MICROSACCADES DIRECTION AS A BEHAVIORAL READOUT OF SENSORY PREDICTIONS DURING BISTABLE APPARENT MOTION PERCEPTION

Perception is understood as an inferential process arising from interactions between bottom-up sensory signals and top-down predictions. Recent theoretical (Madden et al. TICS2022) and anatomical (Lei et al. Cell2025) work suggests that the claustrum plays a central role in this process by integrating distributed cortical signals and contributes to hierarchical cortical processing during perception.
We investigate behavioral markers of predictive processing in macaque monkeys performing a bistable apparent motion task (Pizzuti et al. BrainStructFunct2025), a paradigm in which perceptual experience is internally generated and dissociated from changes in physical stimulus input, allowing us to minimize confounds related to retinal adaptation.
We focus here on microsaccades, small fixational eye movements that are closely linked to attentional allocation and perceptual updating (Hafed and Clark, VisRes2002). Using unsupervised clustering (Otero-Millan et al. JoV2014), we identified their direction during physical motion. During vertical (horizontal) physical motion, microsaccades direction is preferentially distributed along the vertical (horizontal) axis. This will be used to decode what apparent motion the monkey perceives during the ambiguous motion.
These behavioral results are intended to inform and constrain future electrophysiological experiments in monkeys and neuroimaging experiments in humans, in which large-scale single unit recordings and high-field laminar fMRI will be exploited to investigate claustral and cortical involvement using the same perceptual paradigm.
Together, this work provides a behavioral framework for investigating predictive processing in human and NHP, at different spatiotemporal levels to assess claustral involvement during perceptual inference.
Contact: julien.vezoli@inserm.fr; henry.kennedy@inserm.fr
Funding: ANR-22-CE92-0010-01; ERC-2023-Adv101142153PREDICTION; ANR-25-CE37-7332-01