Objective: People with schizophrenia (PSZ) are impaired in the attentional prioritization of non-salient but relevant stimuli over salient but irrelevant distractors during visual working memory (VWM) encoding. Conversely, the guidance of top-down attention by external predictive cues is intact. Yet, it is unknown whether this preserved ability can help PSZ overcome impaired attentional prioritization in the presence of salient distractors.
Methods: We employed a visuospatial change-detection task using four Gabor Patches with differing orientations in 69 PSZ and 74 healthy controls (HCS). Two patches flickered to reflect saliency and either a predictive or a non-predictive cue was displayed resulting in four conditions.
Results: Across all conditions, PSZ stored significantly less information in VWM than HCS (all p < 0.001). With a non-predictive cue, PSZ stored significantly more salient than non-salient information (t140 = 5.66, p < 0.001, dt = 0.5). With a predictive cue, PSZ stored significantly more non-salient information (t140 = 5.70, p < 0.001, dt = 0.5).
Conclusion: Our findings support a bottom-up bias in schizophrenia with performance significantly better for visually salient information in the absence of a predictive cue. These results indicate that bottom-up attentional prioritization is disrupted in schizophrenia, but the top-down utilization of cues is intact. We conclude that additional top-down information significantly improves performance in PSZ when non-salient visual information needs to be encoded in working memory.
Electrophysiology reveals different mechanisms of attentional filtering during visual working memory encoding and retention
