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Memory Consolidation (memory + consolidation)
Selected AbstractsThe role of medial temporal lobe in retrieving spatial and nonspatial relations from episodic and semantic memoryHIPPOCAMPUS, Issue 1 2010Lee Ryan Abstract This study examined the involvement of medial temporal lobe, especially the hippocampus, in processing spatial and nonspatial relations using episodic and semantic versions of a relational judgment task. Participants studied object arrays and were tested on different types of relations between pairs of objects. Three prevalent views of hippocampal function were considered. Cognitive map theory (O'Keefe and Nadel (1978) The Hippocampus as a Cognitive Map. USA: Oxford University Press) emphasizes hippocampal involvement in spatial relational tasks. Multiple trace theory (Nadel and Moscovitch (1997) Memory consolidation, retrograde amnesia and the hippocampal complex Curr Opin Neurobiol 7:217,227) emphasizes hippocampal involvement in episodic tasks. Eichenbaum and Cohen's ((2001) From Conditioning to Conscious Recollection: Memory Systems of the Brain. USA: Oxford University Press) relational theory predicts equivalent hippocampal involvement in all relational tasks within both semantic and episodic memory. The fMRI results provided partial support for all three theories, though none of them fit the data perfectly. We observed hippocampal activation during all relational tasks, with increased activation for spatial compared to nonspatial relations, and for episodic compared to semantic relations. The placement of activation along the anterior-posterior axis of the hippocampus also differentiated the conditions. We suggest a view of hippocampal function in memory that incorporates aspects of all three theories. © 2009 Wiley-Liss, Inc. [source] The effect of a REM sleep deprivation procedure on different aspects of memory function in humansPSYCHOPHYSIOLOGY, Issue 2 2008Ingvild West Saxvig Abstract Previous studies have suggested that memory is dependent on the occurrence of REM sleep. Research has mainly focused on two distinct types of memory function, declarative and procedural, and it seems that the latter may more directly depend on REM sleep. Memory consolidation has been more investigated than acquisition, maintenance, and recall, despite the fact that sleep may affect flow of information into/from storage. Moreover, tests have often been limited to stimuli within only one modality (usually visual or verbal). This study aimed to clarify the role of REM sleep in memory by investigating aspects of memory function, processing, and modality in the same experimental setting. Tests of acquisition and consolidation of multiple aspects of memory function within the visual and verbal modalities were administrated to subjects before and after REM sleep deprivation. Results show that test performance was not affected by REM sleep deprivation. [source] Sleep-related memory consolidation in depression: an emerging field of researchDEPRESSION AND ANXIETY, Issue 12 2008Orla Patricia Hornung Ph.D. Abstract Sleep-related memory consolidation has received increasing attention in recent years. Because previous research has focused on healthy young adults, only very few studies have been conducted in patients with psychiatric disorders so far. The investigation of sleep-related memory consolidation in depression offers a wide range of future research opportunities and can therefore be regarded as an emerging field of research. This article gives a short overview of current knowledge of sleep-related memory consolidation in healthy young adults and builds a bridge to psychiatry and depression, where further research is urgently needed. Depression and Anxiety, 2008. © 2007 Wiley-Liss, Inc. [source] A role for eukaryotic translation initiation factor 2B (eIF2B) in taste memory consolidation and in thermal control establishment during the critical period for sensory developmentDEVELOPMENTAL NEUROBIOLOGY, Issue 6 2007Sharon Tirosh Abstract All species exhibit critical periods for sensory development, yet very little is known about the molecules involved in the changes in the network wiring that underlies this process. Here the role of transcription regulation of the translation machinery was determined by evaluating the expression of eIF2B,, an essential component of translation initiation, in both taste-preference development and thermal control establishment in chicks. Analysis of the expression pattern of this gene after passive-avoidance training revealed clear induction of eIF2B, in both the mesopallium intermediomediale (IMM) and in the striatum mediale (StM). In addition, a correlation was found between the concentration of methylanthranilate (MeA), which was the malaise substrate in the passive-avoidance training procedure, the duration of memory, and the expression level of eIF2B,. Training chicks on a low concentration of MeA induced short-term memory and low expression level of eIF2B,, whereas a high concentration of MeA induced long-term memory and a high expression level of eIF2B, in both the IMM and StM. Furthermore, eIF2B, -antisense "knock-down" not only reduced the amount of eIF2B, but also attenuated taste memory formation. In order to determine whether induction of eIF2B, is a general feature of neuronal plasticity, we checked whether it was induced in other forms of neuronal plasticity, with particular attention to its role in temperature control establishment, which represents hypothalamic-related plasticity. It was established that eIF2B, -mRNA was induced in the preopotic anterior hypothalamus during heat conditioning. Taken together, these results correlate eIF2B, with sensory development. