Abstract
Despite a huge effort of the scientific community, the functioning of Long-Term Memory (LTM) processes is still debated and far from being elucidated. Functional and neurophysiological data point to an involvement of Dorsolateral Prefrontal Cortex (DLPFC) in both encoding and retrieval phases. However, the recently proposed Explicit/Implicit Memory Encoding and Retrieval (EIMER) model proposes that LTM at the encoding phase consists of anatomically and chronologically different sub-phases. On this basis, we aimed to investigate the role of right DLPFC during a late-encoding phase by means of low-frequency rTMS. Thirty right-handed healthy subjects were divided into three experimental groups. Inhibitory rTMS was applied over right-DLPFC immediately after the encoding phase (Late-Encoding Group) or before recognition phase (Pre-Recognition Group), 24 h after, of an LTM task. Both groups also received sham stimulation during the non-target phase, while the third group (Sham Group) received only sham stimulation in both phases. The Late-Encoding Group collected a lower number of correct responses compared with Sham Group (p = 0.00), while Pre-Retrieval Group increased accuracy as compared to the Sham Group (p = 0.0). rTMS-inhibition of the right DLPFC seems able to interfere with LTM memory performances when delivered at a late stage of the encoding phase, with opposite effects at the pre-retrieval phase.
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Data Availability
Data can be requested by sending a mail to dr. Luca Cuffaro (luca.cuffaro@unipa.it).
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Code can be requested by sending a mail to dr. Luca Cuffaro (luca.cuffaro@unipa.it).
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Conceptualization, TP, FA; methodology, LC, FA, FB, MG, GF, VB; software, LC; validation, GG, GG and TP; formal analysis GG and GG; investigation, GG, LC, FA, FB and MG; resources, FB, MG, PS, GF and TP; data curation, GG, GG and LC; writing—original draft preparation, GG, GG and LC; writing—review and editing, GG, GG, PS and TP; visualization, GG, GG and TP; supervision, TP; project administration, FB, MG, PS, GF and TP.
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The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of the University of Palermo.
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Giglia, G., Gambino, G., Cuffaro, L. et al. Modulating Long Term Memory at Late-Encoding Phase: An rTMS Study. Brain Topogr 34, 834–839 (2021). https://doi.org/10.1007/s10548-021-00872-y
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DOI: https://doi.org/10.1007/s10548-021-00872-y