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Temporal Dynamics of Memory Integration Processes

Liu, Zhenghao LU (2025)
Abstract
Episodic memories can extend beyond direct experiences. For example, if you see a woman walking a dog and later observe a man walking the same dog, you might infer a connection between them. These inferences, crucial for making novel decisions and extending knowledge to new situations, are thought to rely on memory integration mechanisms.
Two main mechanisms have been proposed for memory integration. The integrative encoding account suggests that novel experiences can trigger the reactivation of past events, promoting the incorporation of new information into existing knowledge structures to form integrated memory representations. A complementary view proposes that memory integration can be achieved on demand, by flexibly retrieving... (More)
Episodic memories can extend beyond direct experiences. For example, if you see a woman walking a dog and later observe a man walking the same dog, you might infer a connection between them. These inferences, crucial for making novel decisions and extending knowledge to new situations, are thought to rely on memory integration mechanisms.
Two main mechanisms have been proposed for memory integration. The integrative encoding account suggests that novel experiences can trigger the reactivation of past events, promoting the incorporation of new information into existing knowledge structures to form integrated memory representations. A complementary view proposes that memory integration can be achieved on demand, by flexibly retrieving and recombining information from distinct memory representations.
The present thesis employs time-resolved multivariate pattern analysis and representational similarity analysis to measure memory reactivation during new learning and tests of associative inference. This approach enables the investigation of the temporal dynamics of processes underlying memory integration and their boundary conditions. Study 1 investigates the temporal dynamics of integrative encoding and highlights individual differences in the capacity to integrate memories across events. Study 2 examines how the encoding context influences memory integration processes, while Study 3 focuses on the distinct roles of context and semantic schema in memory integration. Finally, Study 4 investigates how both integrated and separate memory representations support episodic memory.
This thesis presents novel evidence on the mechanisms underlying memory integration and elucidates potential boundary conditions for integrating memories across different events. In conclusion, memory integration is a multifaceted phenomenon influenced by processes at multiple mnemonic stages and by various boundary conditions. The resulting integrated and separate representations are adaptively used to support goal-relevant behaviour, highlighting the flexibility and complexity of memory functions. (Less)
Abstract (Swedish)
Episodiska minnen kan sträcka sig bortom direkta upplevelser. Till exempel, om du ser en kvinna promenera med en hund och senare observerar en man med samma hund, kan du dra slutsatsen att det finns en koppling mellan dem. Sådana inferenser är centrala för att möjliggöra flexibelt beslutsfattande och generalisering av tidigare kunskap till nya situationer, och anses bero på mekanismer för minnesintegration.
Två huvudsakliga mekanismer har föreslagits för hur minnesintegration sker. Enligt teorin om integrativ inkodning kan nya erfarenheter utlösa reaktivering av tidigare relaterade händelser, vilket främjar införlivandet av ny information i befintliga kunskapsstrukturer och därmed bildandet av integrerade minnesrepresentationer. En... (More)
Episodiska minnen kan sträcka sig bortom direkta upplevelser. Till exempel, om du ser en kvinna promenera med en hund och senare observerar en man med samma hund, kan du dra slutsatsen att det finns en koppling mellan dem. Sådana inferenser är centrala för att möjliggöra flexibelt beslutsfattande och generalisering av tidigare kunskap till nya situationer, och anses bero på mekanismer för minnesintegration.
Två huvudsakliga mekanismer har föreslagits för hur minnesintegration sker. Enligt teorin om integrativ inkodning kan nya erfarenheter utlösa reaktivering av tidigare relaterade händelser, vilket främjar införlivandet av ny information i befintliga kunskapsstrukturer och därmed bildandet av integrerade minnesrepresentationer. En alternativ teori föreslår att integration kan ske vid behov, genom flexibel återhämtning och rekombination av information från separata minnesspår.
