Impaired visuospatial working memory but preserved attentional control in bipolar disorder.

backgroundDeficits in working memory (WM) and attention have a considerable functional impact on people with bipolar disorder (PBD). Understanding the neurocognitive underpinnings of these cognitive constructs might facilitate the discovery of more effective pro-cognitive interventions. Therefore, we employed a paradigm designed for jointly studying attentional control and WM encoding.

methodsWe used a visuospatial change-detection task using four Gabor Patches with differing orientations in 63 euthymic PBD and 76 healthy controls (HCS), which investigated attentional competition during WM encoding. To manipulate bottom-up attention using stimulus salience, two Gabor patches flickered, which were designated as either targets or distractors. To manipulate top-down attention, the Gabor patches were preceded by either a predictive or a non-predictive cue for the target locations.

resultsAcross all task conditions, PBD stored significantly less information in visual WM than HCS (significant effect of group). However, we observed no significant group-by-salience or group-by-cue interactions. This indicates that impaired WM was not caused by deficits in attentional control.

conclusionsWhile WM was disturbed in PBD, attentional prioritization of salient targets and distractors, as well as the utilization of external top-down cues, were not compromised. Thus, the control of attentional selection appears to be intact at least for our specific manipulation of this cognitive construct. These findings provide valuable clues for models of WM dysfunction in PBD by suggesting that later stages of WM encoding, such as WM consolidation, are likely primarily impaired, while selective attention is not a main source of impairment.