Age-related deficits in rapid visuomotor decision-making

Abstract

Many goal-directed actions that require rapid visuomotor planning and perceptual decision-making are affected in older adults, causing difficulties in execution of many functional activities of daily living. Visuomotor planning and perceptual decision-making are mediated by the dorsal and ventral visual streams, respectively, but it is unclear how age-induced changes in sensory processing in these streams contribute to declines in goal-directed actions. Previously, we have shown that in healthy adults task demands affect the integration of sensory information between the two streams and more motorically demanding tasks induce earlier decisions and more decision errors. Here, we asked the question if older adults would exhibit larger declines in interactions between the two streams during demanding motor tasks. Older adults (n=15) and young controls (n=26) performed a simple reaching task and a more demanding interception task towards virtual objects. In some blocks of trials, participants also had to select an appropriate movement based on the shape of the object. Our results showed that older adults made a similar number of initial decision errors during both the reaching and interception tasks but corrected fewer of those errors during movement. During the more demanding interception decision task, older adults made more decision- and execution-related errors than young adults, which were related to early initiation of their movements. Together, these results suggest that older adults have a reduced ability to integrate new perceptual information to guide online action, which may reflect impaired ventral-dorsal stream interactions.