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007. [source] One-Year Postoperative Autobiographical Memory Following Unilateral Temporal Lobectomy for Control of Intractable EpilepsyEPILEPSIA, Issue 3 2007Virginie Voltzenlogel Summary:,Purpose: To examine the effects of temporal lobectomy (TL), particularly concerning its lateralization. Methods: Patients completed autobiographical memory tests, preoperatively and 1-year postoperatively. Results: (a) right TL (RTL) patients recalled significantly more memories from the year after surgery than from the year before TL; (b) their pre to postoperative improvement on autobiographical memory scores was positively correlated to improvement of delayed story recall scores; and (c) 1 year after surgery, performance on recent personal memory recall was normalized for RTL patients only. Conclusion: We suggest that, in the absence of recurrent seizures, the relative integrity of the left hemisphere together with residual right hemisphere structures sustains postoperative autobiographical memory consolidation, at least 1 year postoperatively. [source] Conversation with Murray JarvikADDICTION, Issue 9 2001Article first published online: 1 SEP 200 In this occasional series we record the views and personal experience of people who have specially contributed to the evolution of ideas in the Journal's field of interest. Murray Jarvik's long and fruitful career in research and teaching spans the 50-year period beginning before the explosion of interest in psychopharmacology up to the present. His studies on LSD, among the first ever published, were followed by studies on the effects of drugs on memory and memory consolidation, which were then followed by studies on nicotine, smoking and pharmacological interventions in tobacco dependence. His contributions to the field of tobacco dependence have earned him international recognition. [source] Learning-associated regulation of polysialylated neural cell adhesion molecule expression in the rat prefrontal cortex is region-, cell type- and paradigm-specificEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008Judith P. F. Ter Horst Abstract The prefrontal cortex (PFC) is an interconnected set of cortical areas that function in the synthesis of a diverse range of information and production of complex behaviour. It is now clear that these frontal structures, through bidirectional excitatory communication with the hippocampal formation, also play a substantial role in long-term memory consolidation. In the hippocampus, morphological synaptic plasticity, supported by regulation of neural cell adhesion molecule (NCAM) polysialylation status, is crucial to information storage. The recent description of polysialylated neurons in the various fields of the medial PFC suggests these structures to possess a similar capacity for synaptic plasticity. Here, using double-labelling immunohistochemistry with glutamic acid decarboxylase 67, we report that the nature of NCAM polysialic acid-positive neurons in the PFC is region-specific, with a high proportion (30,50%) of a ,-aminobutyric acid (GABA)ergic phenotype in the more ventral infralimbic, orbitofrontal and insular cortices compared with just 10% in the dorsal structures of the cingulate, prelimbic and frontal cortices. Moreover, spatial learning was accompanied by activations in polysialylation expression in ventral PFC structures, while avoidance conditioning involved downregulation of this plasticity marker that was restricted to the dorsomedial PFC , the cingulate and prelimbic cortices. Thus, in contrast to other structures integrated functionally with the hippocampus, memory-associated plasticity mobilized in the PFC is region-, cell type- and task-specific. [source] Protein degradation, as with protein synthesis, is required during not only long-term spatial memory consolidation but also reconsolidationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2008Julien Artinian Abstract The formation of long-term memory requires protein synthesis, particularly during initial memory consolidation. This process also seems to be dependant upon protein degradation, particularly degradation by the ubiquitin-proteasome system. The aim of this study was to investigate the temporal requirement of protein synthesis and degradation during the initial consolidation of allocentric spatial learning. As memory returns to a labile state during reactivation, we also focus on the role of protein synthesis and degradation during memory reconsolidation of this spatial learning. Male CD1 mice were submitted to massed training in the spatial version of the Morris water