Poster C90, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Age-related differences in time course of brain activation and connectivity during feedback-based associative learning.
Sandra CHANRAUD1,2, Georges DI-SCALA1, Maud DUPUY1, Bixente DILHARREGUY1, Michèle ALLARD1,2,3; 1INCIA - Université de Bordeaux, UMR 5287- CNRS, Bordeaux cedex, France, 2EPHE, PSL Research University, Bordeaux, France, 3CHU de Bordeaux, Bordeaux, France
In young subjects, first-order rules learning is accompanied by decreased cerebellar activity as responses become automatic. In aging, both automatization abilities and cerebellar integrity are questioned. Here, we aimed at investigating cerebellar time-locked activity during automatization of a learning task in aging. Older (OS, n=15, 60-70 years old) and younger (YS, n=15, 20-30 years old) adults were included and performed on an associative learning task, involving trial and error discovery of the correspondence between figures and responses keys. There was two reinforcement levels: High learning (HL; 100% of feedback) and Low Learning (LL; 50 % of feedback), for different rates of automatization. Imaging data were collected using a 3.0 Tesla Philips Achieva scanner and, preprocessed and analyzed with SPM8 in a group x time x conditions interaction, in a parametric F-design including time and dispersion derivatives. A PPI analysis was conducted with 2 different time windows of the task as specific conditions. The performance of OS progressed slowly but reached at the end, a level comparable to that of YS at the beginning of the task. Different time-related activations were revealed between-groups in the cerebellum lobule VI and in the hippocampus. By the end of the task, the effective connectivity in OS in comparison to YS was higher between the cerebellum and the cingulate cortex and lower between the cerebellum and the hippocampus. Activation results might reflect neural decrements related to cognitive slowing; and difficulty to maintaining cerebello-hippocampal connectivity while performing on the task may induce inefficient encoding of stimuli.
Topic Area: LONG-TERM MEMORY: Development & aging