The impact of age on prefrontal cortex integrity during spatial working memory retrieval.
Healthy aging is accompanied by a decline in spatial working memory that is related to functional cerebral changes within the spatial working memory network. In the last decade, important findings were presented concerning the location (e.g., prefrontal), kind (e.g., 'underactivation,' 'overactivation'), and meaning (e.g., functional deficits, compensation) of these changes. Less is known about how functional connections between specific brain regions are affected by age and how these changes are related to behavioral performance. To address these issues, we used functional magnetic resonance imaging to examine retrieval-related brain activation and functional connectivity in 18 younger individuals and 18 older individuals. We assessed working memory with a modified version of the Corsi Block-Tapping test, which requires the storage and reproduction of spatial target sequences. Analyses of group differences in brain activation and functional connectivity included comparisons between younger individuals, older individuals, older high-performers, and older low-performers. In addition, we conducted a functional connectivity analysis by using a seed region approach. In comparison to younger individuals, older individuals showed lower right-hemispheric dorsolateral prefrontal activation and lower functional connectivity between the right dorsolateral prefrontal cortex and the bilateral orbitofrontal cortex. Older high-performers showed higher right dorsolateral and anterior prefrontal cortex activation than older low-performers, as well as higher functional connectivity between these brain regions. The present results suggest age-related reductions of prefrontal activation during spatial working memory retrieval. Moreover, task-related functional connectivity appears to be lower in older adults. Performance accuracy in older adults is associated with right dorsolateral and anterior prefrontal cortex activation, and with the functional connection between these regions.
Ev. Hospital Bielefeld (EvKB), Department of Psychiatry and Psychotherapy Bethel, Research Department, Remterweg 69-71, D-33617 Bielefeld, Germany; Justus-Liebig-University of Giessen, Cognitive Neuroscience at Centre for Psychiatry (CNS@ZPG), Am Steg 28, D-35392 Giessen, Germany. Electronic address: max.toepper@evkb.de.
Max
M
Toepper
University of Bielefeld, Department of Psychology, Universitätsstraße 25, D-33615 Bielefeld, Germany.
Hans J
HJ
Markowitsch
Justus-Liebig-University of Giessen, Cognitive Neuroscience at Centre for Psychiatry (CNS@ZPG), Am Steg 28, D-35392 Giessen, Germany; Justus-Liebig-University of Giessen, Bender Institute of Neuroimaging (BION), Otto-Behaghel-Straße 10H, D-35394 Giessen, Germany.
Helge
H
Gebhardt
Ev. Hospital Bielefeld (EvKB), Department of Psychiatry and Psychotherapy Bethel, Research Department, Remterweg 69-71, D-33617 Bielefeld, Germany.
Thomas
T
Beblo
Justus-Liebig-University of Giessen, Cognitive Neuroscience at Centre for Psychiatry (CNS@ZPG), Am Steg 28, D-35392 Giessen, Germany.
Eva
E
Bauer
Mara Hospital, Bethel Epilepsy Center, Maraweg 21, D-33617 Bielefeld, Germany.
Friedrich G
FG
Woermann
Ev. Hospital Bielefeld (EvKB), Department of Psychiatry and Psychotherapy Bethel, Research Department, Remterweg 69-71, D-33617 Bielefeld, Germany.
Martin
M
Driessen
Justus-Liebig-University of Giessen, Cognitive Neuroscience at Centre for Psychiatry (CNS@ZPG), Am Steg 28, D-35392 Giessen, Germany; Justus-Liebig-University of Giessen, Bender Institute of Neuroimaging (BION), Otto-Behaghel-Straße 10H, D-35394 Giessen, Germany.
Gebhard
G
Sammer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009434:Neural Pathways; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D065852:Spatial Memory / Q000502:physiology*; D055815:Young Adult
Aging; Cognitive control; Dorsolateral prefrontal cortex; Functional connectivity; Retrieval; Working memory