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Larry R Squire - One of the best experts on this subject based on the ideXlab platform.
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declarative memory system Amnesia
Reference Module in Neuroscience and Biobehavioral Psychology#R##N#Learning and Memory: A Comprehensive Reference (Second Edition), 2017Co-Authors: Larry R Squire, Yael ShragerAbstract:Significant information about how memory is organized has come from the study of patients with memory disorders (Amnesia). Amnesia refers to difficulty in acquiring new declarative (conscious) knowledge and in remembering the recent past. This condition results from bilateral damage to the medial temporal lobe or the diencephalic midline. Declarative memory impairment can occur as a well-circumscribed disorder against a background of otherwise intact intellectual and cognitive functions. Older memories that have undergone a process of consolidation and reorganization are usually intact in amnesic patients and are stored in the neocortex independently of the medial temporal lobe. Amnesic patients retain the ability to learn nondeclaratively (unconsciously), as in the case of habits and skills for which memory is expressed through performance rather than remembrance.
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Amnesia declarative and nondeclarative memory
Reference Module in Neuroscience and Biobehavioral Psychology#R##N#Encyclopedia of Neuroscience, 2009Co-Authors: Larry R Squire, Peter J. Bayley, Christine N SmithAbstract:Amnesia refers to difficulty in acquiring new declarative (conscious) knowledge and in remembering the recent past. This condition results from bilateral damage to the medial temporal lobe or diencephalic midline. Memory impairment can occur as a well-circumscribed disorder against a background of otherwise intact intellectual and cognitive functions. Older memories that have undergone a process of consolidation and reorganization are usually intact in amnesic patients and are stored in the neocortex independently of the medial temporal lobe. Amnesic patients retain the ability to learn nondeclaratively (unconsciously), as in the case of habits and skills, in which memory is expressed through performance rather than recollection.
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anterograde Amnesia and temporally graded retrograde Amnesia for a nonspatial memory task after lesions of hippocampus and subiculum
The Journal of Neuroscience, 2002Co-Authors: Robert E Clark, Stuart M Zola, Nicola J Broadbent, Larry R SquireAbstract:We studied the importance of the hippocampus and subiculum for anterograde and retrograde memory in the rat using social transmission of food preference, a nonspatial memory task. Experiment 1 asked how long an acquired food preference could be remembered. In experiment 2, we determined the anterograde amnesic effects of large lesions of the hippocampus that included the subiculum. In experiment 3, large lesions of the hippocampus that included the subiculum were made 1, 10, or 30 d after learning to determine the nature and extent of retrograde Amnesia. Normal rats exhibited memory of the acquired food preference for at least 3 months after learning. Hippocampal lesions that included the subiculum produced marked anterograde Amnesia and a 1–30 d temporally graded retrograde Amnesia. The results show the importance of the hippocampus and related structures for nonspatial memory and also demonstrate the temporary role of these structures in long-term memory.
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impaired recognition memory on the doors and people test after damage limited to the hippocampal region
Hippocampus, 1999Co-Authors: Joseph R Manns, Larry R SquireAbstract:There have been conflicting reports about the importance of the hippocampal region for recognition memory. Vargha-Khadem et al. (1997) described three patients who became amnesic early in life as a result of damage apparently limited to the hippocampal region. One of these patients (Jon) performed normally on the recognition portion of the Doors and People Test but was severely impaired in recall. To compare adult-onset Amnesia directly with these early-onset cases, we tested six amnesic patients on the Doors and People Test. Three of the patients have damage thought to be limited to the hippocampal region. All six patients were markedly impaired on both the recall and recognition portions of the test. To account for the difference between our adult-onset cases and the early-onset case (Jon), we suggest that some compensation for Jon's injury occurred during development, either due to functional reorganization of cortex adjacent to the hippocampus or as the result of learned strategies. Hippocampus 1999;9:495–499. © 1999 Wiley-Liss, Inc.
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retrograde Amnesia for facts and events findings from four new cases
The Journal of Neuroscience, 1998Co-Authors: Jonathan M Reed, Larry R SquireAbstract:Two patients with presumed hippocampal formation lesions and two patients with more extensive temporal lobe damage, all of whom became amnesic in a known year, were given tests of anterograde and retrograde memory function. The two patients with hippocampal formation lesions had moderately severe anterograde Amnesia and limited retrograde Amnesia for facts and events that affected, at most, the decade preceding the onset of Amnesia. Content analysis could not distinguish the autobiographical recollections of the patients from the recollections of control subjects. The two patients with more extensive temporal lobe damage had severe anterograde Amnesia and extensive retrograde memory loss for both facts and events. The results suggest that whether retrograde Amnesia is temporally limited or very extensive depends on whether the damage is restricted to the hippocampal formation or also involves additional temporal cortex.
Stuart M Zola - One of the best experts on this subject based on the ideXlab platform.
