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British Journal of Anaesthesia Dec 2016
Topics: Anesthesia; Humans; Intraoperative Complications; Mental Recall; Patient Satisfaction; Stress, Psychological
PubMed: 27956667
DOI: 10.1093/bja/aew384 -
Nature Reviews. Neuroscience Aug 2010There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of circadian rhythms. However, it is... (Review)
Review
There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of circadian rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie circadian rhythmicity and long-term memory formation.
Topics: Animals; Circadian Rhythm; Humans; Long-Term Potentiation; Memory; Mental Recall; Molecular Dynamics Simulation; Retention, Psychology
PubMed: 20648063
DOI: 10.1038/nrn2881 -
Nature Communications Jul 2022When we remember events, we often do not only recall individual events, but also the connections between them. However, extant research has focused on how humans segment...
When we remember events, we often do not only recall individual events, but also the connections between them. However, extant research has focused on how humans segment and remember discrete events from continuous input, with far less attention given to how the structure of connections between events impacts memory. Here we conduct a functional magnetic resonance imaging study in which participants watch and recall a series of realistic audiovisual narratives. By transforming narratives into networks of events, we demonstrate that more central events-those with stronger semantic or causal connections to other events-are better remembered. During encoding, central events evoke larger hippocampal event boundary responses associated with memory formation. During recall, high centrality is associated with stronger activation in cortical areas involved in episodic recollection, and more similar neural representations across individuals. Together, these results suggest that when humans encode and retrieve complex real-world experiences, the reliability and accessibility of memory representations is shaped by their location within a network of events.
Topics: Brain Mapping; Hippocampus; Humans; Magnetic Resonance Imaging; Memory, Episodic; Mental Recall; Reproducibility of Results
PubMed: 35869083
DOI: 10.1038/s41467-022-31965-2 -
Topics in Cognitive Science Oct 2019The study of memory and remembering has traditionally either stripped meaning away from acts of remembering to reveal the "raw material of memory" or explored how...
The study of memory and remembering has traditionally either stripped meaning away from acts of remembering to reveal the "raw material of memory" or explored how meaning guides the reconstruction of the past. In reflecting on the contributions to this topic, there appears to be an emerging "third-way," which holds that there is an inextricable relation between conversations and remembering. The articles in this volume exemplify how conversing is often an act of remembering and represent approaches to memory that might not otherwise be taken if one were to study memory as a within-individual phenomenon. The implications of this approach are far-ranging and present the opportunity to pose new questions about the nature of remembering as it unfolds in conversation. The contributing articles have expanded the scope of what memory researchers can study by adopting a relatively straightforward assumption about the sociality of remembering and the role of the conversation in the social process.
Topics: Communication; Humans; Interpersonal Relations; Memory; Mental Recall
PubMed: 31385446
DOI: 10.1111/tops.12437 -
Philosophical Transactions of the Royal... Apr 2003Our primary research interest is to understand the molecular and cellular mechanisms on neuronal circuitry underlying the acquisition, consolidation and retrieval of... (Review)
Review
Our primary research interest is to understand the molecular and cellular mechanisms on neuronal circuitry underlying the acquisition, consolidation and retrieval of hippocampus-dependent memory in rodents. We study these problems by producing genetically engineered (i.e. spatially targeted and/or temporally restricted) mice and analysing these mice by multifaceted methods including molecular and cellular biology, in vitro and in vivo physiology and behavioural studies. We attempt to identify deficits at each of the multiple levels of complexity in specific brain areas or cell types and deduce those deficits that underlie specific learning or memory. We will review our recent studies on the acquisition, consolidation and recall of memories that have been conducted with mouse strains in which genetic manipulations were targeted to specific types of cells in the hippocampus or forebrain of young adult mice.
Topics: Animals; Genetic Techniques; Hippocampus; Learning; Memory; Mental Recall; Neurosciences
PubMed: 12740125
DOI: 10.1098/rstb.2002.1243 -
Cortex; a Journal Devoted To the Study... Jan 2023The recall and visualization of people and places from memory is an everyday occurrence, yet the neural mechanisms underpinning this phenomenon are not well understood....
The recall and visualization of people and places from memory is an everyday occurrence, yet the neural mechanisms underpinning this phenomenon are not well understood. In particular, the temporal characteristics of the internal representations generated by active recall are unclear. Here, we used magnetoencephalography (MEG) and multivariate pattern analysis to measure the evolving neural representation of familiar places and people across the whole brain when human participants engage in active recall. To isolate self-generated imagined representations, we used a retro-cue paradigm in which participants were first presented with two possible labels before being cued to recall either the first or second item. We collected personalized labels for specific locations and people familiar to each participant. Importantly, no visual stimuli were presented during the recall period, and the retro-cue paradigm allowed the dissociation of responses associated with the labels from those corresponding to the self-generated representations. First, we found that following the retro-cue it took on average ∼1000 ms for distinct neural representations of freely recalled people or places to develop. Second, we found distinct representations of personally familiar concepts throughout the 4 s recall period. Finally, we found that these representations were highly stable and generalizable across time. These results suggest that self-generated visualizations and recall of familiar places and people are subserved by a stable neural mechanism that operates relatively slowly when under conscious control.
