The Sync-Fire/deSync Model: modelling the reactivation of dynamic memories from cortical alpha oscillations

Parish, G., Michelmann, S., Hanslmayr, S. and Bowman, H. (2021) The Sync-Fire/deSync Model: modelling the reactivation of dynamic memories from cortical alpha oscillations. Neuropsychologia, 158, 107867. (doi: 10.1016/j.neuropsychologia.2021.107867) (PMID:33905757)

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Abstract

We propose a neural network model to explore how humans can learn and accurately retrieve temporal sequences, such as melodies, movies, or other dynamic content. We identify target memories by their neural oscillatory signatures, as shown in recent human episodic memory paradigms. Our model comprises three plausible components for the binding of temporal content, where each component imposes unique limitations on the encoding and representation of that content. A cortical component actively represents sequences through the disruption of an intrinsically generated alpha rhythm, where a desynchronisation marks information-rich operations as the literature predicts. A binding component converts each event into a discrete index, enabling repetitions through a sparse encoding of events. A timing component – consisting of an oscillatory “ticking clock” made up of hierarchical synfire chains – discretely indexes a moment in time. By encoding the absolute timing between discretised events, we show how one can use cortical desynchronisations to dynamically detect unique temporal signatures as they are reactivated in the brain. We validate this model by simulating a series of events where sequences are uniquely identifiable by analysing phasic information, as several recent EEG/MEG studies have shown. As such, we show how one can encode and retrieve complete episodic memories where the quality of such memories is modulated by the following: alpha gate keepers to content representation; binding limitations that induce a blink in temporal perception; and nested oscillations that provide preferential learning phases in order to temporally sequence events.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hanslmayr, Professor Simon
Creator Roles:
Hanslmayr, S.Supervision, Writing – review and editing
Authors: Parish, G., Michelmann, S., Hanslmayr, S., and Bowman, H.
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Neuropsychologia
Publisher:Elsevier
ISSN:0028-3932
ISSN (Online):1873-3514
Published Online:24 April 2021
Copyright Holders:Copyright © 2021 Elsevier
First Published:First published in Neuropsychologia 158: 107867
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
314597TIME - GLUING CROSS-MODAL MEMORIES VIA SYNCHRONISATIONSimon HanslmayrEconomic and Social Research Council (ESRC)ES/R010072/2NP - Centre for Cognitive Neuroimaging (CCNi)
313261Neural oscillations - a code for memorySimon HanslmayrEuropean Commission (EC)N/ANP - Centre for Cognitive Neuroimaging (CCNi)