maze. At various time intervals after initial acquisition or after a reactivation trial taking place 24 h after acquisition, mice received an injection of either the protein synthesis inhibitor anisomycin or the protein degradation inhibitor lactacystin. This injection was performed into the hippocampal CA3 region, which is specifically implicated in the processing of spatial information. Results show that, in the CA3 hippocampal region, consolidation of an allocentric spatial learning task requires two waves of protein synthesis taking place immediately and 4 h after acquisition, whereas reconsolidation requires only the first wave. However, for protein degradation, both consolidation and reconsolidation require only one wave, taking place immediately after acquisition or reactivation, respectively. These findings suggest that protein degradation is a key step for memory reconsolidation, as for consolidation. Moreover, as protein synthesis-dependent reconsolidation occurred faster than consolidation, reconsolidation did not consist of a simple repetition of the initial consolidation. [source] Dissociated theta phase synchronization in amygdalo- hippocampal circuits during various stages of fear memoryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2007Rajeevan T. Narayanan Abstract The amygdala and the hippocampus are critically involved in the formation and retention of fear memories. However, their precise contribution to, and their interplay during, fear memory formation are not fully understood. In the present study we investigated network activities in the amygdalo-hippocampal system of freely behaving mice at different stages of fear memory consolidation and retention. Our data show enhanced theta phase synchronization in this pathway during the retrieval of fear memory at long-term (24 h post-training), but not short-term (2 min, 30 min and 2 h post-training) stages, following both contextual and auditory cued conditioning. However, retrieval of remotely conditioned fear (30 days post-training) failed to induce an increase in synchronization despite there still being memory retention. Thus, our data indicate that the amygdalo-hippocampal interaction reflects a dynamic interaction of ensemble activities related to various stages of fear memory consolidation and/or retention, and support the notion that recent and remote memories are organized through different network principles. [source] Elements of a neurobiological theory of hippocampal function: the role of synaptic plasticity, synaptic tagging and schemasEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006R. G. M. MorrisArticle first published online: 8 JUN 200 Abstract The 2004 EJN Lecture was an attempt to lay out further aspects of a developing neurobiological theory of hippocampal function [Morris, R.G.M., Moser, E.I., Riedel, G., Martin, S.J., Sandin, J., Day, M. & O'Carroll, C. (2003) Phil. Trans. R. Soc. Lond. B Biol. Sci., 358, 773,786.] These are that (i) activity-dependent synaptic plasticity plays a key role in the automatic encoding and initial storage of attended experience; (ii) the persistence of hippocampal synaptic potentiation over time can be influenced by other independent neural events happening closely in time, an idea with behavioural implications for memory; and (iii) that systems-level consolidation of memory traces within neocortex is guided both by hippocampal traces that have been subject to cellular consolidation and by the presence of organized schema in neocortex into which relevant newly encoded information might be stored. Hippocampal memory is associative and, to study it more effectively than with previous paradigms, a new learning task is described which is unusual in requiring the incidental encoding of flavour,place paired associates, with the readout of successful storage being successful recall of a place given the flavour with which it was paired. NMDA receptor-dependent synaptic plasticity is shown to be critical for the encoding and intermediate storage of memory traces in this task, while AMPA receptor-mediated fast synaptic transmission is necessary for memory retrieval. Typically, these rapidly encoded traces decay quite rapidly over time. Synaptic potentiation also decays rapidly, but can be rendered more persistent by a process of cellular consolidation in which synaptic tagging and capture play a key part in determining whether or not it will be persistent. Synaptic tags set at the time of an event, even many trivial events, can capture the products of the synthesis of plasticity proteins set in train by events before, during or even after an event to be remembered. Tag,protein interactions stabilize synaptic potentiation and, by implication, memory. The behavioural implications of tagging are explored. Finally, using a different protocol for flavour,place paired associate learning, it is shown that rats can develop a spatial schema which represents the relative locations of several different flavours of food hidden at places within a familiar space. This schema is learned gradually but, once acquired, enables new paired associates to be encoded and stored in one trial. Their incorporation into