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The recent surge in event-related fMRI studies of episodic memory has generated a wealth of information about the neural correlates of encoding and retrieval processes. However, interpretation of individual studies is hampered by methodological differences, and by the fact that sample sizes are typically small. We submitted results from studies of episodic(More)
Previous research has established that age-related decline occurs in measures of cerebral white matter integrity, but the role of this decline in age-related cognitive changes is not clear. To conclude that white matter integrity has a mediating (causal) contribution, it is necessary to demonstrate that statistical control of the white matter-cognition(More)
Younger adults tend to remember negative information better than positive or neutral information (negativity bias). The negativity bias is reduced in aging, with older adults occasionally exhibiting superior memory for positive, as opposed to negative or neutral, information (positivity bias). Two experiments with younger (N=24 in Experiment 1, N=25 in(More)
Two experiments investigated adult age differences in episodic and semantic long-term memory tasks, as a test of the hypothesis of specific age-related decline in context memory. Older adults were slower and exhibited lower episodic accuracy than younger adults. Fits of the diffusion model (R. Ratcliff, 1978) revealed age-related increases in non-decisional(More)
Task switching requires executive control processes that undergo age-related decline. Previous neuroimaging studies have identified age-related differences in brain activation associated with global switching effects (dual-task blocks versus single-task blocks), but age-related differences in activation during local switching effects (switch trials versus(More)
Previous research suggests that, in reaction time (RT) measures of episodic memory retrieval, the unique effects of adult age are relatively small compared to the effects aging shares with more elementary abilities such as perceptual speed. Little is known, however, regarding the mechanisms of perceptual speed. We used diffusion tensor imaging (DTI) to test(More)
We combined measures from event-related functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and cognitive performance (visual search response time) to test the hypotheses that differences between younger and older adults in top-down (goal-directed) attention would be related to cortical activation, and that white matter integrity(More)
Source monitoring involves judgments regarding the origin of information (M. K. Johnson, S. Hashtroudi, & D. S. Lindsay, 1993). When participants cannot remember the source in a source-monitoring task, they may guess according to their prior schematic knowledge (U. J. Bayen, G. V. Nakamura, S. E. Dupuis, & C.-L. Yang, 2000). The present study aimed at(More)
Previous research suggests that, during visual search and discrimination tasks, older adults place greater emphasis than younger adults on top-down attention. This experiment investigated the relative contribution of target activation and distractor inhibition to this age difference. Younger and older adults performed a singleton discrimination task in(More)
Two experiments investigated adult age differences in the explicit (knowledge-based) and implicit (repetition priming) components of top-down attentional guidance during discrimination of a target singleton. Experiment 1 demonstrated an additional contribution of explicit top-down attention, relative to the implicit effect of repetition priming, which was(More)