Real-time gating of cyclic brain activity: Evidence from modulations of binocular rivalry induced by rapid stimulus interruptions
According to widespread opinion, perceptual-cognitive information processing is founded on systems of mutually tuned neural oscillations flexibly adapting to environmental constraints and task demands. From directly observable phenomena ubiquitous in the brain, this view seems to be well-supported. However, it ignores important prerequisites of stability, selectivity and protection against disturbances. Regular timing patterns surfacing in resonant states of the brain suggest that they are accomplished by delay-based gating mechanisms whose action in support of precise temporal coordination hardly ever comes directly into sight. Exploring the effects of rapid stimulus interruptions (25 to 125 Hz) on binocular rivalry, we demonstrate â€“ for the first time for such a large range â€“ fine-grained cyclic modulations that are evenly spaced in time rather than frequency. Our results support the view that recurrent chains of neural delays play a leading role in the selective amplification of preferred cycles. This agrees with range constraints specified by the time-quantum approach, TQM.