Ciçek Metehan, Gitelman Darren, Hurley Robert S E, Nobre Anna, Mesulam Marsel
Cognitive Neurology and Alzheimer's Disease Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Cereb Cortex. 2007 Dec;17(12):2892-8. doi: 10.1093/cercor/bhm014. Epub 2007 Mar 6.
Neurologically intact volunteers participated in a functional magnetic resonance imaging experiment that simulated the unilateral (focal) and bilateral (global) stimulations used to elicit extinction in patients with hemispatial neglect. In peristriate areas, attentional modulations were selectively sensitive to contralaterally directed attention. A higher level of mapping was observed in the intraparietal sulcus (IPS), inferior parietal lobule (IPL), and inferior frontal gyrus (IFG). In these areas, there was no distinction between contralateral and ipsilateral focal attention, and the need to distribute attention globally led to greater activity than either focal condition. These physiological characteristics were symmetrically distributed in the IPS and IFG, suggesting that the effects of unilateral lesions in these 2 areas can be compensated by the contralateral hemisphere. In the IPL, the greater activation by the bilateral attentional mode was seen only in the right hemisphere. Its contralateral counterpart displayed equivalent activations when attention was distributed to the right, to the left, or bilaterally. Within the context of this experiment, the IPL of the right hemisphere emerged as the one area where unilateral lesions can cause the most uncompensated and selective impairment of global attention (without interfering with unilateral attention to either side), giving rise to the phenomenon of extinction.
神经系统完好的志愿者参与了一项功能磁共振成像实验，该实验模拟了用于引发半侧空间忽视患者消退现象的单侧（局部）和双侧（整体）刺激。在纹状周区域，注意力调制对 contralaterally 定向的注意力具有选择性敏感性。在顶内沟（IPS）、顶下小叶（IPL）和额下回（IFG）观察到更高水平的映射。在这些区域，对侧和同侧局部注意力之间没有区别，并且全局分配注意力的需求导致的活动比任何一种局部情况都更大。这些生理特征在 IPS 和 IFG 中对称分布，表明这两个区域单侧损伤的影响可以由对侧半球补偿。在 IPL 中，双侧注意力模式引起的更大激活仅在右半球可见。当注意力分配到右侧、左侧或双侧时，其对侧对应区域显示出等效的激活。在该实验的背景下，右半球的 IPL 成为单侧损伤可导致最无法补偿和选择性的全局注意力受损（而不干扰对任何一侧的单侧注意力）的一个区域，并引发消退现象。 注：原文中“contralaterally”可能拼写有误，推测可能是“contralateral”（对侧的） 。
