Multiple traces and altered signal-to-noise in systems consolidation: Evidence from the 7T fMRI Natural Scenes Dataset

Thomas J. Vanasse, Melanie Boly, Emily J Allen, Yihan Wu, Thomas Naselaris, Kendrick Kay, Chiara Cirelli, Giulio Tononi

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The brain mechanisms of memory consolidation remain elusive. Here, we examine blood-oxygen-level-dependent (BOLD) correlates of image recognition through the scope of multiple influential systems consolidation theories. We utilize the longitudinal Natural Scenes Dataset, a 7-Tesla functional magnetic resonance imaging human study in which ∼135,000 trials of image recognition were conducted over the span of a year among eight subjects. We find that early- and late-stage image recognition associates with both medial temporal lobe (MTL) and visual cortex when evaluating regional activations and a multivariate classifier. Supporting multiple-trace theory (MTT), parts of the MTL activation time course show remarkable fit to a 20-y-old MTT time-dynamical model predicting early trace intensity increases and slight subsequent interference (R2 > 0.90). These findings contrast a simplistic, yet common, view that memory traces are transferred from MTL to cortex. Next, we test the hypothesis that the MTL trace signature of memory consolidation should also reflect synaptic “desaturation,” as evidenced by an increased signal-to-noise ratio. We find that the magnitude of relative BOLD enhancement among surviving memories is positively linked to the rate of removal (i.e., forgetting) of competing traces. Moreover, an image-feature and time interaction of MTL and visual cortex functional connectivity suggests that consolidation mechanisms improve the specificity of a distributed trace. These neurobiological effects do not replicate on a shorter timescale (within a session), implicating a prolonged, offline process. While recognition can potentially involve cognitive processes outside of memory retrieval (e.g., re-encoding), our work largely favors MTT and desaturation as perhaps complementary consolidative memory mechanisms.

Original languageEnglish (US)
Article numbere2123426119
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Nov 1 2022

Bibliographical note

Funding Information:
ACKNOWLEDGMENTS. Research reported in this publication was supported by the National Institute of Neurological Disorders and Stroke of the NIH under Award F32NS114034. Collection of the NSD was supported by NSF IIS-1822683 (K.K.) and NSF IIS-1822929 (T.N.). G.T., C.C., and M.B. are supported by a grant from the Tiny Blue Dot Foundation and the Department of Defense (G.T. and C.C., W911NF1910280). The content herein is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations.

Publisher Copyright:
Copyright © 2022 the Author(s). Published by PNAS.


  • fMRI
  • memory consolidation
  • multiple-trace theory

Center for Magnetic Resonance Research (CMRR) tags

  • BFC

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.


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