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Current Psychiatry Reports Aug 2018I summarize recent developments in understanding the phenomenology of memory in PTSD, describe the most prominent theoretical models, and outline new forms of treatment... (Review)
Review
PURPOSE OF REVIEW
I summarize recent developments in understanding the phenomenology of memory in PTSD, describe the most prominent theoretical models, and outline new forms of treatment aimed at modifying the traumatic memory.
RECENT FINDINGS
Intrusive memories that have the quality of being relived in the present have been highlighted in ICD-11. Debate over whether trauma memories are disorganized has led to a distinction between global narratives that are usually well rehearsed and episodic memories of the most frightening moments when disruptions and fragmentation may occur. Attempts to prevent the initial consolidation of trauma memories have promise in prevention but face practical difficulties. Theoretical developments have led to a number of promising treatments for established PTSD including pre-retrieval propranolol and imagery rescripting. Research has suggested real possibilities to improve the prevention and treatment of PTSD by modifying trauma recall even though the theoretical basis for these interventions remains controversial.
Topics: Fear; Humans; Memory, Episodic; Mental Recall; Stress Disorders, Post-Traumatic
PubMed: 30155780
DOI: 10.1007/s11920-018-0950-7 -
Neuron Oct 2015Memory consolidation refers to the transformation over time of experience-dependent internal representations and their neurobiological underpinnings. The process is... (Review)
Review
Memory consolidation refers to the transformation over time of experience-dependent internal representations and their neurobiological underpinnings. The process is assumed to be embodied in synaptic and cellular modifications at brain circuits in which the memory is initially encoded and to proceed by recurrent reactivations, both during wakefulness and during sleep, culminating in the distribution of information to additional locales and integration of new information into existing knowledge. We present snapshots of our current knowledge and gaps in knowledge concerning the progress of consolidation over time and the cognitive architecture that supports it and shapes our long-term memories.
Topics: Brain; Humans; Memory; Memory Consolidation; Memory, Long-Term; Neural Pathways; Sleep; Wakefulness
PubMed: 26447570
DOI: 10.1016/j.neuron.2015.09.004 -
Trends in Cognitive Sciences Aug 2017Current interpretations of hippocampal memory function are blind to the fact that viewing behaviors are pervasive and complicate the relationships among perception,... (Review)
Review
Current interpretations of hippocampal memory function are blind to the fact that viewing behaviors are pervasive and complicate the relationships among perception, behavior, memory, and brain activity. For example, hippocampal activity and associative memory demands increase with stimulus complexity. Stimulus complexity also strongly modulates viewing. Associative processing and viewing thus are often confounded, rendering interpretation of hippocampal activity ambiguous. Similar considerations challenge many accounts of hippocampal function. To explain relationships between memory and viewing, we propose that the hippocampus supports the online memory demands necessary to guide visual exploration. The hippocampus thus orchestrates memory-guided exploration that unfolds over time to build coherent memories. This new perspective on hippocampal function harmonizes with the fact that memory formation and exploratory viewing are tightly intertwined.
Topics: Hippocampus; Humans; Magnetic Resonance Imaging; Memory
PubMed: 28625353
DOI: 10.1016/j.tics.2017.05.008 -
Behavioral Neuroscience Dec 2011Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation... (Review)
Review
Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala that regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall, and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions.
