Superior parietal cortex and the attention to delayed intention: An rTMS study.

Prospective memory (PM) is the ability to remember to carry out an intention when the appropriate cue occurs. This study aimed to investigate whether the superior parietal cortex is causally involved in PM and, if so, what is its functional role. We applied repetitive transcranial magnetic stimulation (rTMS) to the left and right superior parietal cortex, and we evaluated the TMS effects on two different PM tasks that required to direct the attention towards either the external stimuli ('Monitoring-load' task) or the intention in memory ('Retrospective-load' task). rTMS of left parietal cortex produced a facilitation of PM performance in both tasks. This was coupled by slower responses to the ongoing activity, for left and right parietal stimulation, but selectively in the 'Retrospective-load' condition. The present results suggest that superior parietal cortex is causally involved in biasing top-down attentional resources between the external, ongoing stimuli and the internal, PM intentions. The possible physiological mechanisms underlying the TMS-related improvement in PM performance are discussed.