title: Trying to Put the Puzzle Together: Age and Performance Level Modulate the Neural Response to Increasing Task Load within Left Rostral Prefrontal Cortex.
abstract: Age-related working memory decline is associated with functional cerebral changes within prefrontal cortex (PFC). Kind and meaning of these changes are heavily discussed since they depend on performance level and task load. Hence, we investigated the effects of age, performance level, and load on spatial working memory retrieval-related brain activation in different subregions of the PFC. 19 younger (Y) and 21 older (O) adults who were further subdivided into high performers (HP) and low performers (LP) performed a modified version of the Corsi Block-Tapping test during fMRI. Brain data was analyzed by a 4 (groups: YHP, OHP, YLP, and OLP) × 3 (load levels: loads 4, 5, and 6) ANOVA. Results revealed significant group × load interaction effects within rostral dorsolateral and ventrolateral PFC. YHP showed a flexible neural upregulation with increasing load, whereas YLP reached a resource ceiling at a moderate load level. OHP showed a similar (though less intense) pattern as YHP and may have compensated age-effects at high task load. OLP showed neural inefficiency at low and no upregulation at higher load. Our findings highlight the relevance of age and performance level for load-dependent activation within rostral PFC. Results are discussed in the context of the compensation-related utilization of neural circuits hypothesis (CRUNCH) and functional PFC organization.
authors.affiliation: Cognitive Neuroscience at the Centre for Psychiatry, University of Giessen, Am Steg 24, 35385 Giessen, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Bauer
authors.affiliation: Cognitive Neuroscience at the Centre for Psychiatry, University of Giessen, Am Steg 24, 35385 Giessen, Germany ; Department of Psychology, University of Giessen, Otto-Behaghel-Straße 10, 35394 Giessen, Germany ; Bender Institute of Neuroimaging, University of Giessen, Otto-Behaghel-Straße 10H, 35394 Giessen, Germany.
authors.forename: Gebhard
authors.initials: G
authors.lastname: Sammer
authors.affiliation: Evangelic Hospital Bielefeld (EvKB), Department of Psychiatry and Psychotherapy Bethel, Research Department, Remterweg 69-71, 33617 Bielefeld, Germany ; Evangelic Hospital Bielefeld (EvKB), Department of Psychiatry and Psychotherapy Bethel, Department of Geriatric Psychiatry, Bethesdaweg 12, 33617 Bielefeld, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Toepper
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D013647:Task Performance and Analysis; D055815:Young Adult