Poster B86, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
Roles of the posterior-anterior shift and of the parietal activation maintenance in age-related protective mechanisms involved in memory
Emilie Alibran1, Badiaa Bouazzaoui1, Lucie Angel1, Marie Gomot1, Michel Isingrini1; 1University of Tours
This study compared the brain maintenance (Nyberg et al., 2012) hypothesis and the reorganization-compensation posterior-anterior shift in aging hypothesis (Davis et al., 2007) to explain age-related possible protective mechanisms involved in episodic memory. Parietal and frontal old/new effect-event-related potentials were recorded while younger and older adults performed a word stem cued-recall task. In older adults, the brain maintenance was indexed as the individual parietal old/new activation level, whereas the reorganization-compensation posterior-anterior shift was indexed by computing an old/new frontal-parietal index for each individual reflecting the relationship between frontal and parietal activation. The results confirmed that the parietal old/new effect was of larger latency, of reduced magnitude and less lateralized in the older group than in the young group. They also showed a negative age-related effect on the frontal-parietal index supporting the posterior-anterior shift hypothesis. In agreement with the reorganization-compensation hypothesis, correlation analyses indicated that the older participants who presented a high level of memory were those showing the greater posterior-anterior shift. On the other hand, in disagreement with the brain maintenance hypothesis, the individual parietal activation level was not correlated with the memory performance in older adults. Overall, these findings support the view that age-related brain reorganization through a parietal-frontal shift in neural activation is better beneficial in old age than the maintenance of a high level of parietal activation.
Topic Area: LONG-TERM MEMORY: Development & aging