Although numerous studies have closely examined the processes by which working memory (WM) updates and maintains information, there has been a paucity of research examining the switching mechanism between these two WM functions. O’Reilly & Frank (2006) proposed that the switching process is governed by a WM 'gate' that opens the gate to switch WM function from maintenance to updating and closes the gate to reverse the process. It is noteworthy that subsequent studies have consistently observed an asymmetry between opening and closing the WM gate. This asymmetry is manifested as a higher time cost but a lower error rate when closing the WM gate than when opening the gate. Until now, this asymmetry and the WM gating process have not been well understood. The objective of my dissertation was to elucidate the essential components of WM gating processes that determine the asymmetry between opening and closing. In particular, the roles of inhibitory control (on the state of the WM gate switches from) and intentional control (on the state the gate switches to) were investigated. A total of four studies were conducted in stages. The first study extracted the neurophysiological constituents of WM gating processes. The second study investigated the difference in effort investment between WM gate opening and closing. Another two studies further explored the causality of the asymmetry via brain stimulation methods.
All studies replicated the behavioral asymmetry between gate opening and closing (lower error rate and higher time cost for gate closing). A common neurophysiological pathway of the WM gating cascade from the ventral stream to the frontal cortex was revealed, suggesting that WM gate opening and closing follow common steps of inhibition of the previous gate state and reactivation of the required gate state. Nevertheless, the ventral stream distinguished residual preceding gate activation, whereby a stronger preceding gate state (open) remained highly activated before closing than gate-close state before opening and subsequently affected inhibitory control over it. Additionally, distinct frontal activities were observed between opening and closing, indicating a switch of attention to different sources. Strong intentional control was involved to direct the attention to sensory information during gate opening. These findings suggest that the opening of the WM gate is more effortful than the closing of the WM gate, which is perceived as more natural and effortless. It is likely that the human brain tends to maintain the WM in a closed state, and this default tendency to close the WM gate may be the origin of the asymmetry in gating performance. This knowledge sheds the light on the mechanism of WM controls and suggests a potential for predicting the developmental patterns of WM and WM deficiencies in psychiatric disorders.:PREFACE III
ACKNOLEDGEMENTS V
LIST OF FIGURES XI
LIST OF TABLES XIII
INDEX OF ABBREVATIONS XV
ABSTRACT XVII
CHAPTER 1 INTRODUCTION 1
1.1 A general introduction 3
1.2 What is the gating of WM? 4
1.3 Cognitive processes associated with WM gating 6
1.3.1 Switching-inspired view of WM gating mechanism 6
1.3.2 Inhibitory control and its potential association with gating cost in time 7
1.3.3 Intentional control and its potential association with gating accuracy 9
1.3.4 My hypothesized model of WM gating 9
1.4 Neurophysiological and anatomical associations with the WM gating process 11
1.4.1 The role of alpha band activities in the inhibition of the preceding gate 12
1.4.2 The role of theta band activities in the reconfiguration of the new WM gate 13
1.4.3 The prefrontal cortex potentially executes the WM gating 14
1.4.4 Associations between the WM gating and the frontoposterior network 15
1.5 Neurobiological underpinnings of the WM Gating 16
1.5.1 The GABAergic system and its associations with inhibitory control 16
1.5.2 The norepinephrine system and its associations with intentional control 17
CHAPTER 2 HYPOTHESES AND METHODOLOGIES 19
2.1 General hypotheses and objectives 21
2.2 Research questions and study design 22
2.2.1 The paradigm: reference-back task 22
2.2.2 Study 1: whether and how are WM gating processes constituted? 24
2.2.3 Study 2: how do individuals engage in WM gating processes? 25
2.2.4 Study 3: how does effort affect WM gating? 26
2.2.5 Study 4: what drives the difference between WM gate opening and closing? 28
CHAPTER 3 STUDIES 31
3.1 Study 1: a ventral stream-prefrontal cortex processing cascade enables WM gating dynamics 33
3.1.1 Abstract 33
3.1.2 Introduction 33
3.1.3 Results and Discussion 37
3.1.4 Methods 47
3.1.5 Competing interests 55
3.1.6 Data availability 55
3.1.7 Code availability 55
3.1.8 Acknowledgements 55
3.2 Study 2: time-on-task effects on WM gating processes—a role of theta synchronization and the norepinephrine system 55
3.2.1 Abstract 55
3.2.2 Introduction 56
3.2.3 Materials and Methods 60
3.2.4 Results 66
3.2.5 Discussion 71
3.2.6 Acknowledgements 74
3.2.7 Funding 74
3.2.8 Conflicts of Interest 75
3.2.9 Availability of data and materials 75
3.3 Study 3: atVNS specifically enhances WM gate closing mechanism 75
3.3.1 Abstract 75
3.3.2 Significance statement 76
3.3.3 Introduction 76
3.3.4 Materials and Methods 78
3.3.5 Results 92
3.3.6 Discussion 103
3.3.7 Data and code availability statement 107
3.3.8 Conflict of interest statement 107
3.3.9 Acknowledgements 107
3.4 Study 4: inhibitory control in WM gate opening: insights from alpha desynchronization and norepinephrine activity under atDCS stimulation 108
3.4.1 Abstract 108
3.4.2 Introduction 108
3.4.3 Materials and Methods 112
3.4.4 Results 121
3.4.5 Discussion 126
3.4.6 Acknowledgements 131
3.4.7 Conflicts of interest 131
3.4.8 Ethics Statement 131
3.4.9 Data and Code Availability Statement 131
CHAPTER 4 DISCUSSION 133
4.1 Summary of findings 135
4.2 The ventral stream-frontal cortex pathway of the WM gating 137
4.2.1 The ventral stream distinguishes the residual preceding gate activation 137
4.2.2 A possible hub of suppressing the preceding gate state in the parietal lobe 139
4.2.3 A cascade towards frontal cortices for reconfiguring new gate state 141
4.2.4 Distinct neural networks between opening and closing 142
4.2.5 WM gating as a switch toward external and internal information 144
4.3 Neural modulations of the WM gating process 145
4.3.1 Cognitive demands of the WM gating and NE’s modulation 145
4.3.2 The modulatory role of GABA and accompanied ABA in WM gating 148
4.4 Implications for future studies 149
4.4.1 What is the difference between WM gating and task switching? 149
4.4.2 What is the key to opening or closing the WM gate? 150
4.4.3 Is the gate-close the real default mode of the WM gate? 151
4.5 Limitations and Conclusion 153
4.5.1 Limitations 153
4.5.2 Conclusion 155
CHATPTER 5 REFERENCE 157
CHAPTER 6 APPENDEX 191
6.1 Supplementary materials for Study 1 193
6.2 Supplementary figures for Study 2 196
DECLARATION 199
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:93839 |
| Date | 27 September 2024 |
| Creators | Yu, Shijing |
| Contributors | Beste, Christian, Frings, Christian, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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