title: Bilateral recruitment of prefrontal cortex in working memory is associated with task demand but not with age.
abstract: Elderly adults may master challenging cognitive demands by additionally recruiting the cross-hemispheric counterparts of otherwise unilaterally engaged brain regions, a strategy that seems to be at odds with the notion of lateralized functions in cerebral cortex. We wondered whether bilateral activation might be a general coping strategy that is independent of age, task content and brain region. While using functional magnetic resonance imaging (fMRI), we pushed young and old subjects to their working memory (WM) capacity limits in verbal, spatial, and object domains. Then, we compared the fMRI signal reflecting WM maintenance between hemispheric counterparts of various task-relevant cerebral regions that are known to exhibit lateralization. Whereas language-related areas kept their lateralized activation pattern independent of age in difficult tasks, we observed bilaterality in dorsolateral and anterior prefrontal cortex across WM domains and age groups. In summary, the additional recruitment of cross-hemispheric counterparts seems to be an age-independent domain-general strategy to master cognitive challenges. This phenomenon is largely confined to prefrontal cortex, which is arguably less specialized and more flexible than other parts of the brain.
authors.affiliation: Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tuebingen, Germany m.hoellerwallscheid@gmail.com email@axel-lindner.info.
authors.forename: Melanie S
authors.initials: MS
authors.lastname: Höller-Wallscheid
authors.affiliation: Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tuebingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Thier
authors.affiliation: Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tuebingen, Germany.
authors.forename: Jörn K
authors.initials: JK
authors.lastname: Pomper
authors.affiliation: Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tuebingen, Germany m.hoellerwallscheid@gmail.com email@axel-lindner.info.
authors.forename: Axel
authors.initials: A
authors.lastname: Lindner
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: cognitive aging; lateralization; prefrontal cortex; subjective task difficulty; working memory