Rotman Research Institute - Baycrest Center, Toronto, Canada.
Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
Hum Brain Mapp. 2019 Feb 15;40(3):818-832. doi: 10.1002/hbm.24414. Epub 2018 Oct 29.
The well-established right visual field (RVF-lh) advantage in word recognition is commonly attributed to the typical left hemisphere dominance in language; words presented to the LVF-rh are processed less efficiently due to the need for transcallosal transfer from the right to left hemisphere. The exact stage for this hemispheric transfer is currently unsettled. Some studies suggest that transfer occurs at very early stages between primary visual regions, whereas other studies suggest that transfer occurs between the left visual word form area and its right hemisphere homolog. This study explores these conflicting accounts and finds evidence for both. Participants conducted a lateralized lexical decision task with both unilateral and bilateral display conditions. Connectivity analyses were conducted from magnetoencephalography signals that were localized to the left middle occipital gyrus (LMOG), right middle occipital gyrus (RMOG), left visual word form area (LVWFA), and right visual word form area (RVWA). Results from unilateral trials showed asymmetrical interhemispheric connectivity from the RMOG to LMOG and symmetrical interhemispheric connectivity between the LVWFA and RVWFA. Furthermore, bilateral presentations led to reduced interhemispheric connectivity between both homologous region of interest pairs. Together, these results suggest that lateralized word recognition involves multiple stages of interhemispheric interactions and that these interactions are reduced with bilateral displays.
右视野（RVF-lh）在单词识别中具有明显优势，这通常归因于语言中典型的左半球优势；呈现给左视野（LVF-rh）的单词由于需要从右半球经胼胝体向左侧转移，因此处理效率较低。目前，这种半球间转移的确切阶段尚未确定。一些研究表明，转移发生在初级视觉区域之间的早期阶段，而另一些研究表明，转移发生在左视觉词形区与其右侧半球同源区之间。本研究探讨了这些相互矛盾的观点，并发现了两者都存在的证据。参与者在单侧和双侧显示条件下进行了侧化词汇决策任务。从定位于左中枕回（LMOG）、右中枕回（RMOG）、左视觉词形区（LVWFA）和右视觉词形区（RVWA）的脑磁图信号进行了连通性分析。单侧试验的结果表明，RMOG 到 LMOG 的不对称性跨半球连接和 LVWFA 和 RVWFA 之间的对称性跨半球连接。此外，双侧呈现导致两个同源感兴趣区对之间的跨半球连接减少。总之，这些结果表明，侧化单词识别涉及多个跨半球相互作用的阶段，并且这些相互作用在双侧显示时会减少。