the schema prevents rapid forgetting and suggests that schema play a key and hitherto unappreciated role in systems-level memory consolidation. The elements of what may eventually mature into a more formal neurobiological theory of hippocampal memory are laid out as specific propositions with detailed conceptual discussion and reference to recent data. [source] REM sleep enhancement induced by different procedures improves memory retention in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2003Wolfram Wetzel Abstract Growing evidence supports the idea that sleep following learning is critically involved in memory formation. Recent studies suggest that information acquired during waking is reactivated and possibly consolidated during subsequent sleep, especially during rapid-eye movement (REM) or paradoxical sleep (PS). Critical reviews, however, have questioned PS and memory relationships, particularly because of shortcomings of the PS deprivation paradigm applied in many studies. Therefore, in the present study we used an opposite strategy, i.e. we investigated the effects of PS enhancement on memory retention. In three experiments, we found that selective PS enhancement, induced by different procedures after discrimination training in rats, results in increased retention tested 24 h later. Moreover, calculated in all animals (n = 61), there was a highly significant correlation between post-training PS values and retention scores. Our results suggest that an experimentally induced increase of PS after learning facilitates memory consolidation. [source] Long-lasting hippocampal potentiation and contextual memory consolidationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2001Benedetto Sacchetti Abstract In order to ascertain whether there are hippocampal electrophysiological modifications specifically related to memory, exploratory activity and emotional stress, extracellular electrical activity was recorded in hippocampal slices prepared from the brains of male adult rats. Several groups of animals were employed: (i) rats which had freely explored the experimental apparatus (8 min exposure); (ii) rats which had been subjected, in the same apparatus, to a fear conditioning paradigm training entailing the administration of aversive electrical footshocks (8 min exposure); (iii) rats to which the same number of aversive shocks had been administered in the same apparatus, but temporally compressed so as to make difficult the association between painful stimuli and the apparatus (30 s exposure); (iv) naïve rats never placed in the apparatus. Half of the rats from each treatment group were used for retrieval testing and the other half for hippocampal excitability testing. The conditioned freezing response was exhibited for no less than 4 weeks. Hippocampal excitability was measured by means of input,output curves (IOC) and paired-pulse facilitation curves (PPF). Retrieval testing or brain slices preparation were performed at increasing delays after the training sessions: immediately afterwards or after 1, 7 or 28 days. Only the rats subjected to the fear conditioning training exhibited freezing when placed again in the apparatus (retrieval testing). It was found that IOCs, with respect to naïve rats, increased in the conditioned animals up to the 7-day delay. In free exploration animals the IOCs increased only immediately after the training session. In all other rats no modification of the curves was observed. IOC increases do not appear to imply presynaptic transmitter release modifications, because they were not accompanied by PPF modifications. In conclusion, a clear-cut correlation was found between the increase in excitability of the Schaffer collateral,CA1 dendrite synapses and freezing response consolidation. [source] Reactivation with a simple exposure to the experimental environment is sufficient to induce reconsolidation requiring protein synthesis in the hippocampal CA3 region in miceHIPPOCAMPUS, Issue 3 2007Julien Artinian Abstract Our understanding of the memory reconsolidation process is at an earlier stage than that of consolidation. For example, it is unclear if, as for memory consolidation, reconsolidation of a memory trace necessitates protein synthesis. In fact, conflicting results appear in the literature and this discrepancy may be due to differences in the experimental reactivation procedure. Here, we addressed the question of whether protein synthesis in the CA3 hippocampal region is crucial in memory consolidation and reconsolidation of allocentric knowledge after reactivation in different experimental conditions in the Morris water maze. We showed (1) that an injection of the protein synthesis inhibitor anisomycin in the CA3 region during consolidation or after a single reactivation trial disrupted performance and (2) that protein synthesis is required even after a simple contextual reactivation without any learning trial and independently of the presence of the reinforcement. This work demonstrates that a simple exposure to the spatial environment is sufficient to reactivate the memory trace, to make it labile, and that reconsolidation of this trace requires de novo protein synthesis. © 