Age effects on retroactive interference during working memory maintenance

The present study uses magnetoencephalography (MEG) to examine brain magnetic patterns in young and older adults who perform an interference-based working memory (WM) task with two experimental conditions; interrupting and distracting. Behaviourally, both types of retroactive interference significantly impair WM accuracy at recognition more in older adults than in young adults with the latter exhibiting greater disruptions by interruptors. MEG results revealed the presence of differential age-related and interference-related neural patterns. Specifically, time-modulated activations in posterior-frontal regions were increased in young compared to older adults characterising each condition. Additionally, young adults exhibited greater posterior-frontal activations for the interrupting compared to the distracting condition. These results suggest that age-related deficits in inhibitory mechanisms that increase vulnerability to interference are associated with under-recruitments in posterior-frontal regions. On the other hand, the absence of differential interference-related neural recruitments reflects that both types of interference affect WM equally in the elderly.

• Retroactive interference impacts accuracy in older adults more than young adults.
• Young adults accuracy is greater disrupted by interruptors than distractors.
• Young adults show increased neural activity compared to old adults at maintenance.
• Young adults show increased neural activity for interruptors than distractors.
• Age-related under/nonselective neural recruitments may reflect inhibitory deficits.