Yoon, Yosun

Cognitive flexibility is crucial for efficient goal-directed behavior, especially in rapidly changing environments. While recent studies have consistently shown enhanced theta power and synchronization in the frontoparietal network during flexible task-switching, direct evidence establishing a causal link between theta-rhythm brain oscillation and cognitive flexibility remains limited. In this study, we applied transcranial alternating current stimulation (tACS) to the frontoparietal network at a theta frequency (6 Hz) with a phase difference of either 0° (inphase) or 180° (antiphase) to explore its impact on task-switching performance. The results showed no significant tACS modulation effects on switch costs or neural oscillatory synchronization in the frontoparietal network. However, a consistent negative correlation was observed between frontoparietal theta power in the early time window of cue-target interval and task switching performance, implying the close relationship between proactive control in task switching and frontoparietal theta activities.

Interocular grouping during binocular rivalry occurs when two images concurrently presented to two eyes are combined as a coherent pattern as if perceptual experience follows Gestalt grouping principles. The present study investigated what determines rivalry dynamics (perceptual experience of monocular stimuli and interocular grouping) by examining individual differences. Specifically, the effect of eye-of-origin and pattern coherence on percepts during rivalry were individually assessed using pairs of stimuli that induce either monocularly-driven (monocular coherence condition) or interocularly-driven (interocular coherence condition) coherent percepts. We found that the degree of perceiving complete, coherent stimuli was consistent within individuals regardless of conditions, indicating that individual differences in experiencing interocular grouping were explained by pattern coherence, rather than eye-of-origin information. In addition, we found that individuals who experience binocularly presented pattern motion more perceived interocularly-coherent stimuli more. This result suggests that a potential common mechanism may mediate binocular integration of visual information during binocular rivalry.