Item memory, context memory and the hippocampus: fMRI evidence

Context memory retrieval tasks often implicate the left ventrolateral pFC (LVPFC) during functional imaging. Although this region has been linked to controlled semantic processing of materials, it may also play a more general role in selecting among competing episodic representations during demanding retrieval tasks. Thus, the LVPFC response during context memory retrieval may reflect either semantic processing of memoranda or adjudication of interfering episodic memories evoked by memoranda. To distinguish between these hypotheses, we contrasted context and item memory retrieval tasks for meaningful and nonmeaningful memoranda using fMRI. Increased LVPFC activation during context compared with item memory only occurred for meaningful memory probes. In contrast, even demanding context retrieval for nonmeaningful materials failed to engage LVPFC. These data demonstrate that the activation previously seen during episodic tasks likely reflects semantic processing of the probes during episodic retrieval attempt, not the selection among competing elicited episodic representations. Posterior middle temporal gyrus and the body/head of the caudate demonstrated the same selective response as LVPFC, although resting state functional connectivity analyses suggested that these two regions likely shared separate functional relationships with the LVPFC.

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A Rapid, Hippocampus-Dependent, Item-Memory Signal that Initiates Context Memory in Humans

Current Biology ◽

10.1016/j.cub.2012.10.055 ◽

2012 ◽

Vol 22 (24) ◽

pp. 2369-2374 ◽

Cited By ~ 24

Author(s):

Aidan J. Horner ◽

David G. Gadian ◽

Lluis Fuentemilla ◽

Sebastian Jentschke ◽

Faraneh Vargha-Khadem ◽

...

Keyword(s):

Item Memory ◽

Context Memory

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The Generation Effect Revisited: Fewer Generation Constraints Enhances Item and Context Memory

10.31234/osf.io/3td4k ◽

2018 ◽

Author(s):

Matthew P. McCurdy ◽

Ryan Leach ◽

Eric D. Leshikar

Keyword(s):

Generation Effect ◽

Word Fragment ◽

Item Memory ◽

Task Constraint ◽

Free Response ◽

Generation Task ◽

Constraint Generation ◽

Memory Representations ◽

Context Memory

Self-generated information is often better remembered than non-self-generated information. This effect has been robust for item memory (i.e., the content of information) across many different experiments, but inconsistent for context memory (e.g., memory for the extraneous details of information, such as source). Previous studies examining the generation effect, however, have often applied constraints on the generation task possibly limiting the memory benefit from self-generation. In three experiments, we compared item and context memory for a lower-constraint generation task (i.e., free response to a cue word) relative to higher-constraint generation tasks (Exp. 1 & 2: scramble; Exp. 3: word fragment). Results showed that participants had better item and context memory in the lower-constraint compared to higher-constraint generation tasks. Overall, these experiments suggest that that the mnemonic benefits of self-generation depend on the level of task constraint. This study further advances the idea that self-generation is a powerful mnemonic that leads to enriched memory representations for both the item and context, especially when fewer generation constraints are imposed.

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Trial-by-trial fluctuations in post-stimulus attention during memory encoding predict subsequent associative context memory performance

10.1101/2021.02.16.431454 ◽

2021 ◽

Author(s):

Abdelhalim Elshiekh ◽

M. Natasha Rajah

Keyword(s):

Memory Performance ◽

Formation Rate ◽

Spatial Location ◽

Item Memory ◽

Memory Encoding ◽

Attentional State ◽

Fixation Cross ◽

Trial Basis ◽

The Impact ◽

Context Memory

AbstractEpisodic memory formation rate varies over time partly due to fluctuations in attentional state during memory encoding. Emerging evidence suggests that fluctuations in pre- and/or post-stimulus attention during encoding impact subsequent memory performance. It remains unclear how these fluctuations may differentially impact the subsequent retrieval of items alone, compared to items + their contextual details (associative context memory). In this study, we explored this in 30 healthy younger adults (21-34 years old). We developed the Montreal Attention at Encoding (MAET) task where on each encoding trial, participants responded as quickly as possible to a central fixation cross that expanded in size after a random duration. They then had to encode a picture of an object and its spatial location. Memory for the object-location associations was tested during retrieval. Response time (RT) to the fixation cross presented prior to each object gauged pre-stimulus attention levels on a trial-by-trial basis, while RT to the fixation cross that ensued each object indexed post-stimulus attention levels. Within-subject logistic regressions were used to predict context and item memory performance from pre- and post-stimulus RTs. Results revealed that encoding pre-stimulus attentional levels did not differentially predict context vs. item memory. However, post-stimulus RTs did predict subsequent context retrieval such that, longer post-stimulus RT to the fixation was related to poorer subsequent context retrieval. This study introduces a novel paradigm for investigating the impact of attentional state at encoding on subsequent memory performance and indicate a link between post-stimulus delays in attention-related RT and associative encoding success.

