Carl Christine, Hipp Joerg F, König Peter, Engel Andreas K
Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
Institute of Cognitive Science, University of Osnabrück, Albrechtstraße 28, 49069, Osnabrück, Germany.
Brain Topogr. 2016 Jan;29(1):130-48. doi: 10.1007/s10548-015-0426-6. Epub 2015 Feb 18.
Action generation relies on a widely distributed network of brain areas. However, little is known about the spatiotemporal dynamics of neuronal activity in the network that gives rise to voluntary action in humans. Here, we used magnetoencephalography (MEG) and source analysis (n = 15, 7 female subjects) to investigate the spectral signatures of human cortical networks engaged in active and intrinsically motivated viewing behavior. We compared neuronal activity of externally cued saccades with saccades to freely chosen targets. For planning and execution of both saccade types, we found an increase in gamma band (64-128 Hz) activity and a concurrent decrease in beta band (12-32 Hz) activity in saccadic control areas, including the intraparietal sulcus and the frontal eye fields. Guided compared to voluntary actions were accompanied by stronger transient increases in the gamma and low frequency (<16 Hz) range immediately following the instructional cue. In contrast, action selection between competing alternatives was reflected by stronger sustained fronto-parietal gamma increases that occurred later in time and persisted until movement execution. This sustained enhancement for free target selection was accompanied by a spatially widespread reduction of lower frequency power (~8-45 Hz) in parietal and extrastriate areas. Our results suggest that neuronal population activity in the gamma frequency band in a distributed network of fronto-parietal areas reflects the intrinsically driven process of selection among competing behavioral alternatives.
动作生成依赖于广泛分布的脑区网络。然而，对于在人类中引发自主动作的该网络中神经元活动的时空动态，我们却知之甚少。在此，我们使用脑磁图（MEG）和源分析（n = 15，7名女性受试者）来研究参与主动和内在动机性观看行为的人类皮层网络的频谱特征。我们将外部提示的扫视与向自由选择目标的扫视的神经元活动进行了比较。对于这两种扫视类型的计划和执行，我们发现在包括顶内沟和额叶眼区在内的扫视控制区域，γ波段（约64 - 128赫兹）活动增加，同时β波段（约12 - 32赫兹）活动减少。与自主动作相比，指导性动作在指令提示后紧接着在γ波段和低频（<16赫兹）范围内有更强的瞬时增加。相反，在相互竞争的选项之间进行动作选择表现为额叶 - 顶叶γ波段更强的持续增加，这种增加发生在稍后的时间并持续到动作执行。这种在自由目标选择时的持续增强伴随着顶叶和纹外区域低频功率（约8 - 45赫兹）在空间上的广泛降低。我们的结果表明，额叶 - 顶叶区域分布式网络中γ频段的神经元群体活动反映了在相互竞争的行为选项之间进行内在驱动的选择过程。
