Blanc-Garin J, Faure S, Sabio P
U.A. au CNRS Cognition et Mouvement (1166), Groupement de Recherche en Neuropsychologie (CNRS 978), University of Aix-Marseille, France.
Brain Cogn. 1993 May;22(1):118-33. doi: 10.1006/brcg.1993.1028.
The objective of this study was to analyze dynamic aspects of right hemisphere implementation in processing visual images. Two tachistoscopic, divided visual field experiments were carried out on a partial split-brain patient with no damage to the right hemisphere. In the first experiment, image generation performance for letters presented in the right visual field (/left hemisphere) was undeniably optimal. In the left visual field (/right hemisphere), performance was no better than chance level at first, but then improved dramatically across stimulation blocks, in each of five successive sessions. This was interpreted as revealing the progressive spontaneous activation of the right hemisphere's competence not shown initially. The aim of the second experiment was to determine some conditions under which this pattern was obtained. The experimental design contrasted stimuli (words and pictures) and representational activity (phonologic and visuo-imaged processing). The right visual field (/left hemisphere: LH) elicited higher performance than the left visual field (/right hemisphere, RH) in the three situations where verbal activity was required. No superiority could be found when visual images were to be generated from pictures: parallel and weak improvement of both hemispheres was observed across sessions. Two other patterns were obtained: improvement in RH performance (although LH performance remained superior) and an unexpectedly large decrease in RH performance. These data are discussed in terms of RH cognitive competence and hemisphere implementation.
本研究的目的是分析右半球在处理视觉图像时的动态表现。对一名右半球未受损的部分裂脑患者进行了两项速示、视野分割实验。在第一个实验中，呈现于右视野（/左半球）的字母的图像生成表现无疑是最佳的。在左视野（/右半球），起初表现并不比随机水平好，但在随后连续五个阶段的每个阶段中，跨刺激块的表现都有显著改善。这被解释为揭示了右半球能力最初未表现出的逐渐自发激活。第二个实验的目的是确定获得这种模式的一些条件。实验设计对比了刺激（单词和图片）和表征活动（语音和视觉成像处理）。在需要语言活动的三种情况下，右视野（/左半球：LH）的表现高于左视野（/右半球，RH）。当要从图片生成视觉图像时，未发现优势：各阶段观察到两个半球的表现平行且微弱改善。还获得了另外两种模式：右半球表现改善（尽管左半球表现仍更优）以及右半球表现意外大幅下降。根据右半球认知能力和半球表现对这些数据进行了讨论。