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anterograde Amnesia and temporally graded retrograde Amnesia for a nonspatial memory task after lesions of hippocampus and subiculum
The Journal of Neuroscience, 2002Co-Authors: Robert E Clark, Stuart M Zola, Nicola J Broadbent, Larry R SquireAbstract:We studied the importance of the hippocampus and subiculum for anterograde and retrograde memory in the rat using social transmission of food preference, a nonspatial memory task. Experiment 1 asked how long an acquired food preference could be remembered. In experiment 2, we determined the anterograde amnesic effects of large lesions of the hippocampus that included the subiculum. In experiment 3, large lesions of the hippocampus that included the subiculum were made 1, 10, or 30 d after learning to determine the nature and extent of retrograde Amnesia. Normal rats exhibited memory of the acquired food preference for at least 3 months after learning. Hippocampal lesions that included the subiculum produced marked anterograde Amnesia and a 1–30 d temporally graded retrograde Amnesia. The results show the importance of the hippocampus and related structures for nonspatial memory and also demonstrate the temporary role of these structures in long-term memory.
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episodic memory semantic memory and Amnesia
Hippocampus, 1998Co-Authors: Larry R Squire, Stuart M ZolaAbstract:Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline diencephalic structures, predicts that amnesic patients with medial temporal lobe/diencephalic damage should be proportionately impaired in both episodic and semantic memory. An alternative view is that the capacity for semantic memory is spared, or partially spared, in Amnesia relative to episodic memory ability. This article reviews two kinds of relevant data: 1) case studies where Amnesia has occurred early in childhood, before much of an individual's semantic knowledge has been acquired, and 2) experimental studies with amnesic patients of fact and event learning, remembering and knowing, and remote memory. The data provide no compelling support for the view that episodic and semantic memory are affected differently in medial temporal lobe/diencephalic Amnesia. However, episodic and semantic memory may be dissociable in those amnesic patients who additionally have severe frontal lobe damage. Hippocampus 1998;8:205–211. Published 1998 Wiley-Liss, Inc.
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episodic memory semantic memory and Amnesia
Hippocampus, 1998Co-Authors: Larry R Squire, Stuart M ZolaAbstract:Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline diencephalic structures, predicts that amnesic patients with medial temporal lobe/diencephalic damage should be proportionately impaired in both episodic and semantic memory. An alternative view is that the capacity for semantic memory is spared, or partially spared, in Amnesia relative to episodic memory ability. This article reviews two kinds of relevant data: 1) case studies where Amnesia has occurred early in childhood, before much of an individual's semantic knowledge has been acquired, and 2) experimental studies with amnesic patients of fact and event learning, remembering and knowing, and remote memory. The data provide no compelling support for the view that episodic and semantic memory are affected differently in medial temporal lobe/diencephalic Amnesia. However, episodic and semantic memory may be dissociable in those amnesic patients who additionally have severe frontal lobe damage.
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three cases of enduring memory impairment after bilateral damage limited to the hippocampal formation
The Journal of Neuroscience, 1996Co-Authors: Nancy L Rempelclower, Stuart M Zola, Larry R Squire, David G AmaralAbstract:Patient RB (Human Amnesia and the medial temporal region: enduring memory impairment following a bilaterial lesion limited to field CA1 of the hippocampus, S. Zola-Morgan, L. R. Squire, and D. G. Amaral, 1986, J Neurosci 6:2950–2967) was the first reported case of human Amnesia in which detailed neuropsychological analyses and detailed postmortem neuropathological analyses demonstrated that damage limited to the hippocampal formation was sufficient to produce anterograde memory impairment. Neuropsychological and postmortem neuropathological findings are described here for three additional amnesic patients with bilateral damage limited to the hippocampal formation. Findings from these patients, taken together with the findings from patient RB and other amnesic patients, make three important points about memory. (1) Bilateral damage limited primarily to the CA1 region of the hippocampal formation is sufficient to produce moderately severe anterograde memory impairment. (2) Bilateral damage beyond the CA1 region, but still limited to the hippocampal formation, can produce more severe anterograde memory impairment. (3) Extensive, temporally graded retrograde Amnesia covering 15 years or more can occur after damage limited to the hippocampal formation. Findings from studies with experimental animals are consistent with the findings from amnesic patients. The present results substantiate the idea that severity of memory impairment is dependent on locus and extent of damage within the hippocampal formation and that damage to the hippocampal formation can cause temporally graded retrograde Amnesia.
Won Kyung Jeon - One of the best experts on this subject based on the ideXlab platform.
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terminalia chebula extract prevents scopolamine induced Amnesia via cholinergic modulation and anti oxidative effects in mice
BMC Complementary and Alternative Medicine, 2018Co-Authors: Minsoo Kim, Dong Young Lee, Jun Lee, Hyun Woo Kim, Sang Hyun Sung, Jungsoo Han, Won Kyung JeonAbstract:Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates Amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects. TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined. In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA. These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for Amnesia.