2007 Wiley-Liss, Inc. [source] Single neuron burst firing in the human hippocampus during sleepHIPPOCAMPUS, Issue 6 2002Richard J. Staba Abstract Although there are numerous non-primate studies of the single neuron correlates of sleep-related hippocampal EEG patterns, very limited hippocampal neuronal data are available for correlation with human sleep. We recorded human hippocampal single neuron activity in subjects implanted with depth electrodes required for medical diagnosis and quantitatively evaluated discharge activity from each neuron during episodes of wakefulness (Aw), combined stage 3 and 4 slow-wave sleep (SWS), and rapid eye movement (REM) sleep. The mean firing rate of the population of single neurons was significantly higher during SWS and Aw compared with REM sleep (p = 0.002; p < 0.0001). In addition, burst firing was significantly greater during SWS compared with Aw (p = 0.001) and REM sleep (p < 0.0001). The synchronized state of SWS and associated high-frequency burst discharge found in human hippocampus may subserve functions similar to those reported in non-primate hippocampus that require burst firing to induce synaptic modifications in hippocampal circuitry and in hippocampal projections to neocortical targets that participate in memory consolidation. Hippocampus 2002;12:724,734. © 2002 Wiley-Liss, Inc. [source] Verbal memory improved by D -amphetamine: influence of the testing effectHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 5 2010Inge Zeeuws Abstract Objective The improvement of long-term retention of verbal memory after an acute administration of D -amphetamine in recall and recognition tasks has been ascribed to an influence of the drug on memory consolidation. Because recent research has demonstrated that intermediate testing is of overriding importance for retention, we investigated whether D -amphetamine modulates the repeated testing effect in verbal long-term recognition. Method Forty men participated in two double blind placebo controlled studies. In Experiment 1, we manipulated the number of recognition tests and in Experiment 2, we compared repeated with nonrepeated testing of the same items. Results Drug effects were observed on delayed tests only, leaving immediate recognition unaffected. Number of intermediate recognition tests and repeated testing of the same items were not affected by D -amphetamine. Conclusions We conclude that the D -amphetamine memory enhancement is not related to the testing effect. This result supports that D -amphetamine modulates other aspects of the consolidation process, probably related to context effects. Copyright © 2010 John Wiley & Sons, Ltd. [source] MRI diffusion tensor tracking of a new amygdalo-fusiform and hippocampo-fusiform pathway system in humansJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2009Charles D. Smith MD Abstract Purpose To use MRI diffusion-tensor tracking (DTT) to test for the presence of unknown neuronal fiber pathways interconnecting the mid-fusiform cortex and anteromedial temporal lobe in humans. Such pathways are hypothesized to exist because these regions coactivate in functional MRI (fMRI) studies of emotion-valued faces and words, suggesting a functional link that could be mediated by neuronal connections. Materials and Methods A total of 15 normal human subjects were studied using unbiased DTT approaches designed for probing unknown pathways, including whole-brain seeding and large pathway-selection volumes. Several quality-control steps verified the results. Results Parallel amygdalo-fusiform and hippocampo-fusiform pathways were found in all subjects. The pathways begin/end at the mid-fusiform gyrus above the lateral occipitotemporal sulcus bilaterally. The superior pathway ends/begins at the superolateral amygdala. The inferior pathway crosses medially and ends/begins at the hippocampal head. The pathways are left-lateralized, with consistently larger cross-sectional area, higher anisotropy, and lower minimum eigenvalue (D-min) on the left, where D-min assesses intrinsic cross-fiber diffusivity independent of curvature. Conclusion A previously-undescribed pathway system interconnecting the mid-fusiform region with the amygdala/hippocampus has been revealed. This pathway system may be important for recognition, memory consolidation, and emotional modulation of face, object, and lexical information, which may be disrupted in conditions such as Alzheimer's disease. J. Magn. Reson. Imaging 2009. © 2009 Wiley-Liss, Inc. [source] Inhibition of A, aggregation and neurotoxicity by the 39-kDa receptor-associated proteinJOURNAL OF NEUROCHEMISTRY, Issue 5 2010Megan L. Kerr J. Neurochem. (2010) 112, 1199,1209. Abstract Aggregation of ,-amyloid protein (A,) to form oligomers is considered to be a key step in generating neurotoxicity in the Alzheimer's disease brain. Agents that bind to A, and inhibit oligomerization have been proposed as Alzheimer's disease therapeutics. In this study, we investigated the binding of fluorescein-labeled A,1,42 (FluoA,1,42) to SH-SY5Y neuroblastoma cells and examined the effect of the 39-kDa receptor-associated protein (RAP), on the A, cell interaction. FluoA,1,42 bound to the