title: Aging: compensation or maturation?
abstract: Neuroimaging studies of healthy aging often reveal differences in neural activation patterns between young and elderly groups for episodic memory tasks, even though there are no differences in behavioral performance. One explanation typically offered is that the elderly compensate for their memory deficiencies through the recruitment of additional prefrontal regions. The present study of healthy aging compared magnetoencephalographic (MEG) time-courses localized to specific cortical regions in two groups of subjects (20-29 years and >or=65 years) during a visual delayed-match-to-sample (DMS) task. MR morphometrics and neuropsychological test results were also examined with the hope of providing insight into the nature of the age-related differences. The behavioral results indicated no differences in performance between young and elderly groups. Although there was a main effect of age on the latency of the initial peak in primary/secondary visual cortex, these longer latencies were not correlated with the performance of elderly on the DMS task. The lateral occipital gyrus (LOG) revealed qualitatively different patterns of activity for the two age groups corroborated by neuropsychological test results. Morphometric results for the young versus elderly groups revealed less white (WM) and gray matter (GM) volumes in the frontal lobes of the elderly. When a group of middle-aged subjects (33-43 years) was included in the morphometric analyses, the middle-aged subjects revealed statistically greater WM volumes in frontal and parietal cortex suggesting immature WM tracts in the young. Perhaps our elderly utilized a different strategy compared to the young due to the different brain maturation levels of these groups.
authors.affiliation: Research, New Mexico VA Health Care Systems, and Department of Radiology, UNM School of Medicine, Albuquerque, NM 87108, USA. aine@unm.edu
authors.forename: Cheryl J
authors.initials: CJ
authors.lastname: Aine
authors.forename: Chad C
authors.initials: CC
authors.lastname: Woodruff
authors.forename: Janice E
authors.initials: JE
authors.lastname: Knoefel
authors.forename: John C
authors.initials: JC
authors.lastname: Adair
authors.forename: David
authors.initials: D
authors.lastname: Hudson
authors.forename: Clifford
authors.initials: C
authors.lastname: Qualls
authors.forename: Jeremy
authors.initials: J
authors.lastname: Bockholt
authors.forename: Elaine
authors.initials: E
authors.lastname: Best
authors.forename: Sanja
authors.initials: S
authors.lastname: Kovacevic
authors.forename: Wayne
authors.initials: W
authors.lastname: Cobb
authors.forename: Denise
authors.initials: D
authors.lastname: Padilla
authors.forename: Blaine
authors.initials: B
authors.lastname: Hart
authors.forename: Julia M
authors.initials: JM
authors.lastname: Stephen
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development* / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D013702:Temporal Lobe / Q000502:physiology