Complementary univariate and multivariate signals in the parietal cortex for visual working memory pointers and features.

An emerging body of work in visual working memory (VWM) has embraced the theoretical construct of pointers: an object is mentally represented by a content-free pointer binding the corresponding features together. In the current magnetoencephalography (MEG) study, we investigated univariate and multivariate neural responses modulated by number of objects and by number/content of features in two literature-driven posterior parietal patches: inferior and superior intraparietal sulcus (IPS). We found that, across VWM formation and maintenance, number of objects (or attended locations) is tracked by univariate signals in the inferior IPS, but by multivariate signals in the superior IPS. Feature information manifests in multivariate signals in both superior and inferior IPS across VWM formation and maintenance, and additionally in univariate signals in the inferior IPS during VWM formation. Taken together, our results suggest that complementary univariate and multivariate neural responses underlie VWM in the posterior parietal cortex.