scholarly journals Electrophysiological studies of identifying and modulating the preparatory strategic processes involved in episodic memory retrieval

2018 ◽  
Author(s):  
◽  
Mason H. Price
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Task Demands ◽  
Event Related Potential ◽  
Oscillatory Activity ◽  
Retrieval Task ◽  
Retrieval Cues ◽  
Starting Point ◽  
Episodic Memories ◽  
Cue Processing

Successful retrieval of episodic memories has been shown to depend on the overlap between the processes engaged during encoding and those re-engaged during retrieval. The ability to strategically adapt cue processing to maximize this overlap, sometimes referred to as “retrieval orientation”, has been supported by numerous studies employing electroencephalography (EEG), which demonstrate differences according to the class of memories being sought. However, research in this domain has largely focused on event-related potential (ERP) effects of sustained amplitude that occur after the onset of retrieval cues, thereby failing to indicate whether such effects might be engaged in a preparatory manner before cue onset. Here, we describe two experiments that addressed this issue by employing an analysis approach focusing on the pre-stimulus period of retrieval test trials and capitalizing on the increased sensitivity of multivariate pattern analysis (MVPA) of oscillatory activity. Experiment 1 established evidence of a preparatory form of retrieval orienting and examined the potential fluctuation versus stability of such processing. Experiment 2 attempted to directly modulate the engagement of orienting processes by parametrically manipulating the extent to which responses during the retrieval task are speeded. By novelly quantifying the relationship between multivariate neural correlates of retrieval orientation and behavioral measures of performance, and testing how orienting might be flexibly adjusted to meet task demands, the current project serves as a starting point for developing techniques aimed at improving episodic memory retrieval through strategic control.

Going Their Separate Ways: Dissociation of Hippocampal and Dorsolateral Prefrontal Activation during Episodic Retrieval and Post-retrieval Processing

2010 ◽  
Vol 22 (3) ◽  
pp. 513-525 ◽  
Author(s):  
Sarah L. Israel ◽  
Tyler M. Seibert ◽  
Michelle L. Black ◽  
James B. Brewer
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Relative Increase ◽  
Network Activity ◽  
Default Network ◽  
Episodic Retrieval ◽  
Retrieval Task ◽  
Paired Associates ◽  
Hippocampal Activity ◽  
Dorsolateral Prefrontal

Hippocampal activity is modulated during episodic memory retrieval. Most consistently, a relative increase in activity during confident retrieval is observed. Dorsolateral prefrontal cortex (DLPFC) is also activated during retrieval, but may be more generally activated during cognitive-control processes. The “default network,” regions activated during rest or internally focused tasks, includes the hippocampus, but not DLPFC. Therefore, DLPFC and the hippocampus should diverge during difficult tasks suppressing the default network. It is unclear, however, whether a difficult episodic memory retrieval task would suppress the default network due to difficulty or activate it due to internally directed attention. We hypothesized that a task requiring episodic retrieval followed by rumination on the retrieved item would increase DLPFC activity, but paradoxically reduce hippocampal activity due to concomitant suppression of the default network. In the present study, blocked and event-related fMRI were used to examine hippocampal activity during episodic memory recollection and postretrieval processing of paired associates. Subjects were asked to make living/nonliving judgments about items visually presented (classify) or items retrieved from memory (recall–classify). Active and passive baselines were used to differentiate task-related activity from default-network activity. During the “recall–classify” task, anterior hippocampal activity was selectively reduced relative to “classify” and baseline tasks, and this activity was inversely correlated with DLPFC. Reaction time was positively correlated with DLPFC activation and default-network/hippocampal suppression. The findings demonstrate that frontal and hippocampal activity are dissociated during difficult episodic retrieval tasks and reveal important considerations for interpreting hippocampal activity associated with successful episodic retrieval.

scholarly journals Increases in Theta Oscillatory Activity During Episodic Memory Retrieval Following Mindfulness Meditation Training

2019 ◽  
Vol 13 ◽  
Author(s):  
Erika Nyhus ◽  
William Andrew Engel ◽  
Tomas Donatelli Pitfield ◽  
Isabella Marie Wang Vakkur
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Mindfulness Meditation ◽  
Oscillatory Activity

scholarly journals Increased task-dependent functional connectivity by stimulation of the hippocampal network predicts memory enhancement