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Fewer Generation Constraints Increase the Generation Effect for Item and Source Memory through Enhanced Relational Processing

10.31234/osf.io/cyj8q ◽

2020 ◽

Author(s):

Matthew P. McCurdy ◽

Allison Sklenar ◽

Andrea N. Frankenstein ◽

Eric D. Leshikar

Keyword(s):

Source Memory ◽

Theoretical Work ◽

Cued Recall ◽

Generation Effect ◽

Item Memory ◽

Control Task ◽

Relational Processing ◽

Constraint Generation ◽

Font Color ◽

Context Memory

Memory is often better for information that is self-generated versus read (i.e., the generation effect). Theoretical work attributes the generation effect to two mechanisms: enhanced item-specific and relational processing (i.e., the two-factor theory). Recent work has demonstrated that the generation effect increases when generation tasks place lower, relative to higher, constraints on what participants can self-generate. This study examined whether the effects of generation constraint on memory might be attributable to either mechanism of the two-factor theory. Across three experiments, participants encoded word pairs in two generation conditions (lower- and higher-constraint) and a read control task, followed by a memory test for item memory and two context memory details (source and font color). The results of these experiments support the idea that lower-constraint generation increases the generation effect via enhanced relational processing, as measured through both recognition and cued recall tasks. Results further showed that lower-constraint generation improves context memory for conceptual context (source), but not perceptual context (color), suggesting that this enhanced relational processing may extend to conceptually related details of an item. Overall, these results provide more evidence that fewer generation constraints increase the generation effect and implicate enhanced relational processing as a mechanism for this improvement.

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A selective benefit of transient, but not sustained, reward to memory formation

10.31234/osf.io/zcs3t ◽

2021 ◽

Author(s):

Avery S. Gholston ◽

Kimberly Sarah Chiew

Keyword(s):

Temporal Dynamics ◽

Memory Performance ◽

Response Speed ◽

Memory Formation ◽

Task Engagement ◽

Item Memory ◽

Mixed Block ◽

Memory Encoding ◽

Behavioral Experiments ◽

Context Memory

Reward benefits to memory formation have been robustly linked to dopaminergic activity. Despite established characterization of dopaminergic mechanisms as operating at multiple timescales, potentially supporting distinct functional outcomes, the temporal dynamics by which reward might modulate memory encoding are just beginning to be investigated. In the present study, we leveraged a mixed block/event experimental design to disentangle transient and sustained reward influences on task engagement and subsequent recognition memory in an adapted monetary-incentive encoding (MIE) paradigm. Across three behavioral experiments, transient and sustained reward modulation of item and context memory was probed, at both 24-hour and ~10-minute retention intervals, to investigate the importance of overnight consolidation. In general, we observed that transient reward was associated with enhanced item memory encoding, while sustained reward modulated task engagement at encoding (specifically, increasing response speed) but did not confer a benefit to subsequent memory performance. Notably, reward benefits to item memory performance were somewhat inconsistent across the three experiments, and in contrast to predictions, we did not observe reward modulation of context memory performance or amplification of reward effects by overnight consolidation. Taken together, the observed pattern of behavior suggests potentially distinct roles for transient and sustained reward in memory encoding and cognitive performance and suggests that further investigation of the temporal dynamics of dopaminergic contributions to memory formation will advance understanding of motivated memory.

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Encoding Variability: When Pattern Reactivation Does Not Benefit Context Memory

10.1101/586446 ◽

2019 ◽

Author(s):

Carolin Sievers ◽

Fraser W. Smith ◽

Janak Saada ◽

Jon S. Simons ◽

Louis Renoult

Keyword(s):

Cingulate Cortex ◽

Posterior Cingulate Cortex ◽

Item Memory ◽

Task Condition ◽

Opposite Pattern ◽

Posterior Cingulate ◽

Contextual Features ◽

Task Encoding ◽

Encoding Variability ◽

Context Memory

AbstractA growing body of evidence suggests that neural pattern reactivation supports successful memory formation across multiple study episodes. Previous studies investigating the beneficial effects of repeated encoding typically presented the same stimuli repeatedly under the same encoding task instructions. In contrast, repeating stimuli in different contexts is associated with superior item memory, but poorer memory for contextual features varying across repetitions. In the present functional magnetic-resonance imaging (fMRI) study, we predicted dissociable mechanisms to underlie the successful formation of context memory when the context in which stimuli are repeated is either held constant or varies at each stimulus presentation. Twenty participants studied names of famous people four times, either in the same task repeatedly, or in four different encoding tasks. This was followed by a surprise recognition memory test, including a source judgement about the encoding task. Behaviourally, different task encoding compared to same task encoding was associated with fewer correct context memory judgements but also better item memory, as reflected in fewer misses. Searchlight representational similarity analysis revealed fMRI pattern reactivation in the posterior cingulate cortex to be higher for correct compared to incorrect source memory judgements in the same task condition, with the opposite pattern being observed in the different task condition. It was concluded that higher levels of pattern reactivation in the posterior cingulate cortex index generalisation across context information, which in turn may improve item memory performance during encoding variability but at the cost of contextual features.

