The Experts below are selected from a list of 85914 Experts worldwide ranked by ideXlab platform
Eric R. Kandel - One of the best experts on this subject based on the ideXlab platform.
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Synapses and Memory Storage
Cold Spring Harbor Perspectives in Biology, 2012Co-Authors: Mark Mayford, Steven A Siegelbaum, Eric R. KandelAbstract:The synapse is the functional unit of the brain. During the last several decades we have acquired a great deal of information on its structure, molecular components, and physiological function. It is clear that synapses are morphologically and molecularly diverse and that this diversity is recruited to different functions. One of the most intriguing findings is that the size of the synaptic response in not invariant, but can be altered by a variety of homo- and heterosynaptic factors such as past patterns of use or modulatory neurotransmitters. Perhaps the most difficult challenge in neuroscience is to design experiments that reveal how these basic building blocks of the brain are put together and how they are regulated to mediate the information flow through neural circuits that is necessary to produce complex behaviors and store memories. In this review we will focus on studies that attempt to uncover the role of synaptic plasticity in the regulation of whole-animal behavior by learning and Memory.
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synaptic remodeling synaptic growth and the Storage of long term Memory in aplysia
Progress in Brain Research, 2008Co-Authors: Craig H Bailey, Eric R. KandelAbstract:Synaptic remodeling and synaptic growth accompany various forms of long-term Memory. Storage of the long-term Memory for sensitization of the gill-withdrawal reflex in Aplysia has been extensively studied in this respect and is associated with the growth of new synapses by the sensory neurons onto their postsynaptic target neurons. Recent time-lapse imaging studies of living sensory-to-motor neuron synapses in culture have monitored both functional and structural changes simultaneously so as to follow remodeling and growth at the same specific synaptic connections continuously over time and to examine the functional contribution of these learning-related structural changes to the different time-dependent phases of Memory Storage. Insights provided by these studies suggest the synaptic differentiation and growth induced by learning in the mature nervous system are highly dynamic and often rapid processes that can recruit both molecules and mechanisms used for de novo synapse formation during development.
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molecular mechanisms of Memory Storage in aplysia
The Biological Bulletin, 2006Co-Authors: Robert D Hawkins, Eric R. Kandel, Craig H BaileyAbstract:Cellular studies of implicit and explicit Memory suggest that experience-dependent modulation of synaptic strength and structure is a fundamental mechanism by which these memories are encoded, processed, and stored within the brain. In this review, we focus on recent advances in our understanding of the molecular mechanisms that underlie short-term, intermediate-term, and long-term forms of implicit Memory in the marine invertebrate Aplysia cali- fornica, and consider how the conservation of common elements in each form may contribute to the different tem- poral phases of Memory Storage.
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Memory suppressor genes inhibitory constraints on the Storage of long term Memory
Science, 1998Co-Authors: Ted Abel, Dusan Bartsch, Kelsey C Martin, Eric R. KandelAbstract:Synaptic plasticity, the ability of neurons to alter the strength of their synaptic connections with activity and experience, is thought to play a critical role in Memory Storage. Molecular studies of gene expression during long-lasting synaptic plasticity related to Memory Storage initially focused on the identification of positive regulators. More recent work has revealed that the establishment of long-lasting synaptic plasticity and long-term Memory also requires the removal of inhibitory constraints. By analogy to tumor supressor genes, which restrain cell proliferation, we propose that these inhibitory constraints on Memory Storage, which restrain synapse growth, be termed Memory suppressor genes.
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toward a molecular definition of long term Memory Storage
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Craig H Bailey, Dusan Bartsch, Eric R. KandelAbstract:The Storage of long-term Memory is associated with a cellular program of gene expression, altered protein synthesis, and the growth of new synaptic connections. Recent studies of a variety of Memory processes, ranging in complexity from those produced by simple forms of implicit learning in invertebrates to those produced by more complex forms of explicit learning in mammals, suggest that part of the molecular switch required for consolidation of long-term Memory is the activation of a cAMP-inducible cascade of genes and the recruitment of cAMP response element binding protein-related transcription factors. This conservation of steps in the mechanisms for learning-related synaptic plasticity suggests the possibility of a molecular biology of cognition.
