Affiliations: [a] Department of Psychiatry, Neurology, Psychosomatics and Psychotherapy in Childhood and Adolescence, University Medicine Rostock, Rostock, Germany | [b] Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany | [c] DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany | [d] Department of Psychiatry and Psychotherapy, University Medicine Rostock, Rostock, Germany | [e] Department of Radiology, University Medicine Rostock, Rostock, Germany
Correspondence:
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Correspondence to: Christoph Berger, University of Rostock, Department of Psychiatry, Neurology, Psychosomatics and Psychotherapy in Childhood and Adolescence, Gehlsheimer Straße 20, 18147 Rostock, Germany. Tel.: +49 381 4944637; Fax: +49 381 4944638; E-mail: christoph.berger@med.uni-rostock.de.
Abstract: Background:Research suggests generally impaired cognitive control functions in working memory (WM) processes in amnestic mild cognitive impairment (MCI) and incipient Alzheimer's disease (AD). Little is known how emotional salience of task-irrelevant stimuli may modulate cognitive control of WM performance and neurofunctional activation in MCI and AD individuals. Objective:We investigated the impact of emotional task-irrelevant visual stimuli on cortical activation during verbal WM. Methods:Twelve AD/MCI individuals and 12 age-matched healthy individuals performed a verbal WM (nback-) task with task-irrelevant emotionally neutral and emotionally negative background pictures during fMRI measurement. Results:AD/MCI individuals showed decreased WM performance compared with controls; both AD/MCI and control groups reacted slower during presentation of negative pictures, regardless of WM difficulty. The AD/MCI group showed increased activation in the left hemispheric prefrontal network, higher amygdala and less cerebellar activation with increasing WM task difficulty compared to healthy controls. Correlation analysis between neurofunctional activation and WM performance revealed a negative correlation between task sensitivity and activation in the dorsal anterior cingulum for the healthy controls but not for the AD/MCI group. Conclusion:Our data suggest compensatory activation in prefrontal cortex and amygdala, but also dysfunctional inhibition of distracting information in the AD/MCI group during higher WM task difficulty. Additionally, attentional processes affecting the correlation between WM performance and neurofunctional activation seem to be different between incipient AD and healthy aging.
