Age Deficits In The Inhibitory Of Prepotent Responses: Evidence From Antisaccade Tasks

One task particularly amenable for studying age deficits is the antisaccade task, in which participants are required to make a saccade either toward (prosaccade) or away (antisaccade) from a flashing cue. Correct performance on antisaccade trials requires the inhibition of a prepotent response (i.e., don't look at the target) and the generation and execution of a correct saccade in the opposite direction. Researchers have found that older adults have more difficulty than younger adults when they did the antisaccade task because of inhibitory deficit of aging. This theory posit that age-related changes in cognitive abilities are caused by impaired inhibition processes. Other alternative explanations of age-related performance deficits in interference tasks have been proposed that does not require inhibition to play a role. The goal neglect theory proposes that age differences in performance on behavioral control tasks are due to a failure to maintain the current task goal in a state of activation that is sufficient to guide behavior. Age-related performance deficits may be due to older adults' response selection fail in the context of inhibition, or due to older adults' reduced working memory capacity.The current aim to demonstrate which explanation was adapt to age-related performance deficits in the antisaccade task. We selected 22 younger adults and 25 older adults. The antisaccade task was conducted to examine the age differences between younger adults and older adults by varying the arousal level (high or low) and the eccentricity (2.5°or 7.5°) in two saccade tasks (prosaccade or antisaccade). The results showed that:(1) The correct saccade latency data revealed no significant differences between younger adults and older adults in both prosaccade task and antisaccade task, which suggested that older adults had as good saccade generation as younger adults for processing speed.(2) The participants had slower correct saccade latency for the near eccentric target position compared to the far target position. Increasing the arousal level expedited both younger adults' correct saccade latency and older adults' correct saccade latency, but the expediting behaved differently in two age groups, and the younger adults expedited more in the far target position compared to did the older adults.(3) The older adults made significantly more direction errors in the antisaccade task of both high arousal level and low arousal level than did the younger adults, but the direction errors data showed no significant difference between younger adults and older adults in the prosaccade task of both high arousal level and low arousal level, which suggested that older adults had worse prepotent response inhibition. The result supports the inhibitory deficit hypothesis of aging.(4) The older adults made marginal significantly less amplitude errors in the low arousal level condition than did the younger adults, but the amplitude errors data showed no significant difference between younger adults and older adults in the high arousal level condition, which suggested that when they inhibited the prepotent response successfully, the older adults can generate as good saccade as the younger adults. The amplitude errors data further supports the inhibitory deficit hypothesis of aging.