scholarly journals Autobiographically Significant Concepts: More Episodic than Semantic in Nature? An Electrophysiological Investigation of Overlapping Types of Memory

2015 ◽  
Vol 27 (1) ◽  
pp. 57-72 ◽  
Author(s):  
Louis Renoult ◽  
Patrick S. R. Davidson ◽  
Erika Schmitz ◽  
Lillian Park ◽  
Kenneth Campbell ◽  
...  

A common assertion is that semantic memory emerges from episodic memory, shedding the distinctive contexts associated with episodes over time and/or repeated instances. Some semantic concepts, however, may retain their episodic origins or acquire episodic information during life experiences. The current study examined this hypothesis by investigating the ERP correlates of autobiographically significant (AS) concepts, that is, semantic concepts that are associated with vivid episodic memories. We inferred the contribution of semantic and episodic memory to AS concepts using the amplitudes of the N400 and late positive component, respectively. We compared famous names that easily brought to mind episodic memories (high AS names) against equally famous names that did not bring such recollections to mind (low AS names) on a semantic task (fame judgment) and an episodic task (recognition memory). Compared with low AS names, high AS names were associated with increased amplitude of the late positive component in both tasks. Moreover, in the recognition task, this effect of AS was highly correlated with recognition confidence. In contrast, the N400 component did not differentiate the high versus low AS names but, instead, was related to the amount of general knowledge participants had regarding each name. These results suggest that semantic concepts high in AS, such as famous names, have an episodic component and are associated with similar brain processes to those that are engaged by episodic memory. Studying AS concepts may provide unique insights into how episodic and semantic memory interact.

2020 ◽  
Vol 14 ◽  
Author(s):  
Giorgia Committeri ◽  
Agustina Fragueiro ◽  
Maria Maddalena Campanile ◽  
Marco Lagatta ◽  
Ford Burles ◽  
...  

The medial temporal lobe supports both navigation and declarative memory. On this basis, a theory of phylogenetic continuity has been proposed according to which episodic and semantic memories have evolved from egocentric (e.g., path integration) and allocentric (e.g., map-based) navigation in the physical world, respectively. Here, we explored the behavioral significance of this neurophysiological model by investigating the relationship between the performance of healthy individuals on a path integration and an episodic memory task. We investigated the path integration performance through a proprioceptive Triangle Completion Task and assessed episodic memory through a picture recognition task. We evaluated the specificity of the association between performance in these two tasks by including in the study design a verbal semantic memory task. We also controlled for the effect of attention and working memory and tested the robustness of the results by including alternative versions of the path integration and semantic memory tasks. We found a significant positive correlation between the performance on the path integration the episodic, but not semantic, memory tasks. This pattern of correlation was not explained by general cognitive abilities and persisted also when considering a visual path integration task and a non-verbal semantic memory task. Importantly, a cross-validation analysis showed that participants' egocentric navigation abilities reliably predicted episodic memory performance. Altogether, our findings support the hypothesis of a phylogenetic continuity between egocentric navigation and episodic memory and pave the way for future research on the potential causal role of egocentric navigation on multiple forms of episodic memory.


Psychology ◽  
2019 ◽  
Author(s):  
Michael N. Jones ◽  
Johnathan Avery

Semantic memory refers to our general world knowledge that encompasses memory for concepts, facts, and the meanings of words and other symbolic units that constitute formal communication systems such as language or math. In the classic hierarchical view of memory, declarative memory was subdivided into two independent modules: episodic memory, which is our autobiographical store of individual events, and semantic memory, which is our general store of abstracted knowledge. However, more recent theoretical accounts have greatly reduced the independence of these two memory systems, and episodic memory is typically viewed as a gateway to semantic memory accessed through the process of abstraction. Modern accounts view semantic memory as deeply rooted in sensorimotor experience, abstracted across many episodic memories to highlight the stable characteristics and mute the idiosyncratic ones. A great deal of research in neuroscience has focused on both how the brain creates semantic memories and what brain regions share the responsibility for storage and retrieval of semantic knowledge. These include many classic experiments that studied the behavior of individuals with brain damage and various types of semantic disorders but also more modern studies that employ neuroimaging techniques to study how the brain creates and stores semantic memories. Classically, semantic memory had been treated as a miscellaneous area of study for anything in declarative memory that was not clearly within the realm of episodic memory, and formal models of meaning in memory did not advance at the pace of models of episodic memory. However, recent developments in neural networks and corpus-based tools for modeling text have greatly increased the sophistication of models of semantic memory. There now exist several good computational accounts to explain how humans transform first-order experience with the world into deep semantic representations and how these representations are retrieved and used in meaning-based behavioral tasks. The purpose of this article is to provide the reader with the more salient publications, reviews, and themes of major advances in the various subfields of semantic memory over the past forty-five years. For more in-depth coverage, we refer the reader to the manuscripts in the General Overviews section.


2019 ◽  
Vol 31 (10) ◽  
pp. 1549-1562 ◽  
Author(s):  
Alexander Jones ◽  
Emma V. Ward

Presenting events in a rhythm has been shown to enhance perception and facilitate responses for stimuli that appear in synchrony with the rhythm, but little is known about how rhythm during encoding influences later recognition. In this study, participants were presented with images of everyday objects in an encoding phase before a recognition task in which they judged whether or not objects were previously presented. Blockwise, object presentation during encoding followed either a rhythmic (constant, predictable) or arrhythmic (random, unpredictable) temporal structure, of which participants were unaware. Recognition was greater for items presented in a rhythmic relative to an arrhythmic manner. During encoding, there was a differential neural activity based on memory effect with larger positivity for rhythmic over arrhythmic stimuli. At recognition, memory-specific ERP components were differentially affected by temporal structure: The FN400 old/new effect was unaffected by rhythmic structure, whereas the late positive component old/new effect was observed only for rhythmically encoded items. Taken together, this study provides new evidence that memory-specific processing at recognition is affected by temporal structure at encoding.


