听觉想象的大脑表征

PSYCH OpenIR > 中国科学院心理研究所回溯数据库(1956-2010)

	听觉想象的大脑表征
其他题名	Cortical Representation of Auditory Imagery
	吴健辉
	2008-05-27
摘要	想象是一种内部表征。本研究就其大脑机制的两方面进行探讨：时间进程和这种表征的本质。关于想象的本质，存在着命题论和描绘论之争：想象只是抽象的语义表征，还是类似于知觉的“图画”。以往的行为研究表明，想象表征了外在世界的物理信息，如空间、大小；脑成像和神经心理学研究发现，感觉皮层、尤其是初级感觉皮层参与了想象；在视觉通道的研究进一步表明，想象时初级视觉皮层的激活模式反映了所想象物体的大小和方位信息，从而有力的支持了描绘论。在听觉通道，尽管行为研究证明听觉想象和听觉知觉一样，包含了音高、音响信息，但缺乏神经科学证据。本研究采用事件相关电位技术，通过“提示－想象（刺激1）－刺激2”范式，研究听觉想象脑机制的时间进程，并且多角度的证明听觉想象的大脑表征包含了音高和音响信息。研究结果发现：第一、根据提示进行听觉想象时，想象效应开始于P2波幅的增强，可能反映了想象任务导致的自上而下的注意资源分配；接着是晚正成分（late positive component, LPC），可能反映了听觉想象的形成。第二、LPC波幅与所想象声音的音高成反比，与音响成正比，这样的变化趋势与听觉知觉成分N1是一致的，从而证明听觉想象的脑机制表征了音高和音响信息。第三、在刺激2呈现的比较阶段，当呈现的声音（刺激2）与先前想象的声音（刺激1）具有不一致的音高或音响时，会导致反应时的延长，和诱发冲突性的N2成分；而且随着不一致程度的增大，反应时缩短和N2波幅增大。这进一步证明听觉想象包含了音高和音响信息。本研究首次提出，想象起始于注意资源的分配过程；并且首次证实，在随后的想象形成阶段，听觉想象的大脑表征包含了声音的物理信息，为描绘论提供了来自于听觉通道的神经科学证据。
其他摘要	As a species of internal representation, how is mental imagery organized in the brain? There are two issues related to this question: the time course and the nature of mental imagery. On the nature of mental imagery, today's imagery debate is influenced by two opposing theories: (1) Pylyshyn’s propositional theory and (2) Kosslyn’s depictive representation theory. Behavioural studies indicated that imagery encodes properties of the physical world, such as the spacial and size information of the visual world. Neuroimaging and neuropsychological data indicated that sensory cortex; especially the primary sensory cortex, is involved in imagery. In visual modality, neuroimaging data further indicated that during visual imagery, spatial information is mapped in the primary visual, providing strong evidences for depictive theory. In the auditory modality, behavioural studies also indicated that auditory imagery represents loudness and pitch of sound; this kind of neuroimaging evidence, however, is absent. The aim of the present study was to investigate the time course of auditory imagery processing, and to provide the neuroimaging evidence that imaginal auditory representations encode loudness and pitch information, using the ERP method and a cue-imagery (S1)-S2 paradigm. The results revealed that imagery effects started with an enhancement of the P2, probably indexing the top-down allocation of attention to the imagery task; and continued into a more positive-going late positive potentials (LPC), probably reflecting the formation of auditory imagery. The amplitude of this LPC was inversely related to the pitch of the imagined sound, but directly related to the loudness of the imagined sound, which were consistent with auditory perception related N1 component, providing evidences that auditory imagery encodes pitch and loudness information. When the S2 showed difference in pitch of loudness from the previously imagined S1, the behavioral performance were significantly worse and accordingly a conflict related N2 was elicited; and the high conflict elicited greater N2 amplitude than low conflict condition, providing further evidences that imagery is analog of perception and can encode pitch and loudness information. The present study suggests that imagery starts with an mechanism of top-down allocation of attention to the imagery task; and continuing into the step of imagery formation during which the physical features of the imagined stimulus can be encoded, providing supports to Kosslyn’s depictive representation theory.
关键词	事件相关电位(ERP) 听觉想象晚正成分(LPC) 描绘论
学位类型	博士
语种	中文
学位授予单位	中国科学院心理研究所
学位授予地点	心理研究所
文献类型	学位论文
条目标识符	http://ir.psych.ac.cn/handle/311026/4652
专题	中国科学院心理研究所回溯数据库(1956-2010)
推荐引用方式 GB/T 7714	吴健辉. 听觉想象的大脑表征[D]. 心理研究所. 中国科学院心理研究所,2008.

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