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Memory Function (memory + function)
Selected AbstractsMemory function in normal agingACTA NEUROLOGICA SCANDINAVICA, Issue 2003Lars-Göran Nilsson Basic findings obtained on memory functions in normal aging are presented and discussed with respect to five separate but interacting memory systems. These systems are: episodic memory, semantic memory, short-term memory, perceptual representation system and procedural memory. All available evidence from cross-sectional research shows that there is a linear, decreasing memory performance as a function of age for episodic memory. Longitudinal studies suggest, however, that this age deficit may be an overestimation, by showing a relatively stable performance level up to middle age, followed by a sharp decline. Studies on semantic memory, short-term memory, perceptual representation system, and procedural memory show a relatively constant performance level across the adult life span, although some tasks used to assess short-term memory and procedural memory have revealed an age deficit. Disregarding the mixed results for these latter two memory systems, it can be concluded that episodic memory is unique in showing an age deficit. Episodic memory is also unique in the sense that it is the only memory system showing gender differences in performance throughout the adult life span with a significantly higher performance for women. [source] Effects of desmopressin (DDAVP) on memory impairment following electroconvulsive therapy (ECT)ACTA NEUROPSYCHIATRICA, Issue 3 2004Ebrahim Abdollahian Background:, Memory impairment is a common adverse effect of electroconvulsive therapy (ECT). Studies on animals and humans suggest that vasopressin improves the cognitive function, and positive effects of desmopressin on memory and learning have been reported. This research was performed for evaluation of the effects of desmopressin in the prevention of memory impairment following ECT. Methods:, This randomized, double-blind controlled clinical trial with placebo administration was performed on 50 patients with psychiatric disorders who were candidates for ECT. Subjects in the case group received 60 µm of intranasal desmopressin daily (in three doses of 20 µm). For the control group 0.9% saline solution was administered in the same way. Memory function was evaluated using Wechsler's Memory Scale three times a week (the first time before the start of ECT and the second and third times after the third and sixth sessions, respectively). Results were analyzed by t -test and Paired t -test. Results:, The mean age of patients was 29 years (range 20,40). During the course of ECT, patients in the control group demonstrated a meaningful decrease in memory scores (from a base score of 80.15,75.45 in the second test and 72.60 in the third test). Despite this, a meaningful increase in memory scores was observed during the treatment with desmopressin in the case group (from a base score of 73.27,75.70 and 79.13 in the second and the third tests, respectively). There was a meaningful difference between the two groups (P < 0.0001). Conclusion:, This study confirms the protective effect of desmopressin against memory impairment. The results confirm that memory impairment is a common side-effect of ECT and suggest that desmopressin may prevent ECT-induced memory impairment by its effects on memory and the learning process. [source] The Localization and Lateralization of Memory Deficits in Children with Temporal Lobe EpilepsyEPILEPSIA, Issue 1 2007Linda M. Gonzalez Summary:,Purpose: It is often reported that children with temporal lobe epilepsy (TLE) experience nonlateralized memory impairments. However, many of these studies have been exploratory and not based on memory theory. Further, differences between mesial and lateral subgroups have not been adequately examined. This study aimed to discern more specific patterns of memory impairment in children with TLE. Methods: Forty-three children (5,16 years) with lesional TLE participated. Subjects were categorized in terms of lesion laterality (left, n = 21; right, n = 22) and intratemporal location (mesial, n = 31; lateral, n = 12). Verbal and nonverbal memory tasks were administered that reflected associative, allocentric and recognition paradigms. Results: Facial recognition was poorer in right TLE (p = 0.03). There were no differences between left and right groups on any other memory task, even when comparisons were restricted to cases with mesial involvement. Irrespective of laterality, clear differences were observed between mesial and lateral lesion subgroups (arbitrary associative learning, p = 0.01; complex figure recall, p = 0.03). The lateral lesion subgroup displayed intact memory function relative to normative standards. Conclusions: Memory is more frequently impaired in children with mesial as opposed to lateral TLE. Tasks with an associative component discriminated between these subgroups, supporting an associative model of