The extrastriate symmetry response can be elicited by flowers and landscapes as well as abstract shapes

Abstract

Previous research has investigated the neural response to visual symmetry. It is well established that symmetry activates a network of extrastriate visual regions, including V4 and the Lateral Occipital Complex. This symmetry response generates an event-related potential called the sustained posterior negativity (SPN). However, previous work has used abstract stimuli, typically dot patterns or shapes. We tested the generality of the SPN. We confirmed that the SPN wave was present and of similar amplitude for symmetrical shapes, flowers and landscapes, whether participants were responding either to image symmetry or to image color. We conclude that the extrastriate symmetry response can be generated by any two-dimensional image and is similar in different stimulus domains. We compared the neural response to symmetry in abstract shapes, flowers and landscapes. Although symmetry in landscapes is visually different, the SPN response to symmetry was similar across all three domains. This held true whether participants were actively discriminating symmetry or color. We conclude that the neural response to symmetry is both domain general and task independent.