2019 ◽  
Author(s):  
Kristen N. Warren ◽  
Molly S. Hermiller ◽  
Aneesha S. Nilakantan ◽  
Joel L. Voss
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Network Connectivity ◽  
Network Control ◽  
Retrieval Task ◽  
Memory Processing ◽  
Hippocampal Network ◽  
Hippocampal Networks

AbstractSuccessful episodic memory involves dynamic increases in the coordination of activity across distributed hippocampal networks, including the posterior-medial network (PMN) and the anterior-temporal network (ATN). We tested whether this up-regulation of functional connectivity during memory processing can be enhanced within hippocampal networks by noninvasive stimulation, and whether such task-dependent connectivity enhancement predicts episodic memory improvement. Participants received stimulation targeting either the PMN or an out-of-network control location. We compared the effects of stimulation on fMRI connectivity measured during an autobiographical memory retrieval task versus during rest within the PMN and the ATN. PMN-targeted stimulation significantly increased connectivity during memory retrieval versus rest within the PMN. This effect was not observed in the ATN, or in either network due to control out-of-network stimulation. Task-dependent increases in connectivity due to PMN-targeted stimulation within the medial temporal lobe predicted improved performance of a separate episodic memory test. It is therefore possible to enhance the task-dependent regulation of hippocampal network connectivity that supports memory processing using noninvasive stimulation.

scholarly journals Event-related Potential Evidence that Automatic Recollection Can Be Voluntarily Avoided

2009 ◽  
Vol 21 (7) ◽  
pp. 1280-1301 ◽  
Author(s):  
Zara M. Bergström ◽  
Jan de Fockert ◽  
Alan Richardson-Klavehn
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Event Related Potential ◽  
Voluntary Control ◽  
Attentional Processes ◽  
Control Processes ◽  
Conscious Recollection

Voluntary control processes can be recruited to facilitate recollection in situations where a retrieval cue fails to automatically bring to mind a desired episodic memory. We investigated whether voluntary control processes can also stop recollection of unwanted memories that would otherwise have been automatically recollected. Participants were trained on cue–associate word-pairs, then repeatedly presented with the cue and asked to either recollect or avoid recollecting the associate, while having the event-related potential (ERP) correlate of conscious recollection measured. Halfway through the phase, some cues switched instructions so that participants had to start avoiding recall of associates they had previously repeatedly recalled, and vice versa. ERPs during recollection avoidance showed a significantly reduced positivity in the correlate of conscious recollection, and switching instructions reversed the ERP effect even for items that had been previously repeatedly recalled, suggesting that voluntary control processes can override highly practiced, automatic recollection. Avoiding recollection of particularly prepotent memories was associated with an additional, earlier ERP negativity that was separable from the later voluntary modulation of conscious recollection. The findings have implications for theories of memory retrieval by highlighting the involvement of voluntary attentional processes in controlling conscious recollection.

scholarly journals Effects of Age on the Neural Correlates of Retrieval Cue Processing are Modulated by Task Demands

2009 ◽  
Vol 21 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Sandrine Duverne ◽  
Shahab Motamedinia ◽  
Michael D. Rugg
Keyword(s):  
Recognition Task ◽  
Event Related Potentials ◽  
Retrieval Task ◽  
Retrieval Cues ◽  
Test Items ◽  
Study Material ◽  
Related Potentials ◽  
Study Test ◽  
Young Subjects ◽  
Cue Processing

The electrophysiological correlates of retrieval orientation—the differential processing of retrieval cues according to the nature of the sought-for information—were investigated in healthy young (18–20 years old) and older (63–77 years old) adults. In one pair of study–test cycles, subjects studied either words or pictures presented in one of two visually distinct contexts, and then performed a yes/no recognition task with words as test items. In another pair of study–test cycles, subjects again made recognition judgments, but were required, in addition, to signal the study context for each item judged “old.” Young subjects' event-related potentials (ERPs) for new (unstudied) test items were more negative-going when the study material was pictures rather than words, and this effect varied little between the two retrieval tasks. Replicating a previous report [Morcom, A. M., & Rugg, M. D. Effects of age on retrieval cue processing as revealed by ERPs. Neuropsychologia, 42, 1525–1542, 2004], the effects of study material on the ERPs of the older subjects were attenuated and statistically nonsignificant in the recognition task. In the source retrieval task, however, material effects in the older group were comparable in both onset latency and magnitude with those of the young subjects. Thus, the failure of older adults to demonstrate differential cue processing in tests of recognition memory likely reflects the adoption of a specific retrieval strategy rather than the incapacity to process retrieval cues in a goal-directed manner.

