Antimo Buonocore¹ (), Celeste Cafaro¹, Alessio Fracasso²; ¹Suor Orsola Benincasa University, Italy, ²University of Glasgow

In natural environments, stimuli often recur over time and space, requiring the visual system to adapt to predictable patterns while maintaining sensitivity to novel information. Within the visual system, neural responses to repeated stimuli at the same location in rapid succession often diminish (neuronal adaptation). However, it is less clear how these adaptation mechanisms persist over longer timescales as behavior evolves, and whether different modalities adapt differently. To address this, we developed a free-viewing paradigm in which participants explored a screen displaying simple shapes, such as squares and circles, for about eight seconds and compared their relative quantities. During visual inspection, a black circle was flashed five times consecutively, either in the fovea or the periphery, four degrees left of the fovea. Each flash was separated by a minimum of 700 ms and a maximum of 1200 ms. Across both retinal locations, saccadic inhibition occurred approximately 100 ms after flash onset. As expected, foveal transients elicited stronger inhibition than peripheral ones. We further examined whether initial transients were more effective at inducing inhibition than subsequent ones. While the magnitude and latency of inhibition remained consistent across flashes, the rebound phase —characterized by the reinstatement of saccades— showed signs of adaptation. Specifically, the proportion of saccades following the first transient decreased for subsequent flashes. This effect was more pronounced for peripheral stimuli, though a similar trend was observed for foveal ones. These findings suggest that during rapid successions of stimuli, the visual system sustains a robust inhibitory response to transients. However, the recovery of oculomotor plans adapts over time, reducing the likelihood of repeated motor execution, particularly for peripheral stimuli. This highlights the dynamic interplay between attentional prioritization and motor planning, where the visual system balances responsiveness to novel information with the efficient suppression of redundant signals in complex environments.

Acknowledgements: A.B. and C.C. were supported by a grant from the Italian Minister of Research and University (PRIN 2022_PNRR-P2022ST78T)