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Cue- versus Probe-dependent Prefrontal Cortex Activity during Contextual Remembering

Journal of Cognitive Neuroscience ◽

10.1162/jocn.2006.18.9.1439 ◽

2006 ◽

Vol 18 (9) ◽

pp. 1439-1452 ◽

Cited By ~ 55

Author(s):

Ian G. Dobbins ◽

Sanghoon Han

Keyword(s):

Prefrontal Cortex ◽

Functional Neuroimaging ◽

Item Memory ◽

Precentral Gyrus ◽

Related Activity ◽

Contextual Memory ◽

Frontopolar Cortex ◽

Response Profiles ◽

Different Response ◽

Context Memory

Functional neuroimaging comparisons of context and item memory frequently implicate the left prefrontal cortex (PFC) during the recovery of contextually specific memories. However, because cues and probes are often presented simultaneously, this activity could reflect operations involved in planning retrieval or instead reflect later operations dependent upon the memory probes themselves, such as evaluation of probe-evoked recollections. More importantly, planning-related activity, wherein subjects reinstate details outlining the nature of desired remembrances, should occur in response to contextual memory cues even before retrieval probes are available. Using event-related functional magnetic resonance imaging, we tested this by dissociating cue- from probe-related activity during context memory for pictures. Cues forewarning contextual memory demands yielded more activity than those forewarning item memory in the left lateral precentral gyrus, midline superior frontal gyrus, and right frontopolar cortex. Thus, these anticipatory, cue-based activations indicated whether upcoming probe decisions would require contextually specific memories or not. In contrast, the left dorsolateral/midventrolateral and anterior ventrolateral PFC areas did not show differential activity until the probes were actually presented, demonstrating greater activity for context than for item memory probes. Direct comparison of proximal left PFC regions demonstrated qualitatively different response profiles across cue versus probe periods for lateral precentral versus dorsolateral regions. These results potentially isolate contextual memory-planning-related processes from subsequent processes such as the evaluation of recollections, which are necessarily dependent on individual probe features. They also demonstrate that contextual remembering recruits multiple, functionally distinct PFC processes.

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Theories of the Generation Effect and the Impact of Generation Constraint: A Meta-analytic Review

10.31234/osf.io/h5vw4 ◽

2020 ◽

Author(s):

Matthew P. McCurdy ◽

Wolfgang Viechtbauer ◽

Allison Sklenar ◽

Andrea N. Frankenstein ◽

Eric D. Leshikar

Keyword(s):

Boundary Conditions ◽

Meta Analysis ◽

Generation Effect ◽

Item Memory ◽

Future Research ◽

Memory Mechanism ◽

Analytic Review ◽

Future Work ◽

The Impact ◽

Context Memory

The generation effect is the memory benefit for self-generated compared to read or experimenter provided information. In recent decades, numerous theories have been proposed to explain the memory mechanism(s) and boundary conditions of the generation effect. In this meta-analysis and theoretical review, we analyzed 126 articles (310 experiments, 1653 estimates) to assess seven prominent theories to determine which theories are supported by the existing literature. Because some theories focus on item memory (memory for the generated target) and others focus on context memory (memory for details associated with the generated target), we examined memory effects for both types of details (item, context) in this meta-analysis. Further, we assessed the influence of generation constraint (how constrained participants are to a generate a certain response), which recent work has shown impacts the magnitude of the generation effect. Overall, the results of this meta-analysis support some theoretical accounts, but not others, as explanatory mechanisms of the generation effect. Results further showed that generation constraint significantly moderates the magnitude of the generation effect, suggesting that this factor should be rigorously investigated in future work. Overall, this meta-analysis provides a review and examination of generation effect theories, and reveals important areas of future research.

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Positive Arousal Enhances the Consolidation of Item Memory

Swiss Journal of Psychology ◽

10.1024/1421-0185/a000151 ◽

2015 ◽

Vol 74 (2) ◽

pp. 91-104 ◽

Cited By ~ 1

Author(s):

Bo Wang

Keyword(s):

Episodic Memory ◽

Memory Consolidation ◽

Source Memory ◽

Emotional Arousal ◽

Theoretical Models ◽

Memory Test ◽

Learning Phase ◽

Item Memory ◽

Memory Tests ◽

Immediate Memory

Emotional arousal induced after learning has been shown to modulate memory consolidation. However, it is unclear whether the effect of postlearning arousal can extend to different aspects of memory. This study examined the effect of postlearning positive arousal on both item memory and source memory. Participants learned a list of neutral words and took an immediate memory test. Then they watched a positive or a neutral videoclip and took delayed memory tests after either 25 minutes or 1 week had elapsed after the learning phase. In both delay conditions, positive arousal enhanced consolidation of item memory as measured by overall recognition. Furthermore, positive arousal enhanced consolidation of familiarity but not recollection. However, positive arousal appeared to have no effect on consolidation of source memory. These findings have implications for building theoretical models of the effect of emotional arousal on consolidation of episodic memory and for applying postlearning emotional arousal as a technique of memory intervention.

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