hippocampal function. With the exception of facial recognition, memory deficits were not lateralized. Therefore, the nature of memory impairment experienced by children with TLE cannot be extrapolated from adult models. [source] Functional MRI Predicts Memory Performance after Right Mesiotemporal Epilepsy SurgeryEPILEPSIA, Issue 2 2005Jozsef Janszky Summary:,Purpose: Anterior temporal lobe resection (ATR) is a treatment option in drug-resistant epilepsy. An important risk of ATR is loss of memory because mesiotemporal structures contribute substantially to memory function. We investigated whether memory-activated functional MRI (fMRI) can predict postoperative memory loss after anterior temporal lobectomy in right-sided medial temporal lobe epilepsy (MTLE). Methods: We included 16 patients (10 women) aged 16,54 years. The mean age at epilepsy onset was 12.5 years (range, 1,26 years). The patients' mean Wechsler IQ score was 95.2 (range, 62,125). The activation condition of fMRI consisted of retrieval from long-term memory induced by self-paced performance of an imaginative walk. All but one patient had left-sided speech dominance according to speech-activated fMRI. Outside the scanner, we evaluated the pre- and postoperative visual memory retention by using Rey Visual Design Learning Test. Results: We found a correlation between the preoperative asymmetry index of memory- fMRI and the change between pre- and postsurgical measures of memory retention. Reduced activation of the mesiotemporal region ipsilateral to the epileptogenic region correlated with a favorable memory outcome after right-sided ATR. Conclusions: In light of the postoperative results, the theoretical implication of our study is that fMRI based on a simple introspective retrieval task measures memory functions. The main clinical implication of our study is that memory- fMRI might replace the invasive Wada test in MTLE by using a simple fMRI paradigm. Predictive power, however, will be studied in larger patient samples. Other studies are required for left-sided MTLE and neocortical epilepsies to assess the clinical usefulness of memory- fMRI. [source] Morphological alterations in the amygdala and hippocampus of mice during ageingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2002Oliver Von Bohlen und Halbach Abstract Declines in memory function and behavioural dysfunction accompany normal ageing in mammals. However, the cellular and morphological basis of this decline remains largely unknown. It was assumed for a long time that cell losses in the hippocampus accompany ageing. However, recent stereological studies have questioned this finding. In addition, the effect of ageing is largely unknown in another key structure of the memory system, the amygdala. In the present study, we have estimated neuronal density and total neuronal numbers as well as density of fragments of degenerated axons in different hippocampal subfields and amygdaloid nuclei. Comparisons were made among aged (21,26 months old) mice and normal adult littermates (8 months old). No significant volume loss occurs in the hippocampus of aged mice. Small but insignificant reductions in total neuronal numbers were found in the hippocampus and in the amygdaloid nuclei. In contrast to the mild effects of ageing upon neuronal numbers, fragments of degenerated axons were increased in both hippocampus and amygdala of aged mice. These data suggest that ageing does not induce prominent cell loss in the hippocampus or amygdala, but leads to degeneration of axons that innervate these forebrain structures. Thus, mechanisms underlying age-related dysfunction depend on parameters other than neuronal numbers, at least in the hippocampal formation and the amygdala. [source] Predicting the Tails of Breakthrough Curves in Regional-Scale Alluvial SystemsGROUND WATER, Issue 4 2007Yong Zhang The late tail of the breakthrough curve (BTC) of a conservative tracer in a regional-scale alluvial system is explored using Monte Carlo simulations. The ensemble numerical BTC, for an instantaneous point source injected into the mobile domain, has a heavy late tail transforming from power law to exponential due to a maximum thickness of clayey material. Haggerty et al.'s (2000) multiple-rate mass transfer (MRMT) method is used to predict the numerical late-time BTCs for solutes in the mobile phase. We use a simple analysis of the thicknesses of fine-grained units noted in boring logs to construct the memory function that describes the slow decline of concentrations at very late time. The good fit between the predictions and the numerical results indicates that the late-time BTC can be approximated by a summation of a small number of exponential functions, and its shape depends primarily on the thicknesses and the associated volume fractions of immobile water in "blocks" of fine-grained material. The prediction of the late-time BTC using the MRMT method relies on an estimate of the average advective residence time, tad. The predictions are not