The relative contribution of noise and adaptation to competition during tri-stable motion perception
Journal of Vision
Association for Research in Vision and Ophthalmology (ARVO)
Open access. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License: https://creativecommons.org/licenses/by-nc-nd/4.0/
Animals exploit antagonistic interactions for sensory processing and these can cause oscillations between competing states. Ambiguous sensory inputs yield such perceptual multistability. Despite numerous empirical studies using binocular rivalry or plaid pattern motion, the driving mechanisms behind the spontaneous transitions between alternatives remain unclear. In the current work, we used a tristable barber pole motion stimulus combining empirical and modeling approaches to elucidate the contributions of noise and adaptation to underlying competition. We first robustly characterized the coupling between perceptual reports of transitions and continuously recorded eye direction, identifying a critical window of 480 ms before button presses, within which both measures were most strongly correlated. Second, we identified a novel nonmonotonic relationship between stimulus contrast and average perceptual switching rate with an initially rising rate before a gentle reduction at higher contrasts. A neural fields model of the underlying dynamics introduced in previous theoretical work and incorporating noise and adaptation mechanisms was adapted, extended, and empirically validated. Noise and adaptation contributions were confirmed to dominate at the lower and higher contrasts, respectively. Model simulations, with two free parameters controlling adaptation dynamics and direction thresholds, captured the measured mean transition rates for participants. We verified the shift from noise-dominated toward adaptation-driven in both the eye direction distributions and intertransition duration statistics. This work combines modeling and empirical evidence to demonstrate the signal-strength–dependent interplay between noise and adaptation during tristability. We propose that the findings generalize beyond the barber pole stimulus case to ambiguous perception in continuous feature spaces.
AIM was supported by the Aix-Marseille Université Foreign Postdoctoral Fellowship 2011, and ANR grants (Visafix, ANR-1D-blan-1432, and SPEED ANR-13-SHS2-0006) awarded to GSM. JR, OF, and PK were partially funded by ERC grant no 227747 (NERVI) and the EC IP project FP7-ICT-2011-8 no. 318723 (MatheMACS). GSM, OF, PK, and JR also acknowledge funding by the EU FP7 grant no 269921 (BRAINSCALES).
This is the final version of the article. Available from ARVO via the DOI in this record
Vol. 16 (15), article 6