Nguyen Thomas, Kuntzelman Karl, Miskovic Vladimir
Department of Psychology, State University of New York at Binghamton, Binghamton, New York; and.
Department of Psychology, State University of New York at Binghamton, Binghamton, New York; and
J Neurophysiol. 2017 Jul 1;118(1):344-352. doi: 10.1152/jn.00129.2017. Epub 2017 Apr 26.
The rhythmic delivery of visual stimuli evokes large-scale neuronal entrainment in the form of steady-state oscillatory field potentials. The spatiotemporal properties of stimulus drive appear to constrain the relative degrees of neuronal entrainment. Specific frequency ranges, for example, are uniquely suited for enhancing the strength of stimulus-driven brain oscillations. When it comes to the nature of the visual stimulus itself, studies have used a plethora of inputs ranging from spatially unstructured empty fields to simple contrast patterns (checkerboards, gratings, stripes) and complex arrays (human faces, houses, natural scenes). At present, little is known about how the global spatial statistics of the input stimulus influence entrainment of scalp-recorded electrophysiological signals. In this study, we used rhythmic entrainment source separation of scalp EEG to compare stimulus-driven phase alignment for distinct classes of visual inputs, including broadband spatial noise ensembles with varying second-order statistics, natural scenes, and narrowband sine-wave gratings delivered at a constant flicker frequency. The relative magnitude of visual entrainment was modulated by the global properties of the driving stimulus. Entrainment was strongest for pseudo-naturalistic broadband visual noise patterns in which luminance contrast is greatest at low spatial frequencies (a power spectrum slope characterized by 1/ƒ). Rhythmically modulated visual stimuli entrain the activity of neuronal populations, but the effect of global stimulus statistics on this entrainment is unknown. We assessed entrainment evoked by ) visual noise ensembles with different spectral slopes, ) complex natural scenes, and ) narrowband sinusoidal gratings. Entrainment was most effective for broadband noise with naturalistic luminance contrast. This reveals some global properties shaping stimulus-driven brain oscillations in the human visual system.
视觉刺激的节律性传递会以稳态振荡场电位的形式诱发大规模神经元同步化。刺激驱动的时空特性似乎会限制神经元同步化的相对程度。例如，特定的频率范围特别适合增强刺激驱动的脑振荡强度。关于视觉刺激本身的性质，研究使用了大量的输入，从空间无结构的空白场到简单的对比度模式（棋盘格、光栅、条纹）以及复杂阵列（人脸、房屋、自然场景）。目前，关于输入刺激的全局空间统计如何影响头皮记录的电生理信号的同步化知之甚少。在本研究中，我们使用头皮脑电图的节律性同步源分离来比较不同类别的视觉输入的刺激驱动相位对齐，包括具有不同二阶统计量的宽带空间噪声集合、自然场景以及以恒定闪烁频率呈现的窄带正弦波光栅。视觉同步的相对幅度受到驱动刺激的全局特性的调节。对于伪自然主义宽带视觉噪声模式，同步最强，其中亮度对比度在低空间频率处最大（以1/ƒ为特征的功率谱斜率）。节律性调制的视觉刺激会使神经元群体的活动同步，但全局刺激统计对这种同步的影响尚不清楚。我们评估了由（1）具有不同频谱斜率的视觉噪声集合、（2）复杂自然场景和（3）窄带正弦光栅诱发的同步。对于具有自然主义亮度对比度的宽带噪声，同步最为有效。这揭示了一些塑造人类视觉系统中刺激驱动脑振荡的全局特性。
