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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 -
The Behavioral and Brain Sciences Nov 2023We raise two points about cues, which complicate Barzykowski and Moulin's attempt at a unified model of memory retrieval. First, cues operate differently in voluntary...
We raise two points about cues, which complicate Barzykowski and Moulin's attempt at a unified model of memory retrieval. First, cues operate differently in voluntary and involuntary contexts. Second, voluntary and involuntary memory can be interconnected, as in cases of chaining.
Topics: Humans; Cues; Mental Recall; Memory
PubMed: 37961813
DOI: 10.1017/S0140525X23000122 -
The Lancet. Neurology May 2024
Topics: Humans; Mental Recall; Attention
PubMed: 38636527
DOI: 10.1016/S1474-4422(24)00137-6 -
Cell Reports Aug 2023Long-term memories are stored as configurations of neuronal ensembles, termed engrams. Although investigation of engram cell properties and functionality in memory...
Long-term memories are stored as configurations of neuronal ensembles, termed engrams. Although investigation of engram cell properties and functionality in memory recall has been extensive, less is known about how engram cells are affected by forgetting. We describe a form of interference-based forgetting using an object memory behavioral paradigm. By using activity-dependent cell labeling, we show that although retroactive interference results in decreased engram cell reactivation during recall trials, optogenetic stimulation of the labeled engram cells is sufficient to induce memory retrieval. Forgotten engrams may be reinstated via the presentation of similar or related environmental information. Furthermore, we demonstrate that engram activity is necessary for interference to occur. Taken together, these findings indicate that retroactive interference modules engram expression in a manner that is both reversible and updatable. Inference may constitute a form of adaptive forgetting where, in everyday life, new perceptual and environmental inputs modulate the natural forgetting process.
Topics: Memory; Memory, Long-Term; Mental Recall; Optogenetics
PubMed: 37590145
DOI: 10.1016/j.celrep.2023.112999 -
Current Opinion in Psychology Feb 2024Memory often declines with age, but older adults can off-set memory challenges by selectively remembering important information. When encountering large amounts of... (Review)
Review
Memory often declines with age, but older adults can off-set memory challenges by selectively remembering important information. When encountering large amounts of information and knowing that memory is limited, older adults may choose to focus on what is most important and forget less relevant details. Prioritizing what to remember becomes essential when memory is limited, and influences what information can be off-loaded. While forgetting can be frustrating and consequential, a lifetime of these experiences may help older adults learn to focus on strategically remembering important information and life events. Curiosity and emotion may also guide what older adults remember, such that selective remembering can be an adaptive way to use memory efficiently in older age.
Topics: Humans; Aged; Memory; Aging; Mental Recall; Emotions
PubMed: 38043146
DOI: 10.1016/j.copsyc.2023.101744 -
Current Biology : CB Sep 2023Gerry Rubin remembers Michael Ashburner, one of the fathers of contemporary Drosophila genetics and genomics.
Gerry Rubin remembers Michael Ashburner, one of the fathers of contemporary Drosophila genetics and genomics.
Topics: Animals; Drosophila; Genomics; Heteroptera; Mental Recall
PubMed: 37619564
DOI: 10.1016/j.cub.2023.08.029 -
Nature Communications Jul 2023Dysregulated fear reactions can result from maladaptive processing of trauma-related memories. In post-traumatic stress disorder (PTSD) and other psychiatric disorders,...
Dysregulated fear reactions can result from maladaptive processing of trauma-related memories. In post-traumatic stress disorder (PTSD) and other psychiatric disorders, dysfunctional extinction learning prevents discretization of trauma-related memory engrams and generalizes fear responses. Although PTSD may be viewed as a memory-based disorder, no approved treatments target pathological fear memory processing. Hippocampal sharp wave-ripples (SWRs) and concurrent neocortical oscillations are scaffolds to consolidate contextual memory, but their role during fear processing remains poorly understood. Here, we show that closed-loop, SWR triggered neuromodulation of the medial forebrain bundle (MFB) can enhance fear extinction consolidation in male rats. The modified fear memories became resistant to induced recall (i.e., 'renewal' and 'reinstatement') and did not reemerge spontaneously. These effects were mediated by D2 receptor signaling-induced synaptic remodeling in the basolateral amygdala. Our results demonstrate that SWR-triggered closed-loop stimulation of the MFB reward system enhances extinction of fearful memories and reducing fear expression across different contexts and preventing excessive and persistent fear responses. These findings highlight the potential of neuromodulation to augment extinction learning and provide a new avenue to develop treatments for anxiety disorders.
