Department of Neuroscience, Imaging, and Clinical Science, Institute of Advanced Biomedical Technologies (ITAB), University "G. D'Annunzio", Via dei Vestini 33, Chieti 66100, Italy.
Department of Neurology, Radiology, Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, MO 63130, USA.
Cereb Cortex. 2017 Oct 1;27(10):4815-4822. doi: 10.1093/cercor/bhw278.
Alpha (8-12 Hz) power desynchronization is strongly associated to visual perception but has been observed in a large variety of tasks, indicating a general role in task anticipation. We previously reported in human observers that interference by repetitive transcranial magnetic stimulation (rTMS) of core regions of the dorsal attention network (DAN) disrupts both anticipatory alpha desynchronization and performance during a visuospatial attention (VSA) task. Here, we test the hypothesis that alpha desynchronization is task specific, and can be selectively modulated by interfering with activity in different higher-order parietal regions. We contrast the effects of rTMS on alpha rhythms and behavior on 2 different tasks: a VSA and a semantic decision task, by targeting the posterior intraparietal sulcus (pIPS), a core region of the DAN, or the angular gyrus (AG), a core region of the default mode network (DMN). We found that both performance and anticipatory alpha desynchronization were affected by stimulation of IPS only during VSA, and of AG only during semantic decisions. These findings indicate the existence of multiple dedicated parietal channels for the modulation of anticipatory alpha rhythms, which in turn reflect task-specific modulation of excitability in human parieto-occipital cortex.
阿尔法（8-12Hz）功率去同步化与视觉感知强烈相关，但在各种任务中都有观察到，表明其在任务预期中具有普遍作用。我们之前在人类观察者中报告说，背侧注意网络（DAN）核心区域的重复经颅磁刺激（rTMS）干扰会破坏视觉空间注意（VSA）任务中的预期阿尔法去同步化和表现。在这里，我们假设阿尔法去同步化是特定于任务的，并且可以通过干扰不同的高级顶叶区域的活动来选择性地调节。我们通过针对后顶内沟（pIPS），即 DAN 的核心区域，或角回（AG），即默认模式网络（DMN）的核心区域，来对比 rTMS 对阿尔法节律和行为的影响在 2 个不同的任务：VSA 和语义决策任务。我们发现，只有在 VSA 期间，IPS 的刺激才会影响性能和预期的阿尔法去同步化，而只有在语义决策期间，AG 的刺激才会影响性能和预期的阿尔法去同步化。这些发现表明，存在多个用于调节预期阿尔法节律的专用顶叶通道，而这些通道又反映了人类顶枕叶皮层中针对特定任务的兴奋性调节。