Topics: Humans; Cues; Mental Recall; Brain; Brain Mapping; Magnetoencephalography
PubMed: 36459788
DOI: 10.1016/j.cortex.2022.08.014 -
Neural Networks : the Official Journal... Jul 2022Categorical relationships between objects are encoded as overlapped neural representations in the brain, where the more similar the objects are, the larger the...
Categorical relationships between objects are encoded as overlapped neural representations in the brain, where the more similar the objects are, the larger the correlations between their evoked neuronal responses. These representation correlations, however, inevitably incur interference when memories are retrieved. Here, we propose that neural feedback, which is widely observed in the brain but whose function remains largely unknown, contributes to disentangle neural correlations to improve information retrieval. We study a hierarchical neural network storing the hierarchical categorical information of objects, and information retrieval goes from rough-to-fine, aided by the push-pull neural feedback. We elucidate that the push and the pull components of the feedback suppress the interferences due to the representation correlations between objects from different and the same categories, respectively. Our model reproduces the push-pull phenomenon observed in neural data and sheds light on our understanding of the role of feedback in neural information processing.
Topics: Brain; Feedback; Information Storage and Retrieval; Mental Recall; Neurons
PubMed: 35472729
DOI: 10.1016/j.neunet.2022.03.042 -
Memory (Hove, England) 2016In this study, we examined mechanisms that underlie free-recall performance in bilinguals' first language (L1) and second language (L2) through the prism of...
In this study, we examined mechanisms that underlie free-recall performance in bilinguals' first language (L1) and second language (L2) through the prism of serial-position effects. On free-recall tasks, a typical pattern of performance follows a U-shaped serial-position curve, where items from the beginning of the list (the primacy effect) and items from the end of the list (the recency effect) are recalled with higher accuracy than items from the middle of the list. The present study contrasted serial-position effects on the free-recall task in Korean-English bilinguals' L1 vs. L2 and examined the relationship between an independent working memory (WM) measure and serial-position effects in bilinguals' two languages. Results revealed stronger pre-recency (primacy and middle) effects in L1 than in L2, but similar recency effects in the two languages. A close association was observed between WM and recall performance in the pre-recency region in the L1 but not in the L2. Together, these findings suggest that linguistic knowledge constrains free-recall performance in bilinguals, but only in the pre-recency region.
Topics: Adult; Attention; Female; Humans; Male; Mental Recall; Multilingualism; Neuropsychological Tests; Serial Learning; Young Adult
PubMed: 25730660
DOI: 10.1080/09658211.2015.1013557 -
Cell Reports Dec 2023How memories are organized in the brain influences whether they are remembered discretely versus linked with other experiences or whether generalized information is...
How memories are organized in the brain influences whether they are remembered discretely versus linked with other experiences or whether generalized information is applied to entirely novel situations. Here, we used scFLARE2 (single-chain fast light- and activity-regulated expression 2), a temporally precise tagging system, to manipulate mouse lateral amygdala neurons active during one of two 3 min threat experiences occurring close (3 h) or further apart (27 h) in time. Silencing scFLARE2-tagged neurons showed that two threat experiences occurring at distal times are dis-allocated to orthogonal engram ensembles and remembered discretely, whereas the same two threat experiences occurring in close temporal proximity are linked via co-allocation to overlapping engram ensembles. Moreover, we found that co-allocation mediates memory generalization applied to a completely novel stimulus. These results indicate that endogenous temporal evolution of engram ensemble neuronal excitability determines how memories are organized and remembered and that this would not be possible using conventional immediate-early gene-based tagging methods.
Topics: Mice; Animals; Memory; Fear; Neurons; Brain; Mental Recall
PubMed: 38103203
DOI: 10.1016/j.celrep.2023.113592 -
Trends in Cognitive Sciences Sep 2019What are the principles that govern whether neural representations move apart (differentiate) or together (integrate) as a function of learning? According to supervised... (Review)
Review
What are the principles that govern whether neural representations move apart (differentiate) or together (integrate) as a function of learning? According to supervised learning models that are trained to predict outcomes in the world, integration should occur when two stimuli predict the same outcome. Numerous findings support this, but - paradoxically - some recent fMRI studies have found that pairing different stimuli with the same associate causes differentiation, not integration. To explain these and related findings, we argue that supervised learning needs to be supplemented with unsupervised learning that is driven by spreading activation in a U-shaped way, such that inactive memories are not modified, moderate activation of memories causes weakening (leading to differentiation), and higher activation causes strengthening (leading to integration).
Topics: Association Learning; Humans; Machine Learning; Mental Recall
PubMed: 31358438
DOI: 10.1016/j.tics.2019.06.007