Wang Jiaojian, Tian Yanghua, Wang Mengzhu, Cao Long, Wu Huawang, Zhang Yun, Wang Kai, Jiang Tianzi
Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 625014, China.
Department of Neurology, the First Hospital of Anhui Medical University, Hefei, 230022, China.
Brain Imaging Behav. 2016 Dec;10(4):1029-1037. doi: 10.1007/s11682-015-9460-y.
The lateralization of visuospatial attention has been well investigated and demonstrated to be primarily resulting from unbalanced interaction between interhemispheric fronto-parietal networks in previous studies. Many recent studies of top-down attention have reported the neural signatures of its effects within visual cortex and identified its causal basis. However, the relationship between top-down networks and asymmetric visuospatial attention has not been well studied. In the current study, we aimed to explore the relationship between top-down connectivity and asymmetric visuospatial ability by using repetitive transcranial magnetic stimulation (rTMS) and resting-state functional connectivity (RSFC) analyses. We used rTMS and RSFC to model the virtual lesion to assess the behavioral performances in visuospatial attention shifting and to identify the behavior-related top-down functional connectivities, respectively. Furthermore, we also investigated the top-down connectivity in neglect patients to validate the RSFC findings. RSFC analyses in healthy subjects and neglect patients consistently revealed that asymmetric visuospatial ability and visuospatial neglect were closely related to the bias of top-down functional connectivity between posterior superior parietal lobule (SPL) and V1. Our findings indicate that stronger top-down connectivity has stronger dominance on its corresponding visual field. We argue that an asymmetric top-down network may represent a possible neurophysiological substrate for the ongoing functional asymmetry of visuospatial attention, and its interhemispheric unbalanced interaction could contribute to the clinical manifestations of visuospatial neglect.
以往的研究对视觉空间注意力的偏侧化进行了充分的调查，并证明其主要源于半球间额顶叶网络之间的不平衡相互作用。最近许多关于自上而下注意力的研究报告了其在视觉皮层内的神经特征，并确定了其因果基础。然而，自上而下的网络与不对称视觉空间注意力之间的关系尚未得到充分研究。在本研究中，我们旨在通过使用重复经颅磁刺激（rTMS）和静息态功能连接（RSFC）分析来探索自上而下的连接性与不对称视觉空间能力之间的关系。我们分别使用rTMS和RSFC对虚拟损伤进行建模，以评估视觉空间注意力转移中的行为表现，并识别与行为相关的自上而下的功能连接。此外，我们还研究了忽视患者的自上而下连接性，以验证RSFC的结果。对健康受试者和忽视患者的RSFC分析一致表明，不对称视觉空间能力和视觉空间忽视与后顶上小叶（SPL）和V1之间自上而下功能连接的偏差密切相关。我们的研究结果表明，更强的自上而下连接性对其相应的视野具有更强的主导作用。我们认为，不对称的自上而下网络可能代表了视觉空间注意力持续功能不对称的一种可能的神经生理基础，其半球间的不平衡相互作用可能导致视觉空间忽视的临床表现。
