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Paper: PS-2B.27
Session: Poster Session 2B
Location: H Fl├Ąche 1.OG
Session Time: Sunday, September 15, 17:15 - 20:15
Presentation Time:Sunday, September 15, 17:15 - 20:15
Presentation: Poster
Publication: 2019 Conference on Cognitive Computational Neuroscience, 13-16 September 2019, Berlin, Germany
Paper Title: Representational similarity analyses in simultaneous EEG-fMRI measurements reveal the spatio-temporal trajectories of reconstructed episodic memories
Manuscript:  Click here to view manuscript
License: Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 Unported License.
DOI: https://doi.org/10.32470/CCN.2019.1156-0
Authors: Julia Lifanov, Benjamin Griffiths, University of Birmingham, United Kingdom; Juan Linde-Domingo, Max Planck Institute, Germany; Catarina Ferreira, Martin Wilson, Stephen Mayhew, Ian Charest, Maria Wimber, University of Birmingham, United Kingdom
Abstract: In this project, we use multivariate analysis techniques on simultaneously acquired EEG and fMRI data to investigate the spatio-temporal dynamics of memory retrieval. We specifically explore how the neural representations of a retrieved object differ from the representations of the originally perceived object. Participants studied novel associations between objects and verbs in an encoding phase, and subsequently recalled the objects upon presentation of the corresponding verb cue. Multivariate pattern classifiers were first used to decode perceptual and conceptual processing from EEG and fMRI brain activation patterns separately. At the hemodynamic level, we found that conceptual features were generally dominant during memory retrieval, and represented at later processing stages than perceptual features. At the electrophysiological level, the conceptual dominance was reflected in an earlier representation of conceptual than perceptual information during recall, showing a reversed order relative to initial encoding (perception). Finally, representational similarity analyses allowed us to map the EEG time courses onto spatial fMRI patterns, demonstrating again that it is primarily the later stages of visual processing that are recapitulated during memory recall. Together, the results shed light onto the nature of mental representations during the reconstruction of visual objects from memory.