sensitive to estimation errors in tad, which can be approximated by , where is the arithmetic mean ground water velocity and L is the transport distance. This is the first example of deriving an analytical MRMT model from measured hydrofacies properties to predict the late-time BTC. The parsimonious model directly and quantitatively relates the observable subsurface heterogeneity to nonlocal transport parameters. [source] Neuropsychological correlates of hippocampal and rhinal cortex volumes in patients with mesial temporal sclerosisHIPPOCAMPUS, Issue 8 2003Catherine E. O'Brien Abstract Considerable progress has been made toward understanding the function of the primate rhinal cortex, comprising the entorhinal (ErC) and perirhinal (PrC) cortices. However, translating animal models to human memory has been limited by the technological problems associated with characterizing neural structures in vivo. Functional correlates of hippocampal and rhinal cortex volume changes were examined in a sample of 61 temporal lobe epilepsy patients with mesial temporal sclerosis (MTS; 33 left, 28 right). Patients were administered the Wechsler Adult Intelligence Scale (revised or third edition), the Wechsler Memory Scale (revised or third edition), and a spatial maze task. Neuropsychological data, together with rhinal cortex and hippocampal volumes, collected in our earlier study (O'Brien CE, Bowden SC, Whelan G, Cook MJ, unpublished observations), were analyzed using multiple regression. The only significant predictor of verbal memory function was the difference score between the volume of left hippocampus and the left PrC. Spatial maze scores were predicted by the bilateral sum of ErC volume. The difference score between the left hippocampus and left PrC volumes was the most powerful predictor of verbal episodic memory. Right hippocampal volume was not a significant predictor of nonverbal episodic memory. Verbal and nonverbal semantic memory were not significantly predicted by any combination of rhinal cortex structures. This quantitative study suggests a lateralized or material-specific memory function for the left hippocampus and left PrC, in contrast to the bilateral role of the ErC. The left hippocampus and left PrC appear to act on verbal memory function through an opposing relationship. Finally, differentiation between hippocampal and subhippocampal components in terms of episodic and semantic memory, respectively, could not be supported by the current data. © 2003 Wiley-Liss, Inc. [source] The DSM-IV ,minor depression' disorder in the oldest-old: prevalence rate, sleep patterns, memory function and quality of life in elderly people of Italian descent in Southern BrazilINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 2 2002Flávio M. F. Xavier Abstract Objectives (1) To describe the prevalence of minor depression in a community-dwelling population aged 80 years and over. (2) To compare the sleep pattern, memory function and the prevalence rate of other psychiatric diagnoses between normal controls and subjects with minor depressive disorder. Design A random representative sample (sample,=,77 subjects/county population of oldest-old,=,219,35%) aged 80 years or more was selected from the county of Veranópolis in the Brazilian rural southern region. Of this group, eight subjects who met the DSM-IV criteria for minor depression, and 50 subjects without diagnosed delirium disorder, cognitive or affective problems were compared. Results The prevalence rate of minor depression was 12%. Subjects with this diagnosis were more likely to complain about sleep and memory problems than elderly people without any other affective disorder (major depression or dysthymic disorder). Otherwise, objective evaluation of these two areas, memory and sleep, did not show differences between the groups. Moreover, in terms of factors such as life satisfaction and some domains from the Short-form 36 Quality of Life Scale (SF-36), subjects with minor depression presented worse self-reported evaluations. Female gender was associated (p,=,0.01) with a more frequent presence of minor depression disorder, and those with this diagnosis were more likely to have co-morbidity with generalized anxiety disorder (p,=,0.007) when compared with elderly people without any depressive disorder. Conclusion In this study, minor depression has been significantly associated with lower life satisfaction and worse indexes of life quality. The results supported the current concept that minor depression is prevalent in later life, especially among the oldest-old. Subjects with minor depression had worse self-reported opinions about memory and sleep patterns, but when these variables were objectively measured, no meaningful differences could be determined by the research team. Female gender and the concurring presence of generalized anxiety disorder were both significantly associated with the presence of minor depression diagnosis. Copyright © 2002 John Wiley & Sons, Ltd. [source] Gene response