cells in a punctate pattern. Surprisingly, when RAP was added to the incubations, FluoA,1,42 and RAP were found to be co-localized on the cell surface, suggesting that RAP and A, may bind to each other. Experiments using the purified proteins confirmed that a RAP,A, complex was stable and resistant to sodium dodecyl sulfate. RAP also inhibited A, oligomerization. We next examined whether RAP could inhibit the neurotoxic effects of A,. Addition of A,1,42 to SH-SY5Y cells caused an increase in intracellular Ca2+ that was inhibited by treatment of the A, peptide with RAP. RAP also blocked an A,-induced inhibition of long-term memory consolidation in 1-day-old chicks. This study demonstrates that RAP binds to A, and is an inhibitor of the neurotoxic effects of A,. [source] Alcohol Exposure Alters the Expression Pattern of Neural Cell Adhesion Molecules During Brain DevelopmentJOURNAL OF NEUROCHEMISTRY, Issue 3 2000R. Miñana Abstract: Neural cell adhesion molecules (NCAMs) play critical roles during development of the nervous system. The aim of this study is to investigate the possible effect of ethanol exposure on the pattern of expression and sialylation of NCAM isoforms during postnatal rat brain development because alterations in NCAM content and distribution have been associated with defects in cell migration, synapse formation, and memory consolidation, and deficits in these processes have been observed after in utero alcohol exposure. The expression of NCAM isoforms in the developing cerebral cortex of pups from control and alcohol-fed mothers was assessed by western blotting, ribonuclease protection assay, and immunocytochemistry. The highly sialylated form of NCAM [polysialic acid (PSA)-NCAM] is mainly expressed during the neonatal period and then is down-regulated in parallel with the appearance of NCAM 180 and NCAM 140. Ethanol exposure increases PSA-NCAM levels during the neonatal period, delays the loss of PSA-NCAM, decreases the amount of NCAM 180 and NCAM 140 isoforms, and reduces sialyltransferase activity during postnatal brain development. Neuraminidase treatment of ethanol-exposed neonatal brains leads to more intense band degradation products, suggesting a higher content of NCAM polypeptides carrying PSA in these samples. However, NCAM mRNA levels are not changed by ethanol. Immunocytochemical analysis demonstrates that ethanol triggers an increase in PSA-NCAM immunolabeling in the cytoplasm of astroglial cells, accompanied by a decrease in immunogold particles over the plasma membrane. These findings indicate that ethanol exposure during brain development alters the pattern of NCAM expression and suggest that modification of NCAM could affect neuronal-glial interactions that might contribute to the brain defects observed after in utero alcohol exposure. [source] A Synthetic Peptide Ligand of Neural Cell Adhesion Molecule (NCAM) IgI Domain Prevents NCAM Internalization and Disrupts Passive Avoidance LearningJOURNAL OF NEUROCHEMISTRY, Issue 6 2000Andrew G. Foley Abstract: The neural cell adhesion molecule (NCAM) mediates cell adhesion and signal transduction through trans -homophilic- and/or cis -heterophilic-binding mechanisms. Intraventricular infusions of anti-NCAM have revealed a functional requirement of NCAM for the consolidation of memory in rats and chicks in a specific interval 6-8 h after training. We have now extended these studies to a synthetic peptide ligand of NCAM (C3) with an affinity for the IgI domain and the capability of inhibiting NCAM-mediated neurite outgrowth in vitro. Intraventricular administration of a single 5 ,g bolus of C3 strongly inhibited recall of a passive avoidance response in adult rats, when given during training or in the 6-8-h posttraining period. The effect of C3 on memory consolidation was similar to that obtained with anti-NCAM as the amnesia was not observed until the 48-h recall time. The unique amnesic action of C3 during training could be related to disrupted NCAM internalization following training. In the 3-4-h posttraining period NCAM 180, the synapse-associated isoform, was down-regulated in the hippocampal dentate gyrus. This effect was mediated by ubiquitination and was prevented by C3 administration during training. These findings indicate NCAM to be involved in both the acquisition and consolidation of a passive avoidance response in the rat. Moreover, the study provides the first in vivo evidence for NCAM internalization in learning and identifies a synthetic NCAM ligand capable of modulating memory processes in vivo. [source] Fast Effects of Glucocorticoids on Memory-Related Network Oscillations in the Mouse HippocampusJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2008E. K. Weiss Transient or lasting increases in glucocorticoids accompany deficits in hippocampus-dependent memory formation. Recent data indicate that the formation and consolidation of declarative and spatial memory are mechanistically related to different patterns of hippocampal network oscillations. These include gamma oscillations during memory acquisition and the faster ripple oscillations (approximately 200 Hz) during subsequent memory consolidation. We therefore analysed