Nesha S Burghardt - One of the best experts on this subject based on the ideXlab platform.
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persistent increases of pkmζ in Memory activated neurons trace ltp maintenance during spatial long term Memory Storage
European Journal of Neuroscience, 2021Co-Authors: Changchi Hsieh, Panayiotis Tsokas, Alejandro Grauperales, Edith Lesburgueres, Joseph Bukai, Kunal Khanna, Joelle Chorny, Ain Chung, Claudia Jou, Nesha S BurghardtAbstract:PKMζ is an autonomously active PKC isoform crucial for the maintenance of synaptic long-term potentiation (LTP) and long-term Memory. Unlike other kinases that are transiently stimulated by second messengers, PKMζ is persistently activated through sustained increases in protein expression of the kinase. Therefore, visualizing increases in PKMζ expression during long-term Memory Storage might reveal the sites of its persistent action and thus the location of Memory-associated LTP maintenance in the brain. Using quantitative immunohistochemistry validated by the lack of staining in PKMζ-null mice, we examined the amount and distribution of PKMζ in subregions of the hippocampal formation of wild-type mice during LTP maintenance and spatial long-term Memory Storage. During LTP maintenance in hippocampal slices, PKMζ increases in the pyramidal cell body and stimulated dendritic layers of CA1 for at least 2 hr. During spatial Memory Storage, PKMζ increases in CA1 pyramidal cells for at least 1 month, paralleling the persistence of the Memory. During the initial expression of the Memory, we tagged principal cells with immediate-early gene Arc promoter-driven transcription of fluorescent proteins. The subset of Memory-tagged CA1 cells selectively increases expression of PKMζ during Memory Storage, and the increase persists in dendritic compartments within stratum radiatum for 1 month, indicating long-term Storage of information in the CA3-to-CA1 pathway. We conclude that persistent increases in PKMζ trace the molecular mechanism of LTP maintenance and thus the sites of information Storage within brain circuitry during long-term Memory.
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persistent increases of pkmζ in Memory activated neurons trace ltp maintenance during spatial long term Memory Storage
bioRxiv, 2021Co-Authors: Changchi Hsieh, Panayiotis Tsokas, Alejandro Grauperales, Edith Lesburgueres, Joseph Bukai, Kunal Khanna, Joelle Chorny, Ain Chung, Claudia Jou, Nesha S BurghardtAbstract:PKMζ is an autonomously active PKC isoform crucial for the maintenance of synaptic long-term potentiation (LTP) and long-term Memory. Unlike other protein kinases that are transiently stimulated by second messengers, PKMζ is persistently activated through sustained increases in kinase protein expression. Therefore, visualizing increases in PKMζ expression during long-term Memory Storage might reveal the sites of its persistent action and thus the location of Memory-associated LTP maintenance in the brain. Using quantitative immunohistochemistry validated by the lack of staining in PKMζ-null mice, we examined the amount and distribution of PKMζ in subregions of the hippocampal formation of wild-type mice during LTP maintenance and spatial long-term Memory Storage. During LTP maintenance in hippocampal slices, PKMζ increases in the pyramidal cell body and stimulated dendritic layers of CA1 for at least 2 h. During spatial Memory Storage, PKMζ increases in CA1 pyramidal cells for at least 1 month, paralleling the persistence of the Memory. The subset of CA1 pyramidal cells that are tagged by immediate early gene Arc-driven transcription of fluorescent proteins, whose expression increases during initial Memory formation, also expresses the persistent increase of PKMζ during Memory Storage. In the Memory-tagged cells, the increased PKMζ expression persists in dendritic compartments within stratum radiatum for 1 month, indicating the long-term Storage of information in the CA3-to-CA1 pathway during remote spatial Memory. We conclude that persistent increases in PKMζ trace the molecular mechanism of LTP maintenance and thus the sites of information Storage within brain circuitry during long-term Memory.
Tei Wei Kuo - One of the best experts on this subject based on the ideXlab platform.