elements, genetic polymorphisms and epigenetics influence the human dietary requirement for cholineIUBMB LIFE, Issue 6 2007Steven H. Zeisel Abstract Recent progress in the understanding of the human dietary requirement for choline highlights the importance of genetic variation and epigenetics in human nutrient requirements. Choline is a major dietary source of methyl-groups (one of choline's metabolites, betaine, participates in the methylation of homocysteine to form methionine); also choline is needed for the biosynthesis of cell membranes, bioactive phospholipids and the neurotransmitter acetylcholine. A recommended dietary intake for choline in humans was set in 1998, and a portion of the choline requirement can be met via endogenous de novo synthesis of phosphatidylcholine catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT) in the liver. Though many foods contain choline, many humans do not get enough in their diets. When deprived of dietary choline, most adult men and postmenopausal women developed signs of organ dysfunction (fatty liver, liver or muscle cell damage, and reduces the capacity to handle a methionine load, resulting in elevated homocysteine). However, only a portion of premenopausal women developed such problems. The difference in requirement occurs because estrogen induces expression of the PEMT gene and allows premenopausal women to make more of their needed choline endogenously. In addition, there is significant variation in the dietary requirement for choline that can be explained by common polymorphisms in genes of choline and folate metabolism. Choline is critical during fetal development, when it alters DNA methylation and thereby influences neural precursor cell proliferation and apoptosis. This results in long term alterations in brain structure and function, specifically memory function. IUBMB Life, 59: 380 - 387, 2007 [source] Serum Calcium and Cognitive Function in Old AgeJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2007Miranda T. Schram PhD OBJECTIVES: To determine whether serum calcium is associated with cognitive function in elderly individuals in the general population. DESIGN: Prospective follow-up study of two independent, population-based cohorts. SETTING: The Rotterdam Study (median follow-up 11 years) and the Leiden 85-plus Study (median follow-up 5 years). PARTICIPANTS: Three thousand nine hundred ninety-four individuals, mean age 71, from the Rotterdam Study and 560 individuals, all aged 85, from the Leiden 85-plus Study. MEASUREMENTS: Global cognitive function was assessed in both cohorts using the Mini-Mental State Examination; attention, psychomotor speed, and memory function were assessed in the Leiden 85-plus Study only. Linear regression and linear mixed models were used for statistical analyses. RESULTS: In the Rotterdam Study, high serum calcium was associated with worse global cognitive function at baseline (P<.05) and a faster rate of decline in cognitive function during follow-up (P=.005) in individuals aged 75 and older but not in younger individuals. In the Leiden 85-plus Study, high serum calcium was associated with worse global cognitive function from age 85 through 90 (P<.001). This observation also held for the specific cognitive domains tested (all P<.01). These results did not change when individuals with serum calcium levels greater than normal (>2.55 mmol/L) were excluded from the analyses. CONCLUSION: In the general population, high serum calcium levels are associated with faster decline in cognitive function over the age of 75. [source] Neuropsychological components of intellectual disability: the contributions of immediate, working, and associative memoryJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 5 2010Jamie O. Edgin Abstract Background Efficient memory functions are important to the development of cognitive and functional skills, allowing individuals to manipulate and store information. Theories of memory have suggested the presence of domain-specific (i.e. verbal and spatial) and general processing mechanisms across memory domains, including memory functions dependent on the prefrontal cortex (PFC) and the hippocampus. Comparison of individuals who have syndromes associated with striking contrasts in skills on verbal and spatial tasks [e.g. Down syndrome (DS) and Williams syndrome (WS)] allows us to test whether or not these dissociations may extend across cognitive domains, including PFC and hippocampal memory processes. Methods The profile of memory function, including immediate memory (IM), working memory (WM) and associative memory (AM), was examined in a sample of adolescents and young adults with DS (n = 27) or WS (n = 28), from which closely CA- and IQ-matched samples of individuals with DS (n = 18) or WS (n = 18) were generated. Relations between memory functions and IQ and adaptive behaviour were also assessed in the larger sample. Results Comparisons of the two matched groups indicated significant differences in verbal IM (DS < WS), spatial