title: The neural correlates of age effects on verbal-spatial binding in working memory.
abstract: In this study, we investigated the neural correlates of age-related differences in the binding of verbal and spatial information utilizing event-related working memory tasks. Twenty-one right handed younger adults and twenty-one right handed older adults performed two versions of a dual task of verbal and spatial working memory. In the unbound dual task version letters and locations were presented simultaneously in separate locations, while in the bound dual task version each letter was paired with a specific location. In order to identify binding-specific differences, mixed-effects ANOVAs were run with the interaction of age and task as the effect of interest. Although older adults performed worse in the bound task than younger adults, there was no significant interaction between task and age on working memory performance. However, interactions of age and task were observed in brain activity analyses. Older adults did not display the greater unbound than bound task activity that younger adults did at the encoding phase in bilateral inferior parietal lobule, right putamen, and globus pallidus as well as at the maintenance phase in the cerebellum. We conclude that the binding of letters and locations in working memory is not as efficient in older adults as it is in younger adults, possibly due to the decline of cognitive control processes that are specific to working memory binding.
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, WI 53792, USA.
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Meier
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, WI 53792, USA.
authors.forename: Veena A
authors.initials: VA
authors.lastname: Nair
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA; Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Meyerand
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA; Department of Psychiatry, University of Wisconsin, Madison, WI 53719, USA.
authors.forename: Rasmus M
authors.initials: RM
authors.lastname: Birn
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, WI 53792, USA; Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA. Electronic address: vprabhakaran@uwhealth.org.
authors.forename: Vivek
authors.initials: V
authors.lastname: Prabhakaran
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011930:Reaction Time; D065854:Spatial Navigation / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Aging; Binding; Working memory; fMRI