the effects of acutely applied glucocorticoids on network activity in mouse hippocampal slices. Evoked field population spikes and paired-pulse responses were largely unaltered by corticosterone or cortisol, respectively, despite a slight increase in maximal population spike amplitude by 10 ,m corticosterone. Several characteristics of sharp waves and superimposed ripple oscillations were affected by glucocorticoids, most prominently the frequency of spontaneously occurring sharp waves. At 0.1 ,m, corticosterone increased this frequency, whereas maximal (10 ,m) concentrations led to a reduction. In addition, gamma oscillations became slightly faster and less regular in the presence of high doses of corticosteroids. The present study describes acute effects of glucocorticoids on sharp wave-ripple complexes and gamma oscillations in mouse hippocampal slices, revealing a potential background for memory deficits in the presence of elevated levels of these hormones. [source] Cyclic guanosine monophosphate signalling pathway plays a role in neural cell adhesion molecule-mediated neurite outgrowth and survivalJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2007Dorte Kornerup Ditlevsen Abstract The neural cell adhesion molecule (NCAM) plays a crucial role in neuronal development, regeneration, and synaptic plasticity associated with learning and memory consolidation. Homophilic binding of NCAM leads to neurite extension and neuroprotection in various types of primary neurons through activation of a complex network of signalling cascades, including fibroblast growth factor receptor, Src-family kinases, the mitogen-activated protein kinase pathway, protein kinase C, phosphatidylinositol-3 kinase, and an increase in intracellular Ca2+. Here we present data indicating an involvement of cyclic GMP in NCAM-mediated neurite outgrowth in both hippocampal and dopaminergic neurons and in NCAM-mediated neuroprotection of dopaminergic neurons. In addition, evidence is presented suggesting that NCAM mediates activation of cGMP via synthesis of nitric oxide (NO) by NO synthase (NOS) and activation of soluble guanylyl cyclase by NO, leading to an increased synthesis of cGMP and activation by cGMP of protein kinase G. © 2007 Wiley-Liss, Inc. [source] Chronic and High Alcohol Consumption Has a Negative Impact on Sleep and Sleep-Associated Consolidation of Declarative MemoryALCOHOLISM, Issue 5 2009Klaus Junghanns Background., The importance of sleep for memory consolidation has become a major focus of research. While it is known that abstaining alcohol-dependent patients often have sleep disorders and that there is some cognitive impairment during early abstention a possible interaction of disturbed sleep with overnight memory consolidation has not been addressed in a study as yet. Methods., Twenty-four alcohol-dependent patients with a short abstention period (mean 21.9 ± 7.6 days) were compared with 12 patients with an abstention period of several months (115.7 ± 43.8 days). Groups did not differ with respect to daily alcohol consumption before treatment, duration of alcohol dependence, and age. Before sleep all patients learned a list of semantically associated word pairs and a face name association task to a fixed criterion (at least 60% of correct recall) and they performed a mirror tracing task. After a polysomnographically registered night the patients were tested for retention of the learned declarative material by cued recall and had to perform the mirror tracing task again. Results., The groups did not differ with respect to sleep parameters or sleep-associated memory consolidation. Across both groups the duration of alcohol dependence correlated negatively with the amount of non-REM sleep and recall in the face name association task correlated negatively with daily alcohol consumption before abstention. Among the longer-term abstainers the duration of abstention correlated with the amount of slow wave sleep. Conclusions., Our data support the hypothesis that chronic and high alcohol consumption negatively affects sleep and declarative memory consolidation during the first months of abstention. Between an abstention period of a few weeks and of several months no change in sleep parameters and nightly memory consolidation could be demonstrated, however. [source] No persisting effect of partial sleep curtailment on cognitive performance and declarative memory recall in adolescentsJOURNAL OF SLEEP RESEARCH, Issue 1-Part-I 2010MARTA KOPASZ Summary Growing evidence indicates that sleep facilitates learning and memory processing. Sleep curtailment is increasingly common in adolescents. The aim of this study was to examine the effects of short-term sleep curtailment on declarative memory consolidation in adolescents. A randomized, cross-over study design was chosen. Twenty-two healthy subjects, aged 14,16 years, spent three consecutive nights in the sleep laboratory with a bedtime of 9 h during the first night (adaptation), 4 h during the second (partial sleep curtailment) and 9 h during the third night (recovery). The control condition consisted of three consecutive nights with bedtimes of 9 h. Both experimental conditions were