The relationship between maintenance and manipulation components of working memory and prefrontal and parietal brain regions in bipolar disorder

• Published in: Journal of affective disorders Vol. 264; pp. 519 - 526
• Main Authors: Cho, Ivy Y.K., Goghari, Vina M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2020
• Subjects: Bipolar disorder; Bipolar Disorder - diagnostic imaging; Brain; Humans; Magnetic Resonance Imaging; Maintenance; Manipulation; Memory, Short-Term; Neuropsychological Tests; Parietal Lobe - diagnostic imaging; Prefrontal Cortex - diagnostic imaging; Structural neuroimaging; Visuospatial working memory; Bipolar disorder; Visuospatial working memory; Maintenance; Manipulation; Structural neuroimaging
• ISSN: 0165-0327; 1573-2517
• DOI: 10.1016/j.jad.2019.11.085

•Bipolar patients showed an overall decrease on the working memory task accuracy, but did not show a greater deficit in manipulation compared to controls.•Patients had thinner cortices in prefrontal and parietal regions, regions that are associated with working memory.•Better maintenance accuracy had a small association with thicker prefrontal cortices in bipolar patients. A domain of cognition that has been found to be impaired in bipolar disorder across mood states is working memory. Working memory can be separated into two components, maintenance and manipulation. Bipolar patients also demonstrate structural brain abnormalities in prefrontal and parietal regions, which are regions associated with working memory processes. Despite the understanding that working memory consists of multiple separable cognitive processes, no study to date has differentiated maintenance and manipulation, and associated them with underlying structural brain regions in bipolar disorder. Twenty-six bipolar patients and 24 controls completed a visuospatial working memory task and structural neuroimaging. Prefrontal and parietal gray matter volume, surface area, and cortical thickness were obtained using FreeSurfer. The relationship between working memory performance, structural integrity, symptoms, and functioning were investigated. Bipolar patients were less accurate on the working memory task compared to controls, without a greater deficit in the manipulation condition. Controls had thicker prefrontal and parietal cortices than bipolar patients. In bipolar patients, thicker prefrontal cortices had a small association with greater accuracy on the maintenance condition, as well as greater depression. This study could have benefitted from a larger sample size. Bipolar patients demonstrated both poorer accuracy on the visuospatial working memory task compared to controls and thinner cortices in areas associated with working memory, namely the prefrontal and parietal cortices. This demonstrates an underlying relationship between brain and behavior in bipolar disorder.