IM (DS > WS) and spatial and verbal AM (DS > WS), but no between-syndrome differences in WM. For individuals with DS, verbal IM was the most related to variation in IQ, and spatial AM related to adaptive behaviour. The pattern was clearly different for individuals with WS. Verbal and spatial AM were the most related to variation in IQ, and verbal WM related to adaptive behaviour. Conclusions These results suggest that individuals with these two syndromes have very different patterns of relative strengths and weaknesses on memory measures, which do not fully mirror verbal and spatial dissociations. Furthermore, different patterns of memory dysfunction relate to outcome in individuals with each syndrome. [source] Regulation of mitogen-activated protein kinases by glutamate receptorsJOURNAL OF NEUROCHEMISTRY, Issue 1 2007John Q. Wang Abstract Glutamate receptors regulate gene expression in neurons by activating intracellular signaling cascades that phosphorylate transcription factors within the nucleus. The mitogen-activated protein kinase (MAPK) cascade is one of the best characterized cascades in this regulatory process. The Ca2+ -permeable ionotropic glutamate receptor, mainly the NMDA receptor subtype, activates MAPKs through a biochemical route involving the Ca2+ -sensitive Ras-guanine nucleotide releasing factor, Ca2+/calmodulin-dependent protein kinase II, and phosphoinositide 3-kinase. The metabotropic glutamate receptor (mGluR), however, activates MAPKs primarily through a Ca2+ -insensitve pathway involving the transactivation of receptor tyrosine kinases. The adaptor protein Homer also plays a role in this process. As an information superhighway between surface glutamate receptors and transcription factors in the nucleus, active MAPKs phosphorylate specific transcription factors (Elk-1 and CREB), and thereby regulate distinct programs of gene expression. The regulated gene expression contributes to the development of multiple forms of synaptic plasticity related to long-lasting changes in memory function and addictive properties of drugs of abuse. This review, by focusing on new data from recent years, discusses the signaling mechanisms by which different types of glutamate receptors activate MAPKs, features of each MAPK cascade in regulating gene expression, and the importance of glutamate/MAPK-dependent synaptic plasticity in memory and addiction. [source] Effect of Environmental Enrichment on Stress Related Systems in RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 5 2004F. Moncek Abstract The aim of this study was to test whether environmental enrichment alters the status and responsiveness of pituitary-adrenocortical and sympathetic-adrenomedullary hormones in rats. Previous studies have shown that rats kept in an enriched environment differ from those kept in standard cages in dendritic branching, synaptogenesis, memory function, emotionality and behaviour. In male Wistar rats kept in an enriched environment for 40 days, we studied basal concentrations of hormones, endocrine responses to 5-HT1A challenge and responsiveness and adaptation to repeated handling. Environmental enrichment consisted of large plexiglass cages with 10 rats per cage, which contained variety of objects exchanged three times a week. Rats kept in this enriched environment had higher resting plasma concentrations of corticosterone, larger adrenals and increased corticosterone release to buspirone challenge compared to controls. Lower adrenocorticotropic hormone, corticosterone and adrenaline responses to handling were noticed in rats kept in an enriched environment. Exposure to repeated handling led to a more rapid extinction of corticosterone responses in rats kept in an enriched environment. Thus, environmental enrichment leads to pronounced changes in neuroendocrine regulation, including larger adrenals and increased adrenocortical function, which are so far considered to be indication of chronic stress. [source] New component of the limbic system: Marginal division of the neostriatum that links the limbic system to the basal nucleus of MeynertJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2003Si Yun Shu Abstract The limbic system refers to a group of connected neural regions that are associated with motivation, learning, and memory. The marginal division (MrD) is a zone located at the caudal border of the neostriatum in mammalian brains that has been shown to be involved in learning and memory. In a previous study, c-fos expression showed functional connections between the MrD, basal nucleus of Meynert (NBM) and limbic system (Shu et al., 1988a, 1999). In the present study, to explore the relationship between these regions, the expression of limbic system-associated membrane protein (LAMP) was investigated using molecular and immunohistochemical methods. Synaptic and functional connections between the MrD and the NBM were studied also using tract tracing, electron microscopic and behavioral methods. LAMP is thought to be a marker of the limbic