Neural bases of space-specific distractor biases in visual working memory

Information held in working memory (WM) is remarkably resilient to distraction. Yet, perceptual distractors that share mnemonic features can impact WM profoundly; the neural basis of this phenomenon remains unclear. With multivariate decoding of human electroencephalography recordings, we investigate how delay-period perceptual distractors bias WM. Participants memorized the orientations of cued and uncued grating memoranda that appeared in opposite hemifields. A grating distractor, flashed during the delay period, produces space-specific biases: memorized features are attracted towards or repelled away from the distractors orientation depending, respectively, on when the distractor appeared in the same hemifield as the memorandum, or opposite to it. Neural prioritization in WM by cueing, and stronger memorandum maintenance mitigate this bias, whereas stronger distractor encoding enhances it. Lastly, a ring-attractor model with cross-hemifield inhibition mechanistically explains the origins of these spatially-antagonistic biases. Our results reveal how lateralized sensory buffers critically enable perceptual distractors to bias visual WM. Lay SummaryWorking memory (WM) - the ability to momentarily store important items - is remarkably robust to distraction. Yet, when a salient object with features resembling the memorized item ("perceptual distractor") appears in the environment, it can alter WM appreciably. What neural mechanisms render WM resilient to distraction, and how can perceptual distractors affect it so profoundly? We address this question by presenting a salient distractor, at unpredictable times, during the WM delay-period. Surprisingly, the distractors bias on WM depends on its proximity to the memorandums original location. With state-of-the-art neural decoding and computational modeling, we identify mechanisms that mediate these space-specific distractor effects. The findings advance our understanding of WMs resilience to distraction and may inform cognitive therapies for treating WM deficits.