Hilgetag C C, Théoret H, Pascual-Leone A
Boston University School of Medicine, Department of Anatomy and Neurobiology, 700 Albany Street W746, Boston, Massachusetts 02118, USA.
Nat Neurosci. 2001 Sep;4(9):953-7. doi: 10.1038/nn0901-953.
The breakdown of attentional mechanisms after brain damage can have drastic behavioral consequences, as in patients suffering from spatial neglect. While much research has concentrated on impaired attention to targets contralateral to sites of brain damage, here we report the ipsilateral enhancement of visual attention after repetitive transcranial magnetic stimulation (rTMS) of parietal cortex at parameters known to reduce cortical excitability. Normal healthy subjects received rTMS (1 Hz, 10 mins) over right or left parietal cortex. Subsequently, detection of visual stimuli contralateral to the stimulated hemisphere was consistently impaired when stimuli were also present in the opposite hemifield, mirroring the extinction phenomenon commonly observed in neglect patients. Additionally, subjects' attention to ipsilateral targets improved significantly over normal levels. These results underline the potential of focal brain dysfunction to produce behavioral improvement and give experimental support to models of interhemispheric competition in the distributed brain network for spatial attention.
脑损伤后注意力机制的瓦解会产生严重的行为后果，就像患有空间忽视症的患者那样。虽然许多研究都集中在对脑损伤部位对侧目标的注意力受损上，但在此我们报告，在已知会降低皮质兴奋性的参数下，对顶叶皮质进行重复经颅磁刺激（rTMS）后，视觉注意力会出现同侧增强。正常健康受试者接受右侧或左侧顶叶皮质的rTMS（1赫兹，10分钟）。随后，当刺激半球对侧的视觉刺激在对侧半视野中也存在时，对其的检测持续受损，这与在忽视症患者中常见的消退现象相似。此外，受试者对同侧目标的注意力显著高于正常水平。这些结果强调了局灶性脑功能障碍产生行为改善的潜力，并为空间注意力分布式脑网络中半球间竞争模型提供了实验支持。