Denna avhandling använder tidsupplöst multivariat mönsteranalys samt representationslikhetsanalys för att mäta minnesreaktivering under ny inlärning och vid tester av associativ inferens. Denna ansats möjliggör undersökning av den temporala dynamiken i processer som ligger till grund för minnesintegration och deras gränsvillkor. Denna ansats möjliggör en undersökning av de temporala dynamiker som präglar minnesintegration, liksom identifiering av dess gränsvillkor. Studie 1 undersöker den temporala dynamiken i integrativ inkodning och belyser individuella skillnader i förmågan att integrera minnen över olika händelser. Studie 2 analyserar hur inkodningskontexten påverkar integrationsprocesserna, medan Studie 3 fokuserar på de distinkta roller som kontext respektive semantiska scheman spelar i dessa. Slutligen utforskar Studie 4 hur både integrerade och separata minnesrepresentationer bidrar till episodiskt minne.
Avhandlingen presenterar ny empirisk evidens för de mekanismer som ligger till grund för minnesintegration, samt klargör möjliga gränsvillkor för integration av minnen över skilda händelser. Sammanfattningsvis framstår minnesintegration som ett mångfacetterat fenomen, påverkat av processer i flera minnesstadier och av olika gränsvillkor. De resulterande integrerade och separata representationerna används adaptivt för att stödja målorienterat beteende, vilket understryker minnesfunktionernas flexibilitet och komplexitet. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Staresina, Bernhard, Oxford University
organization
publishing date
type
Thesis
publication status
published
subject
keywords
memory integration, EEG, MVPA, RSA, context, schema
pages
68 pages
publisher
Lund University
defense location
Eden’s auditorium, Allhelgona kyrkogata 14, Lund
defense date
2025-06-03 13:15:00
ISBN
978-91-8104-541-3
978-91-8104-542-0
language
English
LU publication?
yes
id
fbfb33aa-5dc7-4e43-951b-9d29018198ea
date added to LUP
2025-05-07 16:38:50
date last changed
2025-05-13 07:26:20
@phdthesis{fbfb33aa-5dc7-4e43-951b-9d29018198ea,
  abstract     = {{Episodic memories can extend beyond direct experiences. For example, if you see a woman walking a dog and later observe a man walking the same dog, you might infer a connection between them. These inferences, crucial for making novel decisions and extending knowledge to new situations, are thought to rely on memory integration mechanisms.<br/>Two main mechanisms have been proposed for memory integration. The integrative encoding account suggests that novel experiences can trigger the reactivation of past events, promoting the incorporation of new information into existing knowledge structures to form integrated memory representations. A complementary view proposes that memory integration can be achieved on demand, by flexibly retrieving and recombining information from distinct memory representations.<br/>The present thesis employs time-resolved multivariate pattern analysis and representational similarity analysis to measure memory reactivation during new learning and tests of associative inference. This approach enables the investigation of the temporal dynamics of processes underlying memory integration and their boundary conditions. Study 1 investigates the temporal dynamics of integrative encoding and highlights individual differences in the capacity to integrate memories across events. Study 2 examines how the encoding context influences memory integration processes, while Study 3 focuses on the distinct roles of context and semantic schema in memory integration. Finally, Study 4 investigates how both integrated and separate memory representations support episodic memory.<br/>This thesis presents novel evidence on the mechanisms underlying memory integration and elucidates potential boundary conditions for integrating memories across different events. In conclusion, memory integration is a multifaceted phenomenon influenced by processes at multiple mnemonic stages and by various boundary conditions. The resulting integrated and separate representations are adaptively used to support goal-relevant behaviour, highlighting the flexibility and complexity of memory functions.}},
  author       = {{Liu, Zhenghao}},
  isbn         = {{978-91-8104-541-3}},
  keywords     = {{memory integration; EEG; MVPA; RSA; context; schema}},
  language     = {{eng}},
  publisher    = {{Lund University}},
  school       = {{Lund University}},
  title        = {{Temporal Dynamics of Memory Integration Processes}},
  url          = {{https://lup.lub.lu.se/search/files/218699934/e-nailing_ex_zheng.pdf}},
  year         = {{2025}},
}