Hemispheric specialization for global and local processing: The effect of stimulus category
Hemispheric specialization for global and local processing: The effect of stimulus category
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DOI：
10.1098/rspb.1997.0070
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发表时间：
1997-04-22
影响因子：
4.7
通讯作者：
Dolan, RJ
中科院分区：
文献类型：
--
作者：
Fink, GR;Marshall, JC;Dolan, RJ
神经心理学证据表明，复杂视觉场景的全局方面优先由右半球处理，局部方面优先由左半球处理。使用基于字母的分层刺激（Navon 图），我们最近在定向注意任务中证明了局部处理期间左前纹状皮层和全局处理期间右前纹状皮层的侧化神经活动（通过正电子发射断层扫描评估）。此外，颞顶叶皮层在注意力分散任务中被严重激活，该任务涉及改变基于字母的分层刺激的局部和全局水平之间的目标切换数量。人们对这些刺激类别是否影响这种半球偏侧化知之甚少。我们现在提供来自正电子发射断层扫描的大脑活动数据，这些数据是在基于对象的分层刺激的局部或全局处理过程中扫描的正常受试者的大脑活动数据。我们再次观察到前纹状皮层神经活动的注意力调节。现在，用于局部处理的右侧激活更大，用于全局处理的左侧激活更大，这与基于字母的刺激所看到的相反。结果表明，在全局和局部处理过程中，前纹状体区域的相对差异半球激活被刺激类别所改变。
Neuropsychological evidence indicates that the global aspect of complex visual scenes is preferentially processed by the right hemisphere, and local aspects are preferentially processed by the left hemisphere. Using letter-based hierarchical stimuli (Navon figures), we recently demonstrated, in a directed-attention task, lateralized neural activity (assessed by positron emission tomography) in the left prestriate cortex during local processing, and in the right prestriate cortex during global processing. Furthermore, temporal-parietal cortex was critically activated bilaterally in a divided-attention task that involved varying the number of target switches between local and global levels of letter-based hierarchical stimuli. Little is known about whether such stimulus categories influence such hemispheric lateralization. We now present data on brain activity, derived from positron emission tomography, in normal subjects scanned during either local or global processing of object-based hierarchical stimuli. We again observe attentional modulation of neural activity in prestriate cortex. There is now greater right-sided activation for local processing and greater left-sided activation for global processing, which is the opposite of that seen with letter-based stimuli. The results suggest that the relative differential hemispheric activations in the prestriate areas during global and local processing are modified by stimulus category.