Age-related changes in antisaccade task performance: inhibitory control or working-memory engagement?

In antisaccade tasks, subjects are required to generate a saccade in the direction opposite to the location of a sudden-onset target stimulus. Compared to young adults, older adults tend to make more reflex-like eye movements towards the target, and/or show longer saccadic onset latencies on correct direct antisaccades. To better understand the nature of these effects of aging on antisaccade performance, we examined the role of age-related deficiencies in inhibitory control vis-a-vis age changes in the engagement of working memory. Inhibitory demands were manipulated using fixation-offset conditions, while working-memory demands were manipulated by varying memory-updating requirements. The results indicate that inhibitory oculomotor functions remain largely intact with advancing age; older adults' performance breaks down only when their limited working-memory capacity is taxed by increasing updating demands.