Dynamics of brain activity reveal a unitary recognition signal

Abstract

Dual-process models of recognition memory typically assume that independent familiarity and recollection signals with distinct temporal profiles can each lead to recognition (enabling two routes to recognition), whereas single-process models posit a unitary "memory strength" signal. Using multivariate classifiers trained on spectral EEG features, we quantified neural evidence for recognition decisions as a function of time. Classifiers trained on a small portion of the decision period performed similarly to those also incorporating information from previous time points indicating that neural activity reflects an integrated evidence signal. We propose a single-route account of recognition memory that is compatible with contributions from familiarity and recollection signals, but relies on a unitary evidence signal that integrates all available evidence.

EEG biomarkers of free recall

“…These biomarkers, tag (+T-A+G) the process of retrieval from episodic memory. They also add to an emerging body of evidence demonstrating the utility of non-invasive methods for decoding cognitive states (Chakravarty, Chen, & Caplan, 2020; Noh, Liao, Mollison, Curran, & de Sa, 2018; Weidemann & Kahana, 2019, 2020). Given the ease of collecting non-invasive EEG data from human research subjects, and human’s potentially unique ability to spontaneously recall verbal items, the +T-A+G biomarker of episodic recall can serve as a basis for future studies that investigate the role of retrieval cues, such as the temporal, semantic and spatial contexts surrounding experienced items.…”