Department of Intelligent Interaction Technology, Graduate School of Systems and Information Engineering, University of Tsukuba Tsukuba, Japan ; Rhythm-based Brain Information Processing Unit, RIKEN BSI-TOYOTA Collaboration Center Ibaraki, Japan ; Laboratory for Advanced Brain Signal Processing, RIKEN Brain Science Institute Saitama, Japan.
Rhythm-based Brain Information Processing Unit, RIKEN BSI-TOYOTA Collaboration Center Ibaraki, Japan ; Laboratory for Advanced Brain Signal Processing, RIKEN Brain Science Institute Saitama, Japan.
Front Psychol. 2014 Mar 18;5:200. doi: 10.3389/fpsyg.2014.00200. eCollection 2014.
In humans, theta phase (4-8 Hz) synchronization observed on electroencephalography (EEG) plays an important role in the manipulation of mental representations during working memory (WM) tasks; fronto-temporal synchronization is involved in auditory-verbal WM tasks and fronto-parietal synchronization is involved in visual WM tasks. However, whether or not theta phase synchronization is able to select the to-be-manipulated modalities is uncertain. To address the issue, we recorded EEG data from subjects who were performing auditory-verbal and visual WM tasks; we compared the theta synchronizations when subjects performed either auditory-verbal or visual manipulations in separate WM tasks, or performed both two manipulations in the same WM task. The auditory-verbal WM task required subjects to calculate numbers presented by an auditory-verbal stimulus, whereas the visual WM task required subjects to move a spatial location in a mental representation in response to a visual stimulus. The dual WM task required subjects to manipulate auditory-verbal, visual, or both auditory-verbal and visual representations while maintaining auditory-verbal and visual representations. Our time-frequency EEG analyses revealed significant fronto-temporal theta phase synchronization during auditory-verbal manipulation in both auditory-verbal and auditory-verbal/visual WM tasks, but not during visual manipulation tasks. Similarly, we observed significant fronto-parietal theta phase synchronization during visual manipulation tasks, but not during auditory-verbal manipulation tasks. Moreover, we observed significant synchronization in both the fronto-temporal and fronto-parietal theta signals during simultaneous auditory-verbal/visual manipulations. These findings suggest that theta synchronization seems to flexibly connect the brain areas that manipulate WM.
在人类中，脑电图（EEG）上观察到的θ相位（4-8 Hz）同步在工作记忆（WM）任务中对心理表象的操作起着重要作用；额颞同步涉及听觉言语 WM 任务，而额顶同步涉及视觉 WM 任务。然而，θ相位同步是否能够选择要操作的模态尚不确定。为了解决这个问题，我们记录了正在执行听觉言语和视觉 WM 任务的受试者的 EEG 数据；我们比较了受试者在单独的 WM 任务中执行听觉言语或视觉操作时，或在同一 WM 任务中同时执行两种操作时的θ同步。听觉言语 WM 任务要求受试者计算听觉言语刺激呈现的数字，而视觉 WM 任务要求受试者在响应视觉刺激时在心理表象中移动空间位置。双重 WM 任务要求受试者在保持听觉言语和视觉表象的同时，对听觉言语、视觉或两者的表象进行操作。我们的时频 EEG 分析显示，在听觉言语和听觉言语/视觉 WM 任务中，在听觉言语操作期间，额颞区有明显的θ相位同步，但在视觉操作任务中则没有。同样，我们观察到在视觉操作任务期间存在明显的额顶区θ相位同步，但在听觉言语操作任务中则没有。此外，在同时进行听觉言语/视觉操作时，我们观察到额颞区和额顶区θ信号都有明显的同步。这些发现表明，θ 同步似乎灵活地连接了操作 WM 的大脑区域。
