The influence of age and individual differences in executive function on stimulus processing in the oddball task.

Studies examining the effects of aging in the oddball task have consistently revealed an age-related change in the topography of the P3 component. Specifically, in younger adults the amplitude of this component is greatest over the parietal region of the scalp while in older adults the P3 is more evenly distributed over the parietal and frontal regions of the scalp. In the current study, Partial Least Squares (PLS) analysis was used to examine the effects of age on the full time course and topography of the event-related brain potentials (ERPs) elicited during the oddball task; and to consider the influence of individual differences in executive function on age-related differences in the oddball task. Aging and individual differences appeared to have relatively little effect on the P3b that distinguished oddball stimulus from standards. The age-related "anterior shift" in the P3 appeared to result from the stronger expression of the novelty P3 in older adults relative to younger adults, as this effect was seen for both oddball and novel stimuli relative to standard stimuli. Additionally, the effect of age interacted with variation in executive function, with the novelty P3 being elicited for novel and oddball stimuli in the low executive older adults and only for novel stimuli in the high executive older adults. These findings lead to the suggestion that the age-related anterior shift in the P3 may result from the failure of older adults with lower executive functions to habituate to the oddball stimulus. Copyright 2009 Elsevier Srl. All rights reserved.