Older adults, unlike younger adults, do not modulate alpha power to suppress irrelevant information

Abstract

This study examines the neural mechanisms through which younger and older adults ignore irrelevant information, a process that is necessary to effectively encode new memories. Some age-related memory deficits have been linked to a diminished ability to dynamically gate sensory input, resulting in problems inhibiting the processing of distracting stimuli. Whereas oscillatory power in the alpha band (8-12 Hz) over visual cortical areas is thought to dynamically gate sensory input in younger adults, it is not known whether older adults use the same mechanism to gate out sensory input. Here we identified a task in which both older and younger adults could suppress the processing of irrelevant sensory stimuli, allowing us to use electroencephalography (EEG) to explore the neural activity associated with suppression of visual processing. As expected, we found that the younger adults' suppression of visual processing was correlated with robust modulation of alpha oscillatory power. However, older adults did not modulate alpha power to suppress processing of visual information. These results demonstrate that suppression of alpha power is not necessary to inhibit the processing of distracting stimuli in older adults, suggesting the existence of alternative strategies for suppressing irrelevant, potentially distracting information.