2002 ◽  
Vol 357 (1424) ◽  
pp. 1097-1110 ◽  
Author(s):  
Michael D. Rugg ◽  
Leun J. Otten ◽  
Richard N. A. Henson

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.


2006 ◽  
Vol 11 (2) ◽  
pp. 21-35 ◽  
Author(s):  
Doug Knapp

This study used a phenomenological analysis to investigate the recollections of participants (N=36) of an interpretive program at Lowell National Historic Park. These individuals were interviewed six months following the experience. Four topic areas relating to the participants’ long-term memory of the interpretive program were identified: (a) personal connections with the tour, (b) program information retention, (c) positive visitor responses, and (d) ranger attributes. Results indicated that the personal connections made during the program were influential in creating vivid episodic memories. Some of the responses from the participants went beyond episodic information and could be associated with conceptual thinking associated with semantic memory or knowledge. The findings of this study, along with literature associated with long-term memory research, offer a potential model of learning for interpretation related to episodic/semantic memory systems.


2021 ◽  
Author(s):  
Candela S Leon ◽  
Matias Bonilla ◽  
Facundo A Urreta Benitez ◽  
Luis I Brusco ◽  
Jingyi Wang ◽  
...  

The threatening context of the COVID-19 pandemic provided a unique setting to study the effects of negative psychological symptoms on memory processes. Episodic memory is an essential function of the human being related to the ability to store and remember experiences and anticipate possible events in the future. Studying this function in this context is crucial to help understand what effects the pandemic will have on the formation of episodic memories. To study this, the formation of episodic memories was evaluated by free recall, recognition, and episode order tasks for an aversive and neutral content. The results indicated that aversive episodic memory is impaired both in the free recall task and in the recognition task. Even the beneficial effect that emotional memory usually has for the episodic order was undermined as there were no differences between the neutral and aversive condition. The present work adds to the evidence that indicates that the level of activation does not modify memory processes in a linear way, which also depends on the type of evocation that people are asked and the characteristics of the content to be encoded.


2021 ◽  
Vol 11 (4) ◽  
pp. 410
Author(s):  
Simon Ruch ◽  
Kristoffer Fehér ◽  
Stephanie Homan ◽  
Yosuke Morishima ◽  
Sarah Maria Mueller ◽  
...  

Slow-wave sleep (SWS) has been shown to promote long-term consolidation of episodic memories in hippocampo–neocortical networks. Previous research has aimed to modulate cortical sleep slow-waves and spindles to facilitate episodic memory consolidation. Here, we instead aimed to modulate hippocampal activity during slow-wave sleep using transcranial direct current stimulation in 18 healthy humans. A pair-associate episodic memory task was used to evaluate sleep-dependent memory consolidation with face–occupation stimuli. Pre- and post-nap retrieval was assessed as a measure of memory performance. Anodal stimulation with 2 mA was applied bilaterally over the lateral temporal cortex, motivated by its particularly extensive connections to the hippocampus. The participants slept in a magnetic resonance (MR)-simulator during the recordings to test the feasibility for a future MR-study. We used a sham-controlled, double-blind, counterbalanced randomized, within-subject crossover design. We show that stimulation vs. sham significantly increased slow-wave density and the temporal coupling of fast spindles and slow-waves. While retention of episodic memories across sleep was not affected across the entire sample of participants, it was impaired in participants with below-average pre-sleep memory performance. Hence, bi-temporal anodal direct current stimulation applied during sleep enhanced sleep parameters that are typically involved in memory consolidation, but it failed to improve memory consolidation and even tended to impair consolidation in poor learners. These findings suggest that artificially enhancing memory-related sleep parameters to improve memory consolidation can actually backfire in those participants who are in most need of memory improvement.


2021 ◽  
Vol 30 (2S) ◽  
pp. 920-932
Author(s):  
Elisabeth Cochran D'Angelo ◽  
Beth A. Ober ◽  
Gregory K. Shenaut

Purpose The study aimed to test a combination of semantic memory and traditional episodic memory therapies on episodic memory deficits in adults with traumatic brain injury. Method Twenty-five participants who had been diagnosed with traumatic brain injury and had episodic memory deficits were randomly assigned either to a combined memory treatment group ( n = 16) or to a wait-list control group ( n = 9). Before and after treatment, they completed standardized neuropsychological testing for episodic memory and related cognitive domains, including the California Verbal Learning Test–Second Edition, the Controlled Oral Word Association Test, the University of Southern California Repeatable Episodic Memory Test, the Wechsler Abbreviated Scale of Intelligence–Second Edition Matrices, the Test of Everyday Attention, the Memory Assessment Clinics Self-Rating Scale, the Expressive Vocabulary Test–Second Edition, and the Story Recall subtest from the Rivermead Behavioural Memory Test. In addition to a traditional episodic memory therapy, the treatment group received a novel semantic memory–focused therapy, which involved participants finding meaningful connections between diverse concepts represented by sets of two or three words. Results The treatment group demonstrated statistically significant improvement in memory for list learning tasks, and there was a significant difference from pretest to posttest between the treatment group and the wait-list control group. Clinical significance was demonstrated for the treatment group using minimally important difference calculations. Conclusion Combined memory therapy resulted in significant improvements in episodic memory, semantic memory, and attention, in comparison to no treatment. Supplemental Material https://doi.org/10.23641/asha.14049968


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