title: Characterising neural signatures of successful aging: Electrophysiological correlates of preserved episodic memory in older age.
abstract: While aging is associated with a gradual decline in memory, substantial preservation of function is observed in certain individuals and dissecting this heterogeneity is paramount to understanding successful aging. A cohort of elderly individuals were classified according to their level of memory preservation and administered a test of episodic memory in which participants were cued to learn or simply read each word and then to identify previously presented items in a delayed recognition phase. Mathematical modelling revealed that relatively preserved memory function was specifically linked to a faster rate of memorial evidence accumulation (drift rate). Analysis of event-related potentials at encoding revealed that high-performing elderly exhibited signals over parietal regions that discriminated between words to be learned vs. read for an additional 300-ms compared to young subjects suggesting a compensatory encoding mechanism that was absent in the low-performing group. At recognition, parietal signals associated with recollection processes discriminated previously learned words from read words in the young and high-performing old but not in low-performing old. These results reveal that successful aging is associated with specific adaptive neural markers during both encoding and retrieval.
authors.affiliation: Trinity College Institute of Neuroscience & School of Psychology, Trinity College, Dublin, Ireland. Electronic address: DOCKREEP@tcd.ie.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Dockree
authors.affiliation: Trinity College Institute of Neuroscience & School of Psychology, Trinity College, Dublin, Ireland.
authors.forename: Sabina
authors.initials: S
authors.lastname: Brennan
authors.affiliation: Trinity College Institute of Neuroscience & School of Psychology, Trinity College, Dublin, Ireland.
authors.forename: Michael
authors.initials: M
authors.lastname: O'Sullivan
authors.affiliation: Trinity College Institute of Neuroscience & School of Psychology, Trinity College, Dublin, Ireland.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Robertson
authors.affiliation: Trinity College Institute of Neuroscience & School of Psychology, Trinity College, Dublin, Ireland.
authors.forename: Redmond G
authors.initials: RG
authors.lastname: O'Connell
mesh_terms: D000293:Adolescent; D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D061212:Memory, Episodic; D010296:Parietal Lobe / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D011932:Reading; D014706:Verbal Learning / Q000502:physiology*; D055815:Young Adult
keywords: Encoding; Episodic memory; Event-related potentials; Neural compensation; Recognition; Successful aging