TY - JOUR T1 - Opponent surrounds explain diversity of contextual phenomena across visual modalities JF - bioRxiv DO - 10.1101/070821 SP - 070821 AU - David A. Mély AU - Thomas Serre Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/08/22/070821.abstract N2 - Context is known to affect how a stimulus is perceived. A variety of illusions have been attributed to contextual processing — from orientation tilt effects to chromatic induction phenomena, but their neural underpinnings remain poorly understood. Here, we present a recurrent network model of classical and extra-classical receptive fields that is constrained by the anatomy and physiology of the visual cortex. A key feature of the model is the postulated existence of two spatially disjoint near-vs. far-extra-classical regions with complementary facilitatory and suppressive contributions to the classical receptive field. The model accounts for a variety of contextual illusions, reveals commonalities between seemingly disparate phenomena, and helps organize them into a novel taxonomy. It explains how center-surround interactions may shift from attraction to repulsion in tilt effects, and from contrast to assimilation in induction phenomena. The model further explains enhanced perceptual shifts generated by a class of patterned background stimuli that activate the two opponent extra-classical regions cooperatively. Overall, the ability of the model to account for the variety and complexity of contextual illusions provides computational evidence for a novel canonical circuit that is shared across visual modalities. ER -