Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands.
J Cogn Neurosci. 2013 Aug;25(8):1332-42. doi: 10.1162/jocn_a_00402. Epub 2013 Apr 11.
Lesion studies in neglect patients have inspired two competing models of spatial attention control, namely, Heilman's "hemispatial" theory and Kinsbourne's "opponent processor" model. Both assume a functional asymmetry between the two hemispheres but propose very different mechanisms. Neuroimaging studies have identified a bilateral dorsal frontoparietal network underlying voluntary shifts of spatial attention. However, lateralization of attentional processes within this network has not been consistently reported. In the current study, we aimed to provide direct evidence concerning the functional asymmetry of the right and left FEF during voluntary shifts of spatial attention. To this end, we applied fMRI-guided neuronavigation to disrupt individual FEF activation foci with a longer-lasting inhibitory patterned TMS protocol followed by a spatial cueing task. Our results indicate that right FEF stimulation impaired the ability of shifting spatial attention toward both hemifields, whereas the effects of left FEF stimulation were limited to the contralateral hemifield. These results provide strong direct evidence for right-hemispheric dominance in spatial attention within frontal cortex supporting Heilman's "hemispatial" theory. This complements previous TMS studies that generally conform to Kinsbourne's "opponent processor" model after disruption of parietal cortex, and we therefore propose that both theories are not mutually exclusive.
忽略症患者的病变研究激发了两种竞争性的空间注意控制模型，即 Heilman 的“半球间”理论和 Kinsbourne 的“对立处理器”模型。这两种模型都假设两个半球之间存在功能不对称，但提出了非常不同的机制。神经影像学研究已经确定了一个双侧背侧额顶叶网络，该网络是自愿转移空间注意力的基础。然而，该网络中注意力过程的侧化并没有得到一致的报道。在目前的研究中，我们旨在提供关于右侧和左侧 FEF 在自愿转移空间注意力期间的功能不对称的直接证据。为此，我们应用 fMRI 引导的神经导航，使用持续时间更长的抑制性模式 TMS 方案破坏单个 FEF 激活焦点，然后进行空间提示任务。我们的结果表明，右侧 FEF 的刺激会损害向两个半视野转移空间注意力的能力，而左侧 FEF 的刺激的影响仅限于对侧视野。这些结果为额叶皮层中空间注意力的右半球优势提供了强有力的直接证据，支持 Heilman 的“半球间”理论。这与之前的 TMS 研究相补充，这些研究在破坏顶叶皮层后通常符合 Kinsbourne 的“对立处理器”模型，因此我们提出这两种理论并非相互排斥。