system and expression of LAMP protein and mRNA was observed in both the MrD and the limbic system. From such results, it is concluded that the MrD is a new component of the limbic system. Fibers from the MrD were observed projecting and synapsing on cholinergic neurons of the NBM. As reduction of learning and memory was induced by lesioning the projection from the MrD to the NBM, it would seem that the MrD modulates the learning and memory function of the NBM. In conclusion, the results of these studies suggest that the MrD is a new component of the limbic system, and there are functional and structural connections between the MrD, NBM and limbic system. The MrD seems to act as a link between the limbic system and the NBM, and plays a role in learning and memory. © 2002 Wiley-Liss, Inc. [source] Verbal and Nonverbal Memory in Adults Prenatally Exposed to AlcoholALCOHOLISM, Issue 5 2010Claire D. Coles Background:, Neurocognitive effects of prenatal alcohol exposure in adulthood are not well documented. Questions persist regarding the extent to which there are specific, measurable effects beyond those associated with global ability deficits, whether individuals without the full fetal alcohol syndrome (FAS) demonstrate alcohol-related cognitive impairments, and whether observed memory effects are specific to a particular modality, i.e., verbal vs. visual/spatial domains. Methods:, In this study, verbal and nonverbal selective reminding paradigms were used to assess memory function in 234 young adults (M age: 22.78, SD: 1.79). Alcohol exposure was quantified prenatally. Alcohol groups included: Individuals with physical effects of alcohol exposure (Dysmorphic group, n = 47); Exposed individuals without such effects (n = 74). Contrast groups included: Controls (n = 59) matched for ethnicity, socioeconomic status, and hospital of birth; Special Education contrast group (n = 54) included to control for disability status. Memory outcomes entailed total recall, delayed recall, and measures of encoding and retrieval, and learning over trials as indexed by slope. Results:, Results indicated that Dysmorphic individuals were significantly less efficient in memory performance than Controls on all of the outcomes measured, but they did not differ from those in the Special Education contrast group. The nondysmorphic, alcohol-exposed group was intermediate in their performance, suggesting a continuum of effects of prenatal exposure. Evaluation of the encoding and retrieval aspects of memory performance indicated that learning rather than forgetting accounted for the deficits associated with prenatal alcohol exposure. Finally, no interaction was found between modality of presentation (verbal and nonverbal) and effects of alcohol exposure on memory performance. Conclusion:, These findings indicate that prenatal alcohol exposure is associated with persistent and specific effects on memory performance, and these problems result from less efficient encoding of information across both verbal and nonverbal modalities. Education and training efforts with this clinical group should take these characteristics into account. [source] Genuine Episodic Memory Deficits and Executive Dysfunctions in Alcoholic Subjects Early in AbstinenceALCOHOLISM, Issue 7 2007Anne Lise Pitel Background: Chronic alcoholism is known to impair episodic memory function, but the specific nature of this impairment is still unclear. Moreover, it has never been established whether episodic memory deficit in alcoholism is an intrinsic memory deficit or whether it has an executive origin. Thus, the objectives are to specify which episodic memory processes are impaired early in abstinence from alcohol and to determine whether they should be regarded as genuine memory deficits or rather as the indirect consequences of executive impairments. Methods: Forty recently detoxified alcoholic inpatients at alcohol entry treatment and 55 group-matched controls underwent a neuropsychological assessment of episodic memory and executive functions. The episodic memory evaluation consisted of 3 tasks complementing each other designed to measure the different episodic memory components (learning, storage, encoding and retrieval, contextual memory, and autonoetic consciousness) and 5 executive tasks testing capacities of organization, inhibition, flexibility, updating, and integration. Results: Compared with control subjects, alcoholic patients presented impaired learning abilities, encoding processes, retrieval processes, contextual memory and autonoetic consciousness. However, there was no difference between the 2 groups regarding the storage capacities assessed by the rate of forgetting. Concerning executive functions, alcoholic subjects displayed deficits in each executive task used. Nevertheless, stepwise regression analyses showed that only performances on fluency tasks were significantly predictive of some of the episodic memory disorders (learning abilities for 40%, encoding processes for 20%, temporal memory