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Terminalia chebula extract prevents scopolamine-induced Amnesia via cholinergic modulation and anti-oxidative effects in mice
BMC, 2018Co-Authors: Minsoo Kim, Dong Young Lee, Jun Lee, Hyun Woo Kim, Sang Hyun Sung, Jungsoo Han, Won Kyung JeonAbstract:Abstract Background Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates Amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects. Methods TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined. Results In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA. Conclusion These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for Amnesia
Tangui Maurice - One of the best experts on this subject based on the ideXlab platform.
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differential involvement of the sigma1 σ1 receptor in the anti amnesic effect of neuroactive steroids as demonstrated using an in vivo antisense strategy in the mouse
British Journal of Pharmacology, 2001Co-Authors: Tangui Maurice, Vânly Phan, Alexandre Urani, Isabelle GuillemainAbstract:The sigma1 (σ1) receptor cDNA was cloned in several animal species. Molecular tools are now available to identify its endogenous effectors, such as neuroactive steroids, and to establish its precise physiological role. In particular, the σ1 receptor is involved in memory processes, as observed in pharmacological and pathological rodent models of Amnesia. In order to establish the involvement of σ1 receptors in memory, a 16-mer oligodeoxynucleotide antisense to the σ1 receptor cDNA (aODN), and its mismatched control (mODN) were prepared and centrally administered into the mouse brain. The anti-amnesic effects induced by the selective σ1 agonist PRE-084 and the steroid dehydroepiandrosterone (DHEA) sulphate or pregnenolone sulphate were examined in ODN-treated animals. The aODN treatment failed to affect the dissociation constant (Kd) but significantly decreased the number of σ1 sites (Bmax) labelled with [3H]-(+)-SKF-10,047 in the hippocampus and cortex. In these structures, the in vivo binding levels were also diminished, according to the dose and number of injections, as compared with control animals injected with saline or mODN. Cannulation and injections failed to affect the open-field behaviour of the animals. However, the anti-amnesic effects of PRE-084 and DHEA sulphate against the dizocilpine-induced impairments were blocked after aODN treatment in the short- and long-term memory tests. The anti-amnesic effects of pregnenolone sulphate remained unchanged. These observations bring a molecular basis to the modulatory role of σ1 receptors in memory, and reveal that the anti-amnesic action of neuroactive steroids may not similarly involve an interaction with σ1 receptors. British Journal of Pharmacology (2001) 134, 1731–1741; doi:10.1038/sj.bjp.0704355
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sa4503 a novel cognitive enhancer with σ1 receptor agonist properties facilitates nmda receptor dependent learning in mice
European Journal of Pharmacology, 1997Co-Authors: Tangui Maurice, Alain PrivatAbstract:Abstract The selective σ1 receptor agonist 1-(3,4-dimethoxyphenethyl)-4-(3-phenyl propyl)piperazine dihydrochloride (SA4503) was reported to reverse the Amnesia induced by the muscarinic receptor antagonist scopolamine at sub-mg/kg doses. We examined its effect on the learning impairment induced in mice by the non-competitive NMDA receptor antagonist dizocilpine. Learning capacities were evaluated using spontaneous alternation in the Y-maze for spatial working memory, and step-down type passive avoidance. SA4503 (0.03–1 mg/kg s.c.) attenuated the dizocilpine (0.15 mg/kg i.p.)-induced memory deficits following a bell-shaped curve in both tests. These effects of SA4503 were blocked by haloperidol (0.05 mg/kg i.p.), implicating σ1 receptors. SA4503 also reversed the alternation deficit induced by Nω-nitro- l -arginine methyl ester ( l -NAME, 100 mg/kg i.p.) at the same dosage, indicating that it acted on working memory through the nitric oxide (NO)-mediated signalling pathway. Furthermore, progesterone (2 mg/kg s.c.) blocked the SA4503 effects in the dizocilpine- and l -NAME-Amnesia models, in accordance with the purported neurosteroids/σ1 receptors interaction. These results demonstrate a promising neurobehavioural profile of SA4503, a ligand equally efficient to reverse the deficit in the glutamatergic as well as in the cholinergic Amnesia model. Pertinent informations on the potential mechanism of the anti-amnesic effects of σ1 receptor ligands were also obtained.
Minsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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terminalia chebula extract prevents scopolamine induced Amnesia via cholinergic modulation and anti oxidative effects in mice
BMC Complementary and Alternative Medicine, 2018Co-Authors: Minsoo Kim, Dong Young Lee, Jun Lee, Hyun Woo Kim, Sang Hyun Sung, Jungsoo Han, Won Kyung JeonAbstract:Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates Amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects. TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined. In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA. These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for Amnesia.
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Terminalia chebula extract prevents scopolamine-induced Amnesia via cholinergic modulation and anti-oxidative effects in mice
BMC, 2018Co-Authors: Minsoo Kim, Dong Young Lee, Jun Lee, Hyun Woo Kim, Sang Hyun Sung, Jungsoo Han, Won Kyung JeonAbstract:Abstract Background Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates Amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects. Methods TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1–14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8–14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined. Results In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA. Conclusion These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for Amnesia