Objective: Aging is accompanied by increasing difficulty in working memory (WM), the capacity to actively store and manipulate incoming information online. One hypothesis for these increasing difficulties is that they are caused by changes in the storage buffer activated during retrieval process.
Design: To test this hypothesis, 17 young (mean = 26.41 years, age range: +2.65) subjects and 17 old (mean = 71 years, age range: +9.06) subjects performed an adapted version of the n-back WM task.
Materials and Methods: We recorded event-related potentials (ERPs) associated with an Independent Component Analysis (ICA) of ERP signals. We had shown earlier that this paradigm provokes in young subjects a positive-negative (PNwm) ERP component over parietal and frontal electrodes that can represent an electrophysiological correlate of short-term maintenance-retrieval in the WM buffer.
Results: Here, we found that this PNwm component is present in both young and old subjects, indicating that the neurophysiological process of WM retrieval itself persists with age. However, both ERP and ICA measures showed age-related latency and amplitude modifications of the PNwm component with increasing WM load, as well as topographical changes over frontal electrodes.
Conclusion: These changes suggest that age-related difficulties in WM might reflect decreasing precision in the temporal processing of maintenance-retrieval processes, presumably over anterior areas.
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