, fMRI and MEG to explore the regulation mechanism of cognitive control from a spatio-temporal perspective. This dissertation includes four studies (six experiments), which are described as detailed below.

Study 1 (Experiments 1 and 2): In this part, two unimodal gender-Stroop tasks wereutilizedto collect EEG data, i.e., visual attention task and auditory attention task. In the visual task, the participantswere instructed to judge the gender of the face that appears on the screen and ignore the influence of the Chinese characters on the face.In the auditory attention task, the participantswere asked to judge whether the voice they

heard was male or female while ignoring the influence of the sound content. We found the modulation of cognitive control in both visual and auditory Stroop tasks. Furthermore, combining the patterns of P3 and conflict SP components in the visual attention task and the Ninccomponent in the auditory attention task, we concludedthat the earlier ERP signals (within 300 ms of the stimulus) can distinguish whether there is a task-irrelevant stimulus but cannot recognize the meaning of interference information, whilethe advancedERP signals (after 300 ms) can not only identify whether there are task-independent stimuli but also can recognize the meaning of interference information.

Study 2 (Experiment 3): Based on the audiovisual Stroop paradigm developed byour laboratory, we collected the EEG data of 24 subjects to explore the neurological indices of cognitive control regulationmechanism. The target in Experiment 1 is always the arrow on the screen. Participants were asked to judge the direction of the arrow. The interference stimulus may come from the visual modality (in which the auditory stimulus was neutral) or auditory modality (in which the visual stimulus was neutral). Task-relevant stimuli always camefrom the visual modality, and task-relevantinformation may come from different modalities (visual or auditory modalities), and we found that when the modality of task-irrelevant stimulus alternated, the conflict adaptation (CA) effects on the P3 amplitude and theta, alpha and beta1 bands power disappeared. The disappearance of the CA effect provided theneural evidence that the regulation of cognitive control must involve the processing inhibition of task-irrelevant stimuli.

Study 3 (Experiment 4): Based on Study 2, we combined the visual and auditory attention tasks to develop a cross-modal gender Stroop task and took advantage of the high spatial resolution of fMRI to separate the processing of task-relevant stimuli and task-irrelevant stimuli into corresponding specificbrain areas.The results showedthat during conflict processing, both the enhancement of task-relevant and the inhibition of task-irrelevant stimuli existed. In addition, we also found that the enhanced representation of the visual area in the visual attention task was correlated with the activation of left IPS and right IPS, while theinhibition of the visual area representation during the auditory attention task was correlated with the deactivation of ACC and left DLPFC.

Study 4 (Experiments 5 and 6): Utilizing theMEG technology,wesimplifiedand optimizedthe design of Experiment 4 by excluding the matching tasks and adding neutral conditions. Participants wouldhear a letter through earphones when they sawa letter on the screen. In Experiment 5 (visual attention task), the participants were askedto judge the letter they saw and ignore the letter they heard. InExperiment 6 (auditory attention task), the participants were asked to judge theletters they heard and ignore the letters they saw. In the neutral condition of the visual attention task, the auditory stimulus was pink noise while in the neutral condition of the auditory attention task, the visual stimulus was a black square. The increasing of Alpha-bands activity in the occipital area indicated the enhancement of target-relevant stimulus processing in the visual task while the increasing of Alpha-bands activity in the occipital area indicated the inhibition of target-irrelevant stimulus processing in the auditory task.

With the above four studies we explored the regulation mechanisms of cognitive control with a series of Stroop tasks from the spatio-temporal perspective.Study1 explored the control mechanisms of cognitive control during visual and auditory conflict processing. In Study 2, we manipulated the alternation of distractor and revealed the inhibition of task-irrelevant stimuli during the regulation of cognitive control. Utilizing fMRI technology, study 3 providedthedirect evidence for the simultaneous existence of task-relevant stimulus processing enhancement and task-irrelevant stimulus processing inhibition. Study 4 took advantages of high spatiotemporal resolution of magnetoencephalogram to explore the dynamics of cognitive control regulation mechanisms from both temporal and spatial perspectives. The results showed that the enhancement of task-relevant stimuli occurred mainly in the early stage of conflict processing and in the primary sensory cortex, and the inhibition of task-independent stimuli was relative late.

Keyword冲突加工 认知控制 任务相关刺激加工增强 任务无关刺激加工抑制 时间空间
Subtype博士
Language中文
Degree Name理学博士
Degree Discipline认知神经科学
Degree Grantor中国科学院心理研究所
Place of Conferral中国科学院心理研究所
Document Type学位论文
Identifierhttp://ir.psych.ac.cn/handle/311026/33943
Collection认知与发展心理学研究室
Recommended Citation
GB/T 7714
李政汉. 跨通道冲突加工中认知控制的调控机制[D]. 中国科学院心理研究所. 中国科学院心理研究所,2020.
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