Negative and nonemotional interference with visual working memory in schizophrenia

Abstract

Background: Schizophrenia (SCZ) results in abnormalities affecting both working memory (WM) and emotional processing. Prior work suggests that individuals with SCZ exhibit increased effects of distraction on WM-a deficit that might be exacerbated via emotional interference. However, no study characterized effects of negative and nonemotional interference on visual WM in SCZ with functional magnetic resonance imaging. We tested the hypothesis that SCZ is associated with a general inability to filter distraction versus a specific deficit in the ability to filter aversive emotional distraction.

Methods: Twenty-eight patients with DSM-IV-diagnosed SCZ and 24 matched control subjects underwent blood-oxygen-level-dependent imaging with functional magnetic resonance imaging at 3-T. Subjects performed a modified delayed-response visual WM task faced with affectively negative, neutral, or task-related interference.

Results: Control subjects showed maximal interference after aversive distraction, whereas patients were more distracted irrespective of interference type. Importantly, aversive distraction resulted in similar across-group activation in regions previously showing robust effects of negative interference. Conversely, after any distraction, patients showed reduced blood-oxygen-level-dependent activity in prefrontal regions previously implicated in filtering interference. Particularly when distracted, SCZ subjects exhibited aberrant responses to nonemotional distraction across posterior cortical regions.

Conclusions: Results suggest that patients fail to deploy activity associated with distracter filtering exhibited by control subjects. Although SCZ subjects show similar responses to aversive interference across certain regions, there is also evidence of enhanced responses to nonemotional inputs. These results are consistent with a general deficit in the ability of patients to filter distraction, which might be in line with aberrant salience processing as a pathophysiological mechanism in SCZ.