Topics: Rats; Male; Animals; Fear; Extinction, Psychological; Memory; Mental Recall; Basolateral Nuclear Complex; Stress Disorders, Post-Traumatic; Memory Disorders
PubMed: 37407557
DOI: 10.1038/s41467-023-39546-7 -
Wiley Interdisciplinary Reviews.... 2023Memory researchers and theorists have long advanced the idea that the manner in which information is retrieved is critical. The way retrieval unfolds provides critical... (Review)
Review
Memory researchers and theorists have long advanced the idea that the manner in which information is retrieved is critical. The way retrieval unfolds provides critical insights into how memories are organized and accessed-an important aspect of memory missed by focusing only on quantity. Cognitive studies of memory in social contexts, deploying the collaborative memory paradigm, have also noted the importance of such retrieval organization. Such memory studies often focus on how relative to "groups" that never collaborated, former members of collaborating groups recall more of the same material (collective memory) and they do so in a more synchronized fashion (collective retrieval organization). In this review, we leverage the diverse methodological and quantitative toolkits that have traditionally targeted individual retrieval to highlight the ways in which this social memory research has examined collective memory and collective retrieval organization. To that end, we consider how the collaborative memory paradigm has integrated methods, such as free recall, that afford rich assessments of retrieval organization. Likewise, we consider the application of metrics that characterize organization patterns in different contexts. With this background in mind, we discuss the important theoretical and broader implications of research on collective memory and collective retrieval organization. This article is categorized under: Psychology > Memory.
Topics: Humans; Cooperative Behavior; Mental Recall
PubMed: 36635944
DOI: 10.1002/wcs.1641 -
Current Biology : CB Sep 2023Remote memories play an important role in how we perceive the world, and they are rooted throughout the brain in "engrams": ensembles of cells that are formed during...
Remote memories play an important role in how we perceive the world, and they are rooted throughout the brain in "engrams": ensembles of cells that are formed during acquisition. Upon their reactivation, a specific memory can be recalled. Many studies have focused on the ensembles in CA1 of the hippocampus and the anterior cingulate cortex (ACC). However, the evolution of these components during systems' consolidation has not yet been comprehensively addressed. By applying transgenic approaches for ensemble identification, CLARITY, retro-AAV, and pseudo-rabies virus for circuit mapping, and chemogenetics for functional interrogation, we addressed the dynamics of recent and remote CA1 ensembles. We expected both stability (as they represent the same memory) and maturation (over time). Indeed, we found that CA1 engrams remain stable between recent and remote recalls, and the inhibition of engrams for recent recall during remote recall functionally impairs memory. We also found that new cells in the remote recall engram in the CA1 are not added randomly during maturation but differ according to their connections. First, we show in two ways that the anterograde CA1 → ACC engram cell projection grows larger. Finally, in the retrograde projections, the ACC reduces input to CA1 engram cells, whereas input from the entorhinal cortex and paraventricular nucleus of the thalamus increases. Our results shine fresh light on systems' consolidation by providing a deeper understanding of engram stability and maturation in the transition from recent to remote memory.
Topics: Hippocampus; Memory, Long-Term; Mental Recall; Entorhinal Cortex; Gyrus Cinguli
PubMed: 37586373
DOI: 10.1016/j.cub.2023.07.042 -
Nature Neuroscience Mar 2024Episodic memories are encoded by experience-activated neuronal ensembles that remain necessary and sufficient for recall. However, the temporal evolution of memory...
Episodic memories are encoded by experience-activated neuronal ensembles that remain necessary and sufficient for recall. However, the temporal evolution of memory engrams after initial encoding is unclear. In this study, we employed computational and experimental approaches to examine how the neural composition and selectivity of engrams change with memory consolidation. Our spiking neural network model yielded testable predictions: memories transition from unselective to selective as neurons drop out of and drop into engrams; inhibitory activity during recall is essential for memory selectivity; and inhibitory synaptic plasticity during memory consolidation is critical for engrams to become selective. Using activity-dependent labeling, longitudinal calcium imaging and a combination of optogenetic and chemogenetic manipulations in mouse dentate gyrus, we conducted contextual fear conditioning experiments that supported our model's predictions. Our results reveal that memory engrams are dynamic and that changes in engram composition mediated by inhibitory plasticity are crucial for the emergence of memory selectivity.
Topics: Mice; Animals; Memory Consolidation; Mental Recall; Neurons; Fear; Memory, Episodic
PubMed: 38243089
DOI: 10.1038/s41593-023-01551-w