Neural oscillations associated with the primacy and recency effects of verbal working memory.

For sequential information, the first (primacy) and last (recency) items are better remembered than items in the middle of the sequence. The cognitive operations and neural correlates for the primacy and recency effects are unclear. In this paper, we investigate brain oscillations associated with these effects. MEG recordings were obtained on 19 subjects performing a modified Sternberg paradigm. Correlation analyses were performed between brain oscillatory activity and primacy and recency indices. Oscillatory activity during information maintenance, not encoding, was correlated with the primacy and recency effects. The primacy effect was associated with occipital post-desynchrony, and temporal post-synchrony. The recency effect was associated with parietal and temporal desynchrony. Differences were also observed according to the maintenance strategy. These data indicate that the primacy and recency effects are related to different neural, and likely cognitive, operations that are dependant on the strategy for information maintenance.