Late positive complex in event-related potentials tracks memory signals when they are decision relevant.

Authors

Haopei Yang
Geoffrey Laforge
Bobby Stojanoski
Emily S Nichols
Ken McRae
Stefan Köhler

Document Type

Article

Publication Date

7-1-2019

Journal

Sci Rep

Volume

9

Issue

1

First Page

9469

Last Page

9469

URL with Digital Object Identifier

https://doi.org/10.1038/s41598-019-45880-y

Abstract

The Late Positive Complex (LPC) is an Event-Related Potential (ERP) consistently observed in recognition-memory paradigms. In the present study, we investigated whether the LPC tracks the strength of multiple types of memory signals, and whether it does so in a decision dependent manner. For this purpose, we employed judgements of cumulative lifetime exposure to object concepts, and judgements of cumulative recent exposure (i.e., frequency judgements) in a study-test paradigm. A comparison of ERP signatures in relation to degree of prior exposure across the two memory tasks and the study phase revealed that the LPC tracks both types of memory signals, but only when they are relevant to the decision at hand. Another ERP component previously implicated in recognition memory, the FN400, showed a distinct pattern of activity across conditions that differed from the LPC; it tracked only recent exposure in a decision-dependent manner. Another similar ERP component typically linked to conceptual processing in past work, the N400, was sensitive to degree of recent and lifetime exposure, but it did not track them in a decision dependent manner. Finally, source localization analyses pointed to a potential source of the LPC in left ventral lateral parietal cortex, which also showed the decision-dependent effect. The current findings highlight the role of decision making in ERP markers of prior exposure in tasks other than those typically used in studies of recognition memory, and provides an initial link between the LPC and the previously suggested role of ventral lateral parietal cortex in memory judgements.

Notes

This article was initially published by Springer Nature Limited in Scientific Reports. Open access is provided at: https://doi.org/10.1038/s41598-019-45880-y

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