Expertise, attention, and memory in sensorimotor skill execution: Impact of novel task constraints on dual-task performance and episodic memory

2002 ◽  
Vol 55 (4) ◽  
pp. 1211-1240 ◽  
Author(s):  
Sian L. Beilock ◽  
Sarah A. Wierenga ◽  
Thomas H. Carr
Keyword(s):  
Recognition Memory ◽  
Episodic Memory ◽  
Task Performance ◽  
Dual Task ◽  
Secondary Task ◽  
Task Demands ◽  
Attention And Memory ◽  
Task Constraints ◽  
Episodic Memories ◽  
Task Conditions

Two experiments explored the attention and memory processes governing sensorimotor skill. Experiment 1 compared novice and experienced golf putting performance in single-task (putting in isolation) and dual-task conditions (putting while performing an auditory word search task). At specific intervals, participants also produced episodic descriptions of specific putts. Experiment 2 assessed novice performance following training on the same putting task. In Experiment 1, experienced golfers did not differ in putting accuracy from single- to dual-task conditions and, compared to novices, had higher recognition memory for words heard while putting but diminished episodic memories of specific putts. However, when using an s-shaped arbitrarily weighted “funny putter” designed to disrupt the mechanics of skill execution, experienced golfers produced extensive episodic memories of specific putts but showed decreased dual-task putting accuracy and recognition memory for secondary task words. Trained novices produced results intermediate between the untrained novices and experienced golfers. As predicted by current theories of practice-based automaticity, expertise leads to proceduralized control that does not require constant attention. Resources are free to devote to secondary task demands, yet episodic memory for primary task performance is impoverished. Novel task constraints (e.g., a funny putter) increase attention to execution, compromising secondary task performance but enhancing memory for skill execution.

scholarly journals Directional coupling of slow and fast hippocampal gamma with neocortical alpha/beta oscillations in human episodic memory

2019 ◽  
Vol 116 (43) ◽  
pp. 21834-21842 ◽  
Author(s):  
Benjamin J. Griffiths ◽  
George Parish ◽  
Frederic Roux ◽  
Sebastian Michelmann ◽  
Mircea van der Plas ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Memory Formation ◽  
Beta Power ◽  
Wide Range ◽  
Alpha Beta ◽  
Episodic Memories ◽  
Hippocampal Theta ◽  
Multisensory Information ◽  
Flow Of Information

Episodic memories hinge upon our ability to process a wide range of multisensory information and bind this information into a coherent, memorable representation. On a neural level, these 2 processes are thought to be supported by neocortical alpha/beta desynchronization and hippocampal theta/gamma synchronization, respectively. Intuitively, these 2 processes should couple to successfully create and retrieve episodic memories, yet this hypothesis has not been tested empirically. We address this by analyzing human intracranial electroencephalogram data recorded during 2 associative memory tasks. We find that neocortical alpha/beta (8 to 20 Hz) power decreases reliably precede and predict hippocampal “fast” gamma (60 to 80 Hz) power increases during episodic memory formation; during episodic memory retrieval, however, hippocampal “slow” gamma (40 to 50 Hz) power increases reliably precede and predict later neocortical alpha/beta power decreases. We speculate that this coupling reflects the flow of information from the neocortex to the hippocampus during memory formation, and hippocampal pattern completion inducing information reinstatement in the neocortex during memory retrieval.

scholarly journals Total recall: episodic memory retrieval, choice, and memory confidence in the rat

2020 ◽  
Author(s):  
Hannah R. Joo ◽  
Hexin Liang ◽  
Jason E Chung ◽  
Charlotte Geaghan-Breiner ◽  
Jiang Lan Fan ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Memory Task ◽  
Correct Choice ◽  
Decision Variable ◽  
Future Behavior ◽  
Episodic Memories ◽  
Past Experiences ◽  
Memory Confidence ◽  
Modern Machine

