Abstract
Previous studies have shown that the content of visual working memory (VWM) can be decoded in both human early visual cortex (EVC) and posterior parietal cortex (PPC). At the same time, task-irrelevant distractors shown during the VWM delay period can also be decoded in these brain regions. This study examined how targets and distractors may be represented together in EVC and PPC in a VWM task. In each trial of the study, participants retained a target object while viewing a stream of distractor objects during the VWM delay period. The target and distractor objects came from the same four object categories, allowing exemplars from the same object category to serve as targets or distractors in different trials. This enabled the testing of how the object representational space in a VWM task may be jointly shaped by targets and distractors with the same set of objects. Results from 12 participants showed that while the overall object representational structure during VWM delay was dominated by distractors in EVC, it was shaped by both targets and distractors in PPC. Thus, target representation plays a more prominent role in PPC than EVC in determining the object representational space during VWM delay period. Additional analysis showed that target decoding could be found both within the same distractor category and across different distractor categories in both EVC and PPC. This suggests that targets and distractors are represented in a largely independent, rather than entangled, manner. Together, these results characterize how targets and distractors may be represented together in VWM in human EVC and PPC.