健康与遗传心理学研究室知识库

    声调研究是近几年汉字认知研究的热点。本文将首先介绍汉字特别是声调的特点及其相关的行为学研究，然后从声调的耳优势、脑损伤病人的声调加工及声调的功能成像研究二个方面重点介绍声调的脑偏侧化研究。这些研究对声调加工理论进行了检验。接着在上述综述的基础上提出本文的研究问题及方法:
    研究问题—运用行为学研究中的反应时记录法及功能磁共振成像技术进一步研究汉字声调的行为特征及脑激活模式。
    研究方法—33名被试执行汉字出声阅读任务，反应记录反应时。根据形声字声旁与整字间读音及声调相同与否，将刺激材料细分为4类，分别为同音同调字、同音异调字、异音同调字和异音异调字，每类20字。刺激用视觉方式随机呈现。13名被试在磁共振扫描过程中执行与上述行为学研究相同的任务。
    行为学研究结果显示读音的主效应显著而声调的主效应不显著，两者的交互作用边缘显著。功能磁共振成像研究显示四种条件均激活双侧额中回、额下回、双侧颗上回、双侧岛叶、前运动区、辅助运动区，以及左侧梭状回和右侧小脑，另外，不同类型刺激也有不同的激活，譬如内侧颗n-卜和额中回。四种条件的脑偏侧化程度不尽相同。另外，本实验还观察到这四种条件在右侧颖上回、双侧额下回等区域激活模式的特征性变化。
    综合上述结果，本研究得到以下结论:
    1本实验条件下，声调的行为学效应不显著，而脑成像技术能够有效分离声调代  表的超音段信息与读音代表的音段信息。
    2各脑区对声调与读音的加工有重叠又有分离，这说明声调加工是一个很复杂的过程，该研究提供了初步的声调加工的脑基础。
    3声调加工偏侧化休现在左右脑的不同区域，功能假设和声学假设并不对立。
    4在汉字规则性效应研究中，声调的作用不应忽略。

    Tone is the subject of intensive study in the field of cognitive research on Chinese characters in recent years. This thesis first describes characteristics of Chinese characters especially oftone and related behavioral studies, and then reviews recent studies on tonal ear advantage, tonal process of brain damaged patients, and tonal research with functional magnetic resonance imaging(fMRI), which tested tonal process theories. On the basis of this review, we conducted the following study.
    Object: to investigate behavioral characteristics and activation of Chinese character tone processing,  by use of behavioral test and functional magnetic resonance imaging.
Methods: 30 participants were asked to name visually presented Chinese characters and reaction time for each stimulus was recorded. According to the consistency of the pronunciation and tone between phonetic radicals and whole characters, the stimulation materials were grouped into four types:  pronunciation-same-tone-same character,pronunciation-same-tone-difference character, pronunciation-difference-tone-same character and pronunciation-difference-tone-difference character. There were 20 characters for each stimulus type. Another 13 participants were scanned with a 1.5 T MRI scanner while performing the same tasks.
    The behavioral study showed that the main effect of pronunciation was significant while that of tone was not. The fMRI experiment indicated that all four types of stimuli activated  bilateral  middle  frontal gyrus,  inferior  frontal  gyrus, premotor cortex supplementary motor area, superior temperal gyrus and left fusiform. A few regions, such as medial frontal gyrus and middle temperal gyrus, were activated in only some types of stimuli. There were differences in brain lateralization across four different conditions.This experiment also characterized the activation patterns, i.e., time course of activation,in right superior temperal gyrus. bilateral inferior frontal gyrus, and other regions.
    Based on the above results, we conclude:
    1.Comparing to traditional studies usually with auditory modality, visual modality provides a novel approach to understand tonal processing.
    2.The finding of semi-regularity effect in Chinese characters processing associated with   tone processing suggests that the impact of tone on process should take into account.
    3.Tone effect cannot be effectively identified by reaction time, but can be recorded by fMRI used in the present study.
    4.There is hemispheric laterality in the process of Chinese characters, including tone processing.