for 21%, and state of consciousness associated with memories for 26%) in the alcoholic group. Discussion: At alcohol treatment entry, alcoholic patients present genuine episodic memory deficits that cannot be regarded solely as the consequences of executive dysfunctions. These results are in accordance with neuroimaging findings showing hippocampal atrophy. Moreover, given the involvement of episodic memory and executive functions in alcohol treatment, these data could have clinical implications. [source] Impact and Prevention of Far-Field Sensing in Fallback Mode SwitchesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003PIERRE BORDACHER BORDACHAR, P., et al.: Impact and Prevention of Far-Field Sensing in Fallback Mode Switches.Far-field oversensing (FFOS) promoted by high atrial sensitivity and short atrial refractory periods induces false positive mode switches. We evaluated the incidence of ventricular FFOS in a population of DDD paced patients. Methods: One hundred thirty-seven patients (71 ± 10years, 76 men) implanted with a Talent DR pacemaker were studied. Before discharge, an analysis of internal data stored in the memories of the PM was performed by the specific software incorporated in the programmer in parallel with a 24-hour Holter recording. Data were validated by a panel of experts. One and 4 months follow-up was based only on the data stored in the PM memories. Results: Pacing indications were atrioventricular block(n = 75), sinus node dysfunction(n = 57), and other(n = 5). Sustained far-field oversensing was observed in 12/137 patients (9%). Out of a total of 3,511 triggered mode switch episodes, FFOS accounted for 20% and 7% of a 311 days cumulative time in mode switch. Inappropriate mode switch episodes induced by far-field were more numerous but shorter than episodes prompted by atrial arrhythmias. Atrial sensitivity was increased in eight patients, successfully in four. Reprogramming of the atrial refractory period(156 ± 11 ms)was successful in five of six patients. Conclusions: A 9% rate of ventricular FFOS was observed in an unselected population, easily and automatically diagnosed using the internal memory function and the automatic analysis provided by the programmer. Prolongation of the atrial refractory period was more effective than resetting of the atrial sensitivity in eliminating FFOS. (PACE 2003; 26[Pt. II]:206,209) [source] Neural correlates of memory in depression measured by brain perfusion SPECT at restPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 5 2009Hideki Azuma md Aim:, Brain metabolism activated studies have indicated associations between memory and the anterior cingulate cortex and hippocampus in patients with depression. The aim of the present study was therefore to investigate memory function, measured as performance on the Wechsler Memory Scale,Revised (WMS-R), and its relationship to brain perfusion using single-photon emission computed tomography (SPECT) at rest in patients with depression. Methods:, The Hamilton Rating Scale for Depression (HAMD) and WMS-R were measured for 17 patients with depression by an independent clinical evaluation team. Voxel-based correlation analyses were performed with statistical parametric mapping at an extent threshold of 200 voxels. Associations were controlled for state and trait factors. Results:, WMS-R measurements of verbal, visual, and general memory were inversely correlated with brain perfusion in the right anterior cingulate cortex, left premotor cortices, and both regions, respectively. The HAMD directly correlated with brain perfusion in the right anterior cingulate cortex. Conclusion:, Brain perfusion SPECT measurements of the anterior cingulate cortex at rest were associated with the severity of depression and immediate memory scores measured with the WMS-R. [source] Effect of cognitive training focusing on organizational strategies in patients with obsessive-compulsive disorderPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 6 2006HEE SOO PARK ma Abstract, The purpose of the present paper was to develop a cognitive training program for patients with obsessive-compulsive disorder (OCD) and evaluate its effectiveness. Nine 60-min sessions focusing on the improvement of organizational strategies were given to 15 patients with OCD over a period of 5 weeks. The control group consisted of 15 age- and sex-matched patients also with OCD. The Rey,Osterrieth Complex Figure Test and Korean,California Verbal Learning Test were administered before and after cognitive training. Clinical symptoms were assessed with the Yale,Brown Obsessive-Compulsive Scale. The memory function in the treatment group improved and their clinical symptoms were alleviated after training, compared to those of the control group. Cognitive training of OCD patients not only improved their memory function, but also alleviated their clinical symptoms. Therefore, cognitive training, focusing on the improvement of organizational strategies, could be an effective treatment