-
Seminars in Cell & Developmental Biology May 2022Memory is composed of various phases including cellular consolidation, systems consolidation, reconsolidation, and extinction. In the last few years it has been shown... (Review)
Review
Memory is composed of various phases including cellular consolidation, systems consolidation, reconsolidation, and extinction. In the last few years it has been shown that simple association memories can be encoded by a subset of the neuronal population called engram cells. Activity of these cells is necessary and sufficient for the recall of association memory. However, it is unclear which molecular mechanisms allow cellular engrams to encode the diverse phases of memory. Further research is needed to examine the possibility that it is the synapses between engram cells (the synaptic engram) that constitute the memory. In this review we summarize recent findings on cellular engrams with a focus on different phases of memory, and discuss the distinct molecular mechanism required for cellular and synaptic engrams.
Topics: Mental Recall; Neurons; Synapses
PubMed: 34103208
DOI: 10.1016/j.semcdb.2021.05.033 -
Journal of Sleep Research Aug 2022Several studies have tried to identify the neurobiological bases of dream experiences, nevertheless some questions are still at the centre of the debate. Here, we... (Review)
Review
Several studies have tried to identify the neurobiological bases of dream experiences, nevertheless some questions are still at the centre of the debate. Here, we summarise the main open issues concerning the neuroscientific study of dreaming. After overcoming the rapid eye movement (REM) - non-REM (NREM) sleep dichotomy, investigations have focussed on the specific functional or structural brain features predicting dream experience. On the one hand, some results underlined that specific trait-like factors are associated with higher dream recall frequency. On the other hand, the electrophysiological milieu preceding dream report upon awakening is a crucial state-like factor influencing the subsequent recall. Furthermore, dreaming is strictly related to waking experiences. Based on the continuity hypothesis, some findings reveal that dreaming could be modulated through visual, olfactory, or somatosensory stimulations. Also, it should be considered that the indirect access to dreaming remains an intrinsic limitation. Recent findings have revealed a greater concordance between parasomnia-like events and dream contents. This means that parasomnia episodes might be an expression of the ongoing mental sleep activity and could represent a viable direct access to dream experience. Finally, we provide a picture on nightmares and emphasise the possible role of oneiric activity in psychotherapy. Overall, further efforts in dream science are needed (a) to develop a uniform protocol to study dream experience, (b) to introduce and integrate advanced techniques to better understand whether dreaming can be manipulated, (c) to clarify the relationship between parasomnia events and dreaming, and (d) to determine the clinical valence of dreams.
Topics: Dreams; Humans; Mental Recall; Parasomnias; Sleep; Sleep, REM
PubMed: 35417930
DOI: 10.1111/jsr.13609 -
Nature Communications Nov 2023Inaccessibility of stored memory in ensemble cells through the forgetting process causes animals to be unable to respond to natural recalling cues. While accumulating...
Inaccessibility of stored memory in ensemble cells through the forgetting process causes animals to be unable to respond to natural recalling cues. While accumulating evidence has demonstrated that reactivating memory-stored cells can switch cells from an inaccessible state to an accessible form and lead to recall of previously learned information, the underlying cellular and molecular mechanisms remain elusive. The current study used Drosophila as a model to demonstrate that the memory of one-trial aversive olfactory conditioning, although inaccessible within a few hours after learning, is stored in KCαβ and retrievable after mild retraining. One-trial aversive conditioning triggers protein synthesis to form a long-lasting cellular memory trace, approximately 20 days, via creb in KCαβ, and a transient cellular memory trace, approximately one day, via orb in MBON-α3. PPL1-α3 negatively regulates forgotten one-trial conditioning memory retrieval. The current study demonstrated that KCαβ, PPL1-α3, and MBON-α3 collaboratively regulate the formation of forgotten one-cycle aversive conditioning memory formation and retrieval.
