Modulation of a fronto-parietal network in event-based prospective memory: An rTMS study

• Published in: Neuropsychologia Vol. 49; no. 8; pp. 2225 - 2232
• Main Authors: Bisiacchi, P.S., Cona, G., Schiff, S., Basso, D.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-07-2011; Elsevier
• Subjects: Adult; Analysis of Variance; Brain; Brain Mapping; Female; Frontal Lobe - physiology; Fronto-parietal network; Functional Laterality; Humans; Intention; Intention retrieval; Male; Memory; Memory - physiology; Neural Pathways - physiology; Neurological Organization; Neuropsychological Tests; Parietal Lobe - physiology; Prospective memory; Reaction Time; rTMS; Target checking; Transcranial Magnetic Stimulation; Young Adult; Prospective memory; Intention retrieval; Target checking; rTMS; Fronto-parietal network
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2011.05.007

► Stimulation on the right dorso-lateral prefrontal cortex affects PM task. ► rTMS on the prefrontal sites affects ongoing activity only under PM task demands (not related to cue detection). ► rTMS on left parietal cortex facilitates ongoing activity and interferes with PM task. ► Early DLPFC activity is related to target checking but not to cue detection. ► Left parietal cortex is associated to retrieval of the intended action.
Event-based prospective memory (PM) is a multi-component process that requires remembering the delayed execution of an intended action in response to a pre-specified PM cue, while being actively engaged in an ongoing task. Some neuroimaging studies have suggested that both prefrontal and parietal areas are involved in the maintenance and realization of delayed intentions. In the present study, transcranial magnetic stimulation (TMS) was used to investigate the causal involvement of frontal and parietal areas in different stages of the PM process (in particular, target checking and intention retrieval), and to determine the specific contribution of these regions to PM performance.
Our results demonstrate that repetitive TMS (rTMS) interferes with prospective memory performance when applied at 150–350ms to the right dorsolateral prefrontal cortex (DLPFC), and at 400–600ms when applied to the left posterior parietal cortex (PPC).
The present study provides clear evidence that the right DLPFC plays a crucial role in early components of the PM process (target checking), while the left PPC seems to be mainly involved in later processes, such as the retrieval of the intended action.