Developmental change of hemispheric dominance using visual event-related potentials (ERPs)

为了确定视觉识别的优势半球，研究大脑半球优势的发育变化，对20名正常青春期(21~45岁)和40名正常儿童(6~12岁)进行了事件相关电位(ERPs)检测。采用速测仪和“古怪”范式分别呈现言语刺激(“假名”)和非言语刺激(“点”在空间和“面”)的视觉刺激，正常青少年(右利手)言语刺激右侧视野的P300波幅高于左侧视野。非语言刺激左视野的P300波幅高于右视野的P300波幅。这些发现提示，对速视视觉刺激的P300可以决定大脑半球的优势。在正常右利手儿童中，言语认知优势半球出现在左侧，非言语认知优势半球出现在右侧。6岁以上正常右利手儿童言语刺激右侧视野的P300波幅也高于左侧视野。8岁以上儿童非言语刺激“点”刺激左视野的P300波幅高于右视野。这些结果表明，在6岁以上的儿童中，言语认知的半球优势已经出现在左侧，在8岁以上的儿童中，非言语认知的半球优势已经出现在右侧。对6岁以下儿童进行进一步的研究，可以准确地观察视觉认知半球优势的发展变化。

In order to determine the dominant hemisphere of visual recognition and examine the developmental changes of the hemispheric dominance, event-related potentials (ERPs) were recorded in 20 normal adlescence (21-45 years of age) and 40 normal children (6-12 years of age). Visual stimuli of verbal ("Kana") and non-verbal ("Dot" in space and "Face") were presented using a tachistoscope and "oddball" paradigm.In normal adlescence (right handers), the P300 amplitude in verbal stimulation to right-visual field were higher than those to left-visual field. On the other hand, the P300 amplitude in non-verbal stimulation to left-visual field were higher than those to right-visual field. These findings suggest that P300 to the tachistoscopic visual stimuli could determine the hemispheric dominance. In normal right-handed adlescence, dominant hemisphere of verbal recognition present in the left and that of nonverbal recognition in the right.In normal right-handed children elder than 6 years of age, the P300 amplitude in verbal stimulation to right-visual field were also higher than those to left-visual field. The P300 amplitude in non-verbal stimulation "Dot" to left-visual field were higher than those to right-visual field in the children elder than 8 years of age. These findings suggest that hemispheric dominance of verbal recognition had already presented in the left in the children elder than 6 years of age and that of non-verbal recognition presented in the right in the children elder than 8 years of age.Further study in the children younger than 6 years of age would give the precise observation of the developmental change of hemispheric dominance of visual recognition.