LAUSR

&NA; Neuroimaging studies have identified multiple extra‐striate visual areas that are sensitive to symmetry in planar images (Kohler et al., 2016; Sasaki et al., 2005). Here, we investigated which of these areas are directly involved in perceptual decisions about symmetry, by recording high‐density EEG in participants (n = 25) who made rapid judgments about whether an exemplar image contained rotation symmetry or not. Stimulus‐locked sensor‐level analysis revealed symmetry‐specific activity that increased with increasing order of rotation symmetry. Response‐locked analysis identified activity occurring between 600 and 200 ms before the button‐press, that was directly related to perceptual decision making. We then used fMRI‐informed EEG source imaging to characterize the dynamics of symmetry‐specific activity within an extended network of areas in visual cortex. The most consistent cortical source of the stimulus‐locked activity was VO1, a topographically organized area in ventral visual cortex, that was highly sensitive to symmetry in a previous study (Kohler et al., 2016). Importantly, VO1 activity also contained a strong decision‐related component, suggesting that this area plays a crucial role in perceptual decisions about symmetry. Other candidate areas, such as lateral occipital cortex, had weak stimulus‐locked symmetry responses and no evidence of correlation with response timing.