Topics: Amygdala; Animals; Glucocorticoids; Humans; Memory; Memory, Short-Term; Mental Recall; Nerve Net; Norepinephrine; Retention, Psychology; Signal Transduction
PubMed: 22122145
DOI: 10.1037/a0026187 -
Current Neurology and Neuroscience... Feb 2014Sleep benefits memory consolidation. Previous theoretical accounts have proposed a differential role of slow-wave sleep (SWS), rapid-eye-movement (REM) sleep, and stage... (Review)
Review
Sleep benefits memory consolidation. Previous theoretical accounts have proposed a differential role of slow-wave sleep (SWS), rapid-eye-movement (REM) sleep, and stage N2 sleep for different types of memories. For example the dual process hypothesis proposes that SWS is beneficial for declarative memories, whereas REM sleep is important for consolidation of non-declarative, procedural and emotional memories. In fact, numerous recent studies do provide further support for the crucial role of SWS (or non-REM sleep) in declarative memory consolidation. However, recent evidence for the benefit of REM sleep for non-declarative memories is rather scarce. In contrast, several recent studies have related consolidation of procedural memories (and some also emotional memories) to SWS (or non-REM sleep)-dependent consolidation processes. We will review this recent evidence, and propose future research questions to advance our understanding of the role of different sleep stages for memory consolidation.
Topics: Animals; Humans; Memory; Sleep Stages; Sleep, REM
PubMed: 24395522
DOI: 10.1007/s11910-013-0430-8 -
Cognitive and Behavioral Neurology :... Dec 2022We suggest that there is confusion between why consciousness developed and what additional functions, through continued evolution, it has co-opted. Consider episodic...
We suggest that there is confusion between why consciousness developed and what additional functions, through continued evolution, it has co-opted. Consider episodic memory. If we believe that episodic memory evolved solely to accurately represent past events, it seems like a terrible system-prone to forgetting and false memories. However, if we believe that episodic memory developed to flexibly and creatively combine and rearrange memories of prior events in order to plan for the future, then it is quite a good system. We argue that consciousness originally developed as part of the episodic memory system-quite likely the part needed to accomplish that flexible recombining of information. We posit further that consciousness was subsequently co-opted to produce other functions that are not directly relevant to memory per se, such as problem-solving, abstract thinking, and language. We suggest that this theory is compatible with many phenomena, such as the slow speed and the after-the-fact order of consciousness, that cannot be explained well by other theories. We believe that our theory may have profound implications for understanding intentional action and consciousness in general. Moreover, we suggest that episodic memory and its associated memory systems of sensory, working, and semantic memory as a whole ought to be considered together as the conscious memory system in that they, together, give rise to the phenomenon of consciousness. Lastly, we suggest that the cerebral cortex is the part of the brain that makes consciousness possible, and that every cortical region contributes to this conscious memory system.
Topics: Humans; Consciousness; Memory; Brain; Cognition; Memory, Episodic
PubMed: 36178498
DOI: 10.1097/WNN.0000000000000319 -
Trends in Cognitive Sciences Jul 2017The reactivation of a stored memory in the brain can make the memory transiently labile. During the time it takes for the memory to restabilize (reconsolidate) the... (Review)
Review
The reactivation of a stored memory in the brain can make the memory transiently labile. During the time it takes for the memory to restabilize (reconsolidate) the memory can either be reduced by an amnesic agent or enhanced by memory enhancers. The change in memory expression is related to changes in the brain correlates of long-term memory. Many have suggested that such retrieval-induced plasticity is ideally placed to enable memories to be updated with new information. This hypothesis has been tested experimentally, with a translational perspective, by attempts to update maladaptive memories to reduce their problematic impact. We review here progress on reconsolidation updating studies, highlighting their translational exploitation and addressing recent challenges to the reconsolidation field.
