Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, United Kingdom.
J Neurosci. 2013 Feb 27;33(9):4002-10. doi: 10.1523/JNEUROSCI.4675-12.2013.
Although it is increasingly accepted that temporal expectation can modulate early perceptual processing, the underlying neural computations remain unknown. In the present study, we combined a psychophysical paradigm with electrophysiological recordings to investigate the putative contribution of low-frequency oscillatory activity in mediating the modulation of visual perception by temporal expectation. Human participants judged the orientation of brief targets (visual Gabor patterns tilted clockwise or counterclockwise) embedded within temporally regular or irregular streams of noise-patches used as temporal cues. Psychophysical results indicated that temporal expectation enhanced the contrast sensitivity of visual targets. A diffusion model indicated that rhythmic temporal expectation modulated the signal-to-noise gain of visual processing. The concurrent electrophysiological data revealed that the phase of delta oscillations overlying human visual cortex (1-4 Hz) was predictive of the quality of target processing only in regular streams of events. Moreover, in the regular condition, the optimum phase of these perception-predictive oscillations occurred in anticipation of the expected events. Together, these results show a strong correspondence between psychophysical and neurophysiological data, suggesting that the phase entrainment of low-frequency oscillations to external sensory cues can serve as an important and flexible mechanism for enhancing sensory processing.
尽管越来越多的人认为时间预期可以调节早期的感知处理，但潜在的神经计算仍然未知。在本研究中，我们结合了心理物理学范式和电生理记录来研究低频振荡活动在介导时间预期对视觉感知的调制中的可能作用。人类参与者判断了短暂目标（顺时针或逆时针倾斜的视觉 Gabor 模式）的方向，这些目标嵌入在用作时间线索的规则或不规则的噪声补丁流中。心理物理学结果表明，时间预期增强了视觉目标的对比度敏感度。扩散模型表明，有节奏的时间预期调节了视觉处理的信噪比增益。并发的电生理数据表明，覆盖人类视觉皮层（1-4 Hz）的 delta 振荡的相位仅在规则的事件流中对目标处理的质量具有预测性。此外，在规则条件下，这些感知预测性振荡的最佳相位出现在预期事件之前。总之，这些结果显示了心理物理学和神经生理学数据之间的强对应关系，表明低频振荡对外部感觉线索的相位锁定可以作为增强感觉处理的重要且灵活的机制。
