Kizuk Sayeed A D, Mathewson Kyle E
University of Alberta.
J Cogn Neurosci. 2017 Mar;29(3):480-494. doi: 10.1162/jocn_a_01058. Epub 2016 Oct 19.
Oscillatory brain rhythms can bias attention via phase and amplitude changes, which modulate sensory activity, biasing information to be processed or ignored. Alpha band (7-14 Hz) oscillations lateralize with spatial attention and rhythmically inhibit visual activity and awareness through pulses of inhibition. Here we show that human observers' awareness of spatially unattended targets is dependent on both alpha power and alpha phase at target onset. Following a predictive directional cue, alpha oscillations were entrained bilaterally using repetitive visual stimuli. Subsequently, we presented either spatially cued or uncued targets at SOAs either validly or invalidly predicted in time by the entrainers. Temporal validity maximally modulated perceptual performance outside the spatial focus of attention and was associated with both increased alpha power and increased neural entrainment of phase in the hemisphere processing spatially unattended information. The results demonstrate that alpha oscillations represent a pulsating inhibition, which impedes visual processing for unattended space.
振荡性脑节律可通过相位和振幅变化来偏向注意力，这些变化会调节感觉活动，从而使要处理或忽略的信息产生偏差。阿尔法波段（7 - 14赫兹）振荡会随着空间注意力而发生偏侧化，并通过抑制脉冲有节奏地抑制视觉活动和意识。在此我们表明，人类观察者对空间上未被注意的目标的意识取决于目标出现时的阿尔法功率和阿尔法相位。在一个预测性方向线索之后，使用重复性视觉刺激双侧诱导入阿尔法振荡。随后，我们在由诱导刺激在时间上有效或无效预测的刺激呈现间隔（SOA）下，呈现空间上有线索提示或无线索提示的目标。时间有效性在注意力的空间焦点之外最大程度地调节了感知性能，并且与阿尔法功率增加以及处理空间上未被注意信息的半球中的相位神经同步增加有关。结果表明，阿尔法振荡代表一种脉动抑制，它会阻碍对未被注意空间的视觉处理。