Topics: Brain; Humans; Memory; Memory Consolidation; Memory, Long-Term
PubMed: 28495311
DOI: 10.1016/j.tics.2017.04.006 -
Psychopharmacology Jan 2019Post-traumatic stress disorder (PTSD) is a psychiatric disorder associated with memories of traumatic experiences. Conditioned fear memory, a representative model of... (Review)
Review
Post-traumatic stress disorder (PTSD) is a psychiatric disorder associated with memories of traumatic experiences. Conditioned fear memory, a representative model of traumatic memories, is observed across species from lower to higher animals, including humans. Numerous studies have investigated the mechanisms of conditioned fear memory and have led to the identification of the underlying processes involved in fear memory regulation, including cellular and systems consolidation of fear conditioning, destabilization/reconsolidation and extinction after fear memory retrieval, and forgetting of fear memory. These studies suggested that mechanisms for fear memory regulation are shared by humans and other higher animals. Additionally, rodent studies have identified the mechanisms of fear memory at the molecular, cellular, and circuit levels. Findings from these studies in rodents have been applied to facilitate the development and improvement of PTSD intervention. For instance, reconsolidation and extinction of fear memories have been applied for PTSD treatment to improve prolonged exposure (PE) therapy, an effective psychotherapy for PTSD. Combination of medications weakening retrieved traumatic memory (e.g., by facilitating both destabilization and extinction) with PE therapy may contribute to improvement of PTSD. Interestingly, a recent study in mice identified forgetting of fear memory as another potential therapeutic target for PTSD. A better understanding of the mechanisms involved in fear memory processes is likely to facilitate the development of better treatments for PTSD. This review describes fear memory processes and their mechanisms and discusses the pros and cons of applying how this knowledge can be applied in the development of interventions for PTSD.
Topics: Animals; Extinction, Psychological; Fear; Humans; Implosive Therapy; Memory; Memory Consolidation; Stress Disorders, Post-Traumatic
PubMed: 30374892
DOI: 10.1007/s00213-018-5086-2 -
Behavioural Neurology 2020Patients with Alzheimer's Disease (AD) not only are suffering from amnesia but also are prone to memory distortions, such as experiencing detailed and vivid... (Review)
Review
Patients with Alzheimer's Disease (AD) not only are suffering from amnesia but also are prone to memory distortions, such as experiencing detailed and vivid recollections of episodic events that have never been encountered (i.e., false memories). To describe and explain these distortions, we offer a review to synthesize current knowledge on false memory in AD into a framework allowing for better understanding of the taxonomy and phenomenology of false memories and of the cognitive mechanisms that may underlie false memory formation in AD. According to this review, certain phenomenological characteristics of memories (e.g., high emotional load, high vividness, or high familiarity) result in misattributions in AD. More specifically, this review proposes that generalized decline in cognitive control and inhibition in AD may result in difficulties in suppressing irrelevant information during memory monitoring, especially when irrelevant (i.e., false) information is characterized by high emotion, vividness, or familiarity. This review also proposes that binding deficits in AD decrease the ability to retrieve relevant contextual details, leading to source monitoring errors and false memories. In short, this review depicts how phenomenological characteristics of memories and failures of monitoring during retrieval contribute to the occurrence of false memory in AD.
Topics: Alzheimer Disease; Amnesia; Humans; Inhibition, Psychological; Memory; Memory Disorders; Memory, Episodic; Mental Recall; Neuropsychological Tests
PubMed: 32148564
DOI: 10.1155/2020/5284504 -
Trends in Neurosciences Jan 2019Over the past half-century, we have gained significant insights into the molecular biology of long-term memory storage at the level of the synapse. In recent years, our... (Review)
Review
Over the past half-century, we have gained significant insights into the molecular biology of long-term memory storage at the level of the synapse. In recent years, our understanding of the cellular architecture supporting long-term memory traces has also substantially improved. However, the molecular biology of consolidation at the level of neuronal systems has been relatively neglected. In this opinion article, we first examine our current understanding of the cellular mechanisms of synaptic consolidation. We then outline areas requiring further investigation on how cellular changes contribute to systems consolidation. Finally, we highlight recent findings on the cellular architecture of memory traces in rodents and how the application of new technologies will expand our understanding of systems consolidation at the neural circuit level. In the coming years, this research focus will be critical for understanding the evolution of long-term memories and for enabling the development of novel therapeutics which embrace the dynamic nature of memories.
Topics: Animals; Humans; Memory; Memory, Long-Term; Models, Neurological; Neuronal Plasticity; Neurons; Synapses
PubMed: 30391015
DOI: 10.1016/j.tins.2018.10.005