Topics: Animals; Drosophila; Memory; Learning; Conditioning, Psychological; Mental Recall
PubMed: 37935667
DOI: 10.1038/s41467-023-42753-x -
Neuron Sep 2020The hippocampus and its extended network contribute to encoding and recall of episodic experiences. Drawing from recent anatomical, physiological, and behavioral... (Review)
Review
The hippocampus and its extended network contribute to encoding and recall of episodic experiences. Drawing from recent anatomical, physiological, and behavioral studies, we propose that hippocampal engrams function as indices to mediate memory recall. We broaden this idea to discuss potential relationships between engrams and hippocampal place cells, as well as the molecular, cellular, physiological, and circuit determinants of engrams that permit flexible routing of information to intra- and extrahippocampal circuits for reinstatement, a feature critical to memory indexing. Incorporating indexing into frameworks of memory function opens new avenues of study and even therapies for hippocampal dysfunction.
Topics: Animals; Hippocampus; Humans; Mental Recall; Place Cells
PubMed: 32763146
DOI: 10.1016/j.neuron.2020.07.011 -
Psychological Research Sep 2022This review reanalyses the data from four experiments originally designed to test the fragmentation hypothesis. Participants were asked to recall triple or quadruple... (Review)
Review
This review reanalyses the data from four experiments originally designed to test the fragmentation hypothesis. Participants were asked to recall triple or quadruple associates, cued by each of their components in turn, and to guess if they could not remember. There were many errors in recall and many of those errors were repetitions of previous errors. This reanalysis focuses, not on the fragmentation hypothesis, but on the repetition of errors. It works backwards through sequences of test trials to discover the best prior match to the responses on each trial. It reports frequencies of different categories of repetition, conditional probabilities of repetition, correct recalls, and the probability of repetition in relation to the lag between trial and match in the test sequence. These results may be summarised as (1) every event (a stimulus or a response or just a retrieval) to which the participant attends is separately recorded in memory, creating an ordered record of those events that have engaged the participant's attention; (2) the compilation of the record is automatic; while attention to a stimulus is at the participant's disposal, the consequent entry into memory is not, and (3) the retrieval of a potential response from memory is spontaneous; that retrieval becomes an overt response if it is compatible with the cue. This makes sense of a number of historic anomalies in the study of recall and informs some contemporary problems in the study of short-term memory.
Topics: Cues; Humans; Memory, Short-Term; Mental Recall
PubMed: 35288792
DOI: 10.1007/s00426-021-01598-z -
Proceedings of the National Academy of... Mar 2022
Topics: Cues; Mental Recall
PubMed: 35290116
DOI: 10.1073/pnas.2201332119 -
American Journal of Pharmaceutical... Aug 2020The ability to follow instructions is an important aspect of everyday life. Depending on the setting and context, following instructions results in outcomes that have... (Review)
Review
The ability to follow instructions is an important aspect of everyday life. Depending on the setting and context, following instructions results in outcomes that have various degrees of impact. In a clinical setting, following instructions may affect life or death. Within the context of the academic setting, following instructions or failure to do so can impede general learning and development of desired proficiencies. Intuitively, one might think that following instructions requires simply reading instructional text or paying close attention to verbal directions and performing the intended action afterward. This commentary provides a brief overview of the cognitive architecture required for following instructions and will explore social behaviors and mode of instruction as factors further impacting this ability.
Topics: Attention; Cognition; Cooperative Behavior; Education, Pharmacy; Humans; Learning; Mental Recall; Reading; Social Behavior
PubMed: 32934383
DOI: 10.5688/ajpe7779 -
Cognition Jan 2023Two experiments examined the effects of deliberately suppressing retrieval of motor sequences on their later recall, in the think/no-think paradigm (Anderson & Green,...