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an efficient management scheme for large scale flash Memory Storage systems
ACM Symposium on Applied Computing, 2004Co-Authors: Li-pin Chang, Tei Wei KuoAbstract:Flash Memory is among the top choices for Storage media in ubiquitous computing. With a strong demand of high-capacity Storage devices, the usages of flash Memory quickly grow beyond their original designs. The very distinct characteristics of flash Memory introduce serious challenges to engineers in resolving the quick degradation of system performance and the huge demand of main-Memory space for flash-Memory management when high-capacity flash Memory is considered. Although some brute-force solutions could be taken, such as the enlarging of management granularity for flash Memory, we showed that little advantage is received when system performance is considered. This paper proposes a flexible management scheme for large-scale flash-Memory Storage systems. The objective is to efficiently manage high-capacity flash-Memory Storage systems based on the behaviors of realistic access patterns. The proposed scheme could significantly reduce the main-Memory usages without noticeable performance degradation.
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Real-Time Garbage Collection for Flash-Memory Storage Systems of Real-Time Embedded Systems
ACM Transactions on Embedded Computing Systems, 2004Co-Authors: Li-pin Chang, Tei Wei Kuo, Shi Wu LoAbstract:Flash-Memory technology is becoming critical in building embedded systems applications be- cause of its shock-resistant, power economic, and nonvolatile nature. With the recent technology breakthroughs in both capacity and reliability, flash-Memory Storage systems are now very pop- ular in many types of embedded systems. However, because flash Memory is a write-once and bulk-erase medium, we need a translation layer and a garbage-collection mechanism to provide applications a transparent Storage service. In the past work, various techniques were introduced to improve the garbage-collection mechanism. These techniques aimed at both performance and en- durance issues, but they all failed in providing applications a guaranteed performance. Inthis paper, we propose a real-time garbage-collection mechanism, which provides a guaranteed performance, for hard real-time systems. On the other hand, the proposed mechanism supports non-real-time tasks so that the potential bandwidth of the Storage system can be fully utilized. A wear-leveling method, which is executed as a non-real-time service, is presented to resolve the endurance prob- lem of flash Memory. The capability of the proposed mechanism is demonstrated by a series of experiments over our system prototype.
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an efficient b tree layer for flash Memory Storage systems
Embedded and Real-Time Computing Systems and Applications, 2003Co-Authors: Li-pin Chang, Tei Wei KuoAbstract:With a significant growth of the markets for consumer electronics and various embedded systems, flash Memory is now an economic solution for Storage systems design. For index structures which require intensively fine-grained updates/modifications, block-oriented access over flash Memory could introduce a significant number of redundant writes. It might not only severely degrade the overall performance but also damage the reliability of flash Memory. In this paper, we propose a very different approach which could efficiently handle fine-grained updates/modifications caused by B-Tree index access over flash Memory. The implementation is done directly over the flash translation layer (FTL) such that no modifications to existing application systems are needed. We demonstrate that the proposed methodology could significantly improve the system performance and, at the same time, reduce the overheads of flash-Memory management and the energy dissipation, when index structures are adopted over flash Memory.
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a dynamic voltage adjustment mechanism in reducing the power consumption of flash Memory for portable devices
International Conference on Consumer Electronics, 2001Co-Authors: Li-pin Chang, Tei Wei KuoAbstract:A dynamic-voltage-adjustment method is proposed to reduce the power consumption of a flash Memory Storage system, depending on the system workload. The usefulness of the proposed method is demonstrated by a series of experiments with very encouraging results.
Jorge H Medina - One of the best experts on this subject based on the ideXlab platform.