Episodic memory enables recollection of past experiences to guide future behavior. Humans know which memories to trust (high confidence) and which to doubt (low confidence). How memory retrieval, memory confidence, and memory-guided decisions are related, however, is not understood. Additionally, whether animals can assess confidence in episodic memories to guide behavior is unknown. We developed a spatial episodic memory task in which rats were incentivized to gamble their time: betting more following a correct choice yielded greater reward. Rat behavior reflected memory confidence, with higher temporal bets following correct choices. We applied modern machine learning to identify a memory decision variable, and built a generative model of memories evolving over time that accurately predicted both choices and confidence reports. Our results reveal in rats an ability thought to exist exclusively in primates, and introduce a unified model of memory dynamics, retrieval, choice, and confidence.

scholarly journals Directional coupling of slow and fast hippocampal gamma with neocortical alpha/beta oscillations in human episodic memory

2018 ◽  
Author(s):  
Benjamin J. Griffiths ◽  
George Parish ◽  
Frederic Roux ◽  
Sebastian Michelmann ◽  
Mircea van der Plas ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Memory Retrieval ◽  
Division Of Labour ◽  
Memory Formation ◽  
Beta Power ◽  
Wide Range ◽  
Directional Coupling ◽  
Alpha Beta ◽  
Episodic Memories ◽  
Flow Of Information

AbstractEpisodic memories hinge upon our ability to process a wide range of multisensory information and bind this information into a coherent, memorable representation. On a neural level, these two processes are thought to be supported by neocortical alpha/beta desynchronisation and hippocampal theta/gamma synchronisation, respectively. Intuitively, these two processes should couple to successfully create and retrieve episodic memories, yet this hypothesis has not been tested empirically. We address this by analysing human intracranial EEG data recorded during two associative memory tasks. We find that neocortical alpha/beta (8-20Hz) power decreases reliably precede and predict hippocampal “fast” gamma (60-80Hz) power increases during episodic memory formation; during episodic memory retrieval however, hippocampal “slow” gamma (40-50Hz) power increases reliably precede and predict later neocortical alpha/beta power decreases. We speculate that this coupling reflects the flow of information from neocortex to hippocampus during memory formation, and hippocampal pattern completion inducing information reinstatement in the neocortex during memory retrieval.Significance StatementEpisodic memories detail our personally-experienced past. The formation and retrieval of these memories has long been thought to be supported by a division of labour between the neocortex and the hippocampus, where the former processes event-related information and the latter binds this information together. However, it remains unclear how the two regions interact. We uncover directional coupling between these regions, with power decreases in the neocortex that precede and predict power increases in the hippocampus during memory formation. Fascinatingly, this process reverses during memory retrieval, with hippocampal power increases preceding and predicting neocortical power decreases. These results suggest a bidirectional flow of information between the neocortex and hippocampus is fundamental to the formation and retrieval of episodic memories.

scholarly journals The neural basis of episodic memory: evidence from functional neuroimaging

2002 ◽  
Vol 357 (1424) ◽  
pp. 1097-1110 ◽  
Author(s):  
Michael D. Rugg ◽  
Leun J. Otten ◽  
Richard N. A. Henson
Keyword(s):  
Episodic Memory ◽  
Neural Activity ◽  
Functional Neuroimaging ◽  
Neural Basis ◽  
Retrieval Task ◽  
Cortical Level ◽  
Episodic Information ◽  
Episodic Encoding ◽  
Episodic Memories ◽  
Anterior Prefrontal Cortex

We review some of our recent research using functional neuroimaging to investigate neural activity supporting the encoding and retrieval of episodic memories, that is, memories for unique events. Findings from studies of encoding indicate that, at the cortical level, the regions responsible for the effective encoding of a stimulus event as an episodic memory include some of the regions that are also engaged to process the event ‘online’. Thus, it appears that there is no single cortical site or circuit responsible for episodic encoding. The results of retrieval studies indicate that successful recollection of episodic information is associated with activation of lateral parietal cortex, along with more variable patterns of activity in dorsolateral and anterior prefrontal cortex. Whereas parietal regions may play a part in the representation of retrieved information, prefrontal areas appear to support processes that act on the products of retrieval to align behaviour with the demands of the retrieval task.

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