Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany Universitäts-Augenklinik, Freiburg, Germany.
Psychophysiology. 2011 Apr;48(4):547-58. doi: 10.1111/j.1469-8986.2010.01087.x. Epub 2010 Aug 26.
Ambiguous figures induce sudden transitions between rivaling percepts. We investigated electroencephalogram frequency modulations of accompanying change-related de- and rebinding processes. Presenting the stimuli discontinously, we synchronized perceptual reversals with stimulus onset, which served as a time reference for averaging. The resultant gain in temporal resolution revealed a sequence of time-frequency correlates of the reversal process. Most conspicuous was a transient right-hemispheric gamma modulation preceding endogenous reversals by at least 200 ms. No such modulation occurred with exogenously induced reversals of unambiguous stimulus variants. Post-onset components were delayed for ambiguous compared to unambiguous stimuli. The time course of oscillatory activity differed in several respects from predictions based on binding-related hypotheses. The gamma modulation preceding endogenous reversals may indicate an unstable brain state, ready to switch.
歧义图形会在相互竞争的感知之间产生突然的转变。我们研究了伴随的变化相关去绑定和再绑定过程的脑电图频率调制。通过不连续地呈现刺激，我们将感知反转与刺激开始同步，这为平均提供了时间参考。时间分辨率的提高揭示了反转过程的时频相关序列。最明显的是，在至少 200 毫秒之前，右侧半球的伽马调制会出现短暂的瞬态，这种调制不会出现在具有明确刺激变体的外源性反转中。与明确刺激相比，歧义刺激的起始后成分延迟。与基于绑定相关假设的预测相比，振荡活动的时程在几个方面有所不同。在自发反转之前的伽马调制可能表明大脑状态不稳定，准备切换。