Two experiments examined the effects of deliberately suppressing retrieval of motor sequences on their later recall, in the think/no-think paradigm (Anderson & Green, 2001). After several motor sequences had been associated with individual cues through repeated practice cycles, a subset of these sequences was retrieved in response to their respective cues (think trials), whereas other sequences were suppressed. In such no-think trials, cues were shown but participants were instructed to withhold the associated motor response and to suppress its recollection. We found that suppressing retrieval impaired later memory performance for the suppressed sequences in comparison to items that were not cued at all after their initial training (baseline sequences). Suppression impaired later sequence recall and sequence speed although in different ways depending on the training level: with higher initial training of sequences (Experiment 1), suppression impaired reaction time, but not recall accuracy; with lower initial training (Experiment 2), suppression reduced recall accuracy. Reaction time analyses revealed a consistent slowing of movement execution for suppressed sequences. These findings show that inhibitory control processes engaged during retrieval suppression can influence memory representations of motor actions, by not only reducing their accessibility but also by affecting their execution, once retrieved.
Topics: Humans; Mental Recall; Cues; Reaction Time; Movement
PubMed: 36191357
DOI: 10.1016/j.cognition.2022.105292 -
Proceedings of the National Academy of... Feb 2022Humans remember less and less of what was encoded as more and more time passes. Selective retrieval can interrupt such time-dependent forgetting, enhancing recall not...
Humans remember less and less of what was encoded as more and more time passes. Selective retrieval can interrupt such time-dependent forgetting, enhancing recall not only of the retrieved but also of the nonretrieved information. The recall enhancement has been attributed to context retrieval and the idea that selective retrieval reactivates the retrieved item's temporal context during study, which can facilitate recall of other items that had a similar context at study. However, it is unclear whether context retrieval induces a transient discontinuity in the stream of temporal context only, or a more permanent updating of context that would entail a lasting interruption of time-dependent forgetting. In three experiments, we analyzed time-dependent forgetting of encoded information right after study and after time-lagged selective retrieval. Selective retrieval boosted recall of the nonretrieved information up to the levels observed directly after study. Intriguingly, it also created a restart of time-dependent forgetting that made forgetting after retrieval indistinguishable from forgetting after study and thus induced a reset of the recall process. The results suggest that selective retrieval can revive forgotten memories and cause lasting recall enhancement, effects likely mediated by context retrieval and a permanent updating of temporal context.
Topics: Female; Germany; Humans; Male; Memory; Memory, Episodic; Memory, Long-Term; Mental Recall; Young Adult
PubMed: 35165194
DOI: 10.1073/pnas.2114377119 -
Psychonomic Bulletin & Review Jun 2018A hallmark feature of episodic memory is that of "mental time travel," whereby an individual feels they have returned to a prior moment in time. Cognitive and behavioral... (Review)
Review
A hallmark feature of episodic memory is that of "mental time travel," whereby an individual feels they have returned to a prior moment in time. Cognitive and behavioral neuroscience methods have revealed a neurobiological counterpart: Successful retrieval often is associated with reactivation of a prior brain state. We review the emerging literature on memory reactivation and recapitulation, and we describe evidence for the effects of emotion on these processes. Based on this review, we propose a new model: Negative Emotional Valence Enhances Recapitulation (NEVER). This model diverges from existing models of emotional memory in three key ways. First, it underscores the effects of emotion during retrieval. Second, it stresses the importance of sensory processing to emotional memory. Third, it emphasizes how emotional valence - whether an event is negative or positive - affects the way that information is remembered. The model specifically proposes that, as compared to positive events, negative events both trigger increased encoding of sensory detail and elicit a closer resemblance between the sensory encoding signature and the sensory retrieval signature. The model also proposes that negative valence enhances the reactivation and storage of sensory details over offline periods, leading to a greater divergence between the sensory recapitulation of negative and positive memories over time. Importantly, the model proposes that these valence-based differences occur even when events are equated for arousal, thus rendering an exclusively arousal-based theory of emotional memory insufficient. We conclude by discussing implications of the model and suggesting directions for future research to test the tenets of the model.
Topics: Emotions; Humans; Memory, Episodic; Mental Recall; Models, Psychological
PubMed: 28695528
DOI: 10.3758/s13423-017-1313-9