separated by at least 3 weeks. The acquisition phase for the declarative tests was between 16:00 and 18:00 hours before the second night. Memory performance was examined in the morning after the recovery night. Executive function, attention and concentration were also assessed to control for any possible effects of tiredness. During the 4-h night, we observed a curtailment of 50% of non-rapid eye movement (non-REM), 5% of slow wave sleep (SWS) and 70% of REM sleep compared with the control night. Partial sleep curtailment of one night did not influence declarative memory retrieval significantly. Recall in the paired-associate word list task was correlated positively with percentage of non-REM sleep in the recovery night. Declarative memory consolidation does not appear to be influenced by short-term sleep curtailment in adolescents. This may be explained by the high ability of adolescents to compensate for acute sleep loss. The correlation between non-REM sleep and declarative memory performance supports earlier findings. [source] Learning-dependent changes in sleep spindles and Stage 2 sleepJOURNAL OF SLEEP RESEARCH, Issue 3 2006STUART M. FOGEL Summary It has become increasingly clear that sleep is necessary for efficient memory consolidation. Recently, it has been found that Stage 2 sleep disruption impairs procedural memory performance, and that memory performance is correlated with the duration of Stage 2 sleep; but the mechanisms involved in synaptic plasticity for procedural memory during sleep have not been identified. The present study examined the learning-dependent changes in sleep, including Stage 2 sleep spindles. Following an intense period of simple motor procedural learning, the duration of Stage 2 sleep and spindle density increased. There were no changes observed in the duration of any other stage of sleep or in the density of rapid eye movements. These findings support the hypothesis that sleep spindles are involved in the off-line reprocessing of simple motor procedural memory during Stage 2 sleep. [source] Intramodal and crossmodal processing delays in the attentional blink paradigm revealed by event-related potentialsPSYCHOPHYSIOLOGY, Issue 5 2008Alexia Ptito Abstract In the attentional blink (AB), processing of a second target (T2) is impaired if it is presented shortly after the onset of a first target (T1), leading to a decrease in accurate report of T2 if T2 is masked. Some prominent theories of the AB suggest that an amodal bottleneck in working memory consolidation underlies the AB. We investigated this by factorially manipulating T1 and T2 modalities (visual or auditory) using equivalent stimuli and tasks in both modalities to minimize task switching. T2 was not masked. In all modality combinations, the electrophysiological P3 component to T2, obtained by subtracting T1 only trials from T1+T2 trials, was delayed and reduced in amplitude when T2 was presented soon after T1 relative to when T1 and T2 were presented farther apart. Results provide support for a common amodal bottleneck that underlies the AB effects observed in all visual/auditory modality combinations. [source] The effects of ageing and cognitive impairment on on-line and off-line motor learningAPPLIED COGNITIVE PSYCHOLOGY, Issue 2 2010Jin H. Yan Skilled performance is a collective function of practice-related experiences (online learning) and post-practice memory consolidation during sleep (offline learning). This study examines the effects of ageing and cognitive impairment on the on- and offline learning of a point-to-point arm movement. In a 3-day experiment, older adults (cognitively normal or impaired) and young adults (YAs) were randomly assigned to practice or no-practice conditions. Changes in the dependent measures of movement time and timing error were analysed within and between conditions across days. The findings suggest that both age and cognitive function affect skill learning. YAs improved performance via both on- and offline learning whereas older adults with normal cognitive capacities appeared to learn the movement skill primarily in an online mode. Cognitive impairments were found to hinder both types of skill learning. Implications for motor skill acquisition and rehabilitation are briefly discussed. Copyright © 2009 John Wiley & Sons, Ltd. [source] The Myth of the Superiority of Concurrent Combined Treatments for Anxiety DisordersCLINICAL PSYCHOLOGY: SCIENCE AND PRACTICE, Issue 2 2010Kristin E. Pontoski [Clin Psychol Sci Prac 17: 107,111, 2010] The treatment of anxiety disorders with combined cognitive-behavioral therapy (CBT) and pharmacological treatments has been an ongoing topic of discussion. Combined treatments have failed to demonstrate additive benefits despite their continued use in practice. Otto, McHugh, and Kantak (2010) suggest that concurrent use of medication and CBT affects the acute release of cortisol during the extinction phase of exposure therapy and, in turn, interferes with memory consolidation. This commentary expands on some of the psychological aspects of combined treatments for anxiety disorders to consider along with this new biochemical perspective. [source] | ||||||||||||||||