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Evidence of Maintenance Tagging in the Hippocampus for the Persistence of Long-Lasting Memory Storage
Hindawi Limited, 2015Co-Authors: Micol Tomaiuolo, Cynthia Katche, Haydee Viola, Jorge H MedinaAbstract:The synaptic tagging and capture (STC) hypothesis provides a compelling explanation for synaptic specificity and facilitation of long-term potentiation. Its implication on long-term Memory (LTM) formation led to postulate the behavioral tagging mechanism. Here we show that a maintenance tagging process may operate in the hippocampus late after acquisition for the persistence of long-lasting Memory Storage. The proposed maintenance tagging has several characteristics: (1) the tag is transient and time-dependent; (2) it sets in a late critical time window after an aversive training which induces a short-lasting LTM; (3) exposing rats to a novel environment specifically within this tag time window enables the consolidation to a long-lasting LTM; (4) a familiar environment exploration was not effective; (5) the effect of novelty on the promotion of Memory persistence requires dopamine D1/D5 receptors and Arc expression in the dorsal hippocampus. The present results can be explained by a broader version of the behavioral tagging hypothesis and highlight the idea that the durability of a Memory trace depends either on late tag mechanisms induced by a training session or on events experienced close in time to this tag
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delayed wave of c fos expression in the dorsal hippocampus involved specifically in persistence of long term Memory Storage
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Cynthia Katche, Pedro Bekinschtein, Leandro Slipczuk, Andrea Paula Goldin, Ivan Izquierdo, Martin Cammarota, Jorge H MedinaAbstract:Memory formation is a temporally graded process during which transcription and translation steps are required in the first hours after acquisition. Although persistence is a key characteristic of Memory Storage, its mechanisms are scarcely characterized. Here, we show that long-lasting but not short-lived inhibitory avoidance long-term Memory is associated with a delayed expression of c-Fos in the hippocampus. Importantly, this late wave of c-Fos is necessary for maintenance of inhibitory avoidance long-term Storage. Moreover, inhibition of transcription in the dorsal hippocampus 24 h after training hinders persistence but not formation of long-term Storage. These findings indicate that a delayed phase of transcription is essential for maintenance of a hippocampus-dependent Memory trace. Our results support the hypothesis that recurrent rounds of consolidation-like events take place late after learning in the dorsal hippocampus to maintain memories.
Craig H Bailey - One of the best experts on this subject based on the ideXlab platform.
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synaptic remodeling synaptic growth and the Storage of long term Memory in aplysia
Progress in Brain Research, 2008Co-Authors: Craig H Bailey, Eric R. KandelAbstract:Synaptic remodeling and synaptic growth accompany various forms of long-term Memory. Storage of the long-term Memory for sensitization of the gill-withdrawal reflex in Aplysia has been extensively studied in this respect and is associated with the growth of new synapses by the sensory neurons onto their postsynaptic target neurons. Recent time-lapse imaging studies of living sensory-to-motor neuron synapses in culture have monitored both functional and structural changes simultaneously so as to follow remodeling and growth at the same specific synaptic connections continuously over time and to examine the functional contribution of these learning-related structural changes to the different time-dependent phases of Memory Storage. Insights provided by these studies suggest the synaptic differentiation and growth induced by learning in the mature nervous system are highly dynamic and often rapid processes that can recruit both molecules and mechanisms used for de novo synapse formation during development.
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molecular mechanisms of Memory Storage in aplysia
The Biological Bulletin, 2006Co-Authors: Robert D Hawkins, Eric R. Kandel, Craig H BaileyAbstract:Cellular studies of implicit and explicit Memory suggest that experience-dependent modulation of synaptic strength and structure is a fundamental mechanism by which these memories are encoded, processed, and stored within the brain. In this review, we focus on recent advances in our understanding of the molecular mechanisms that underlie short-term, intermediate-term, and long-term forms of implicit Memory in the marine invertebrate Aplysia cali- fornica, and consider how the conservation of common elements in each form may contribute to the different tem- poral phases of Memory Storage.
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toward a molecular definition of long term Memory Storage
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Craig H Bailey, Dusan Bartsch, Eric R. KandelAbstract:The Storage of long-term Memory is associated with a cellular program of gene expression, altered protein synthesis, and the growth of new synaptic connections. Recent studies of a variety of Memory processes, ranging in complexity from those produced by simple forms of implicit learning in invertebrates to those produced by more complex forms of explicit learning in mammals, suggest that part of the molecular switch required for consolidation of long-term Memory is the activation of a cAMP-inducible cascade of genes and the recruitment of cAMP response element binding protein-related transcription factors. This conservation of steps in the mechanisms for learning-related synaptic plasticity suggests the possibility of a molecular biology of cognition.
