INTRODUCTION: Scene perception relies on parallel subcortical pathways having different temporal dynamics and processing different kinds of information. Specifically, low spatial frequencies (LSF), conveying the global ‘gist’ of a scene, are handled by the rapid magnocellular pathway, while high spatial frequencies (HSF), carrying scene details, pass through the slower parvocellular pathway. Here, we investigated how these pathways interact. To this end, we harnessed perceptual rivalry – a state occurring when the brain receives conflicting information and resulting in perceiving competing interpretations of the same sensory input alternately.

AIM(S): We aim to induce perceptual rivalry between naturalistic scenes and use it to determine how stimulus presentation time modulates the processing of HSF and LSF.

METHOD(S): We developed ‘hybrid’ stimuli by superimposing scenes from two categories. In each hybrid, one category contained only LSF components, while the other only HSF. In the first experiment, involving 15 participants and a presentation time of 133 ms, we used a staircase procedure adjusting intensities of both categories for each observer so that the hybrids elicited perceptual rivalry (defined as a ~50% chance of perceiving each category). In a follow-up experiment, we tested whether shorter presentation times shift the balance between LSF and HSF components.

RESULTS: The first experiment demonstrated that the staircase procedure successfully induces perceptual rivalry. Ongoing analyses of the data from the second experiment suggest that shorter times significantly alter the intensities required to achieve the 50/50 perceptual equilibrium between the LSF and HSF.

CONCLUSIONS: Analysing the requirements for rivalry across temporal scales reveals how the brain balances competing representations under varying time constraints. Consequently, it offers insights into the functional properties of visual awareness and the temporal profiles of LSF and HSF processing.

FINANCIAL SUPPORT: This study was funded by the Sonata Bis grant (2022/46/E/HS6/00150) awarded to the author M. B. by the National Science Centre, Poland.