Different states of priority recruit different neural codes in visual working memory

Abstract

We tracked the neural representation of the orientation and the location of stimuli held in working memory at different levels of priority (\"attended\" and \"unattended\" memory items -- AMI and UMI), using multivariate inverted encoding models of human fMRI. Although representation of the orientation of the AMI and of the UMI could be reconstructed in several brain regions, including in early visual and parietal regions, the identity of the UMI was actively represented in early visual cortex in a distinct \"reversed\" code, suggesting this region as a site of the focus of attention to nonspatial stimulus information. The location of stimuli was also broadly represented, although only in parietal cortex was the location of the UMI represented in a reversed code. Our results suggest that a common recoding operation may be engaged, across stimulus dimensions and brain areas, to retain information in working memory while outside the focus of attention.