Abstract The neural mechanisms underlying spontaneous perceptual switching during binocular rivalry remain incompletely understood. Current accounts emphasise either slow accumulation of adaptation in stimulus-driven pathways or top-down attentional fluctuations, but neither provides a principled account of what happens to the global organisation of neural oscillations in the seconds preceding a switch. Here we analyse EEG data from 29 healthy participants performing a binocular rivalry task, computing a novel set of spatial pattern stability metrics (Sγ) across five canonical frequency bands (δ, θ, α, β, γ) in a sliding window of 500ms. We compare epochs preceding perceptual switches with matched control epochs drawn from the middle of stable perceptual periods, eliminating the motor preparation confound present in conventional switch-versus-stable designs. We find that the period preceding perceptual switches is characterised by a stable and significant increase in the hierarchical decoupling gradient: the difference in spatial pattern stability between fast bands (α, β, γ) and slow bands (δ, θ). Specifically, fast-band stability exceeds slow-band stability more strongly before switches than during stable dominance (Early: d=+0.989, p<0.001; Mid: d=+0.740, p<0.001; Late: d=+0.753, p<0.001; all windows, N=29). This pattern is consistent with a theoretical framework of progressive Negative Space Encoding (NSE), in which slow oscillations serve as global constraint anchors for faster local processing. We interpret the pre-switch state as one of hierarchical decoupling: local oscillatory patterns (α, β, γ) maintain spatial organisation without adequate global scaffolding (δ, θ), creating an unstable representational state that resolves through perceptual reorganisation. These findings suggest that phenomenal transitions in rivalry are not merely sensory adaptation events but reflect a breakdown of the hierarchical constraint structure that stabilises the current percept. Keywords: binocular rivalry; neural oscillations; cross-frequency coupling; perceptual switching; hierarchical decoupling; Negative Space Encoding; spatial efficiency; phenomenal transition; EEG
Alastair Waterman (Thu,) studied this question.