modality for patients with OCD. [source] Neurobiological basis of behavioral and psychological symptoms in dementia of the Alzheimer typePSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 6 2000Kazuhiro Shinosaki MD Abstract Recent dementia studies indicate that behavioral and psychological symptoms of dementia (BPSD) are not merely an epiphenomenon of cognitive impairment, but could be attributed to specific biological brain dysfunction. We describe findings from different research modalities related with BPSD (psychopathological, neuropsychological, neurochemical, and psychophysiological strategies), and attempt to reconcile them into the more integrated form. Characteristics of delusions in dementia patients should be studied in more detail from a psychopathological aspect, aiming for the integration of psychopathology and neurobiology. Imperfect integration of memory function and cognitive function, assigned to the limbic systems and association areas, respectively, may result in BPSD. More intimate collaboration of psychopathological and neurobiological study would be fruitful to promote the research in psychological basis of BPSD. Neurochemical studies indicated that density of extracellular tangles and/or PHF-tau protein have relationships with delusion or misidentification. These changes in neurochemical parameters should be the key to understanding the pathogenesis of BPSD. More importantly, neurochemical and psychological study could be linked by the research in psychophysiology. Computer-assisted electroencephalogram analysis suggests that the right posterior hemisphere shows significant age-associated change earlier than the left in the elderly. Cerebral metabolic rate by positron emission tomography study indicates that paralimbic, left medial temporal, and left medial occipital area are involved in pathogenesis of BPSD in some dementia patients. [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] Dissociated effects of diazepam and lorazepam on short-latency afferent inhibitionTHE JOURNAL OF PHYSIOLOGY, Issue 1 2005Vincenzo Di Lazzaro Peripheral nerve inputs have an inhibitory effect on motor cortex excitability at short intervals (short-latency afferent inhibition, SAI). This can be tested by coupling electrical stimulation of peripheral nerve with transcranial magnetic stimulation (TMS) of the motor cortex. SAI is reduced by the anticholinergic drug scopolamine, and in patients with Alzheimer's disease. Therefore, it is possible that SAI is a marker of central cholinergic activity important for memory function. The benzodiazepine lorazepam also reduces SAI. Since benzodiazepines impair memory formation, but do not do so uniformly, with a maximum amnesic effect after lorazepam but less or no effect after diazepam, we were interested in testing in this non-behavioural study to what extent the effects of lorazepam and diazepam on circuits involved in SAI could be dissociated. In addition, and for control, we tested the effects of lorazepam and diazepam on short-interval intracortical inhibition (SICI), a motor cortical inhibition mediated through the GABAA receptor. Lorazepam markedly reduced SAI, whereas diazepam slightly increased it. In contrast, both benzodiazepines uniformly increased SICI. Our findings demonstrate opposite effects of lorazepam and diazepam on SAI, an inhibition modulated by central cholinergic activity, but the same effects on SICI, a marker of neurotransmission through the GABAA receptor. This dissociation suggests, for the first time, that TMS measures of cortical inhibition provide the opportunity to segregate differences of benzodiazepine action in human central nervous system circuits. [source] Role of interleukin-1, in postoperative cognitive dysfunctionANNALS OF NEUROLOGY, Issue 3 2010Mario Cibelli MD Objective: Although postoperative cognitive dysfunction (POCD) often complicates recovery from major surgery, the pathogenic mechanisms remain unknown. We explored whether systemic inflammation, in response to surgical trauma, triggers hippocampal inflammation and subsequent memory impairment, in a mouse model of orthopedic surgery. Methods: C57BL/6J, knock out (lacking interleukin [IL]-1 receptor, IL-1R,/,) and wild type mice underwent surgery of the tibia under general anesthesia. Separate cohorts of animals were tested for memory function with fear conditioning tests, or euthanized at different times to assess levels of systemic and hippocampal cytokines and microglial activation; the effects of interventions, designed to interrupt inflammation (specifically and nonspecifically), were also assessed. Results: Surgery caused hippocampal-dependent memory impairment that was associated with increased plasma cytokines, as well as reactive microgliosis and IL-1, transcription and expression in the hippocampus. Nonspecific attenuation of innate immunity with minocycline prevented surgery-induced changes. Functional inhibition of IL-1,, both in mice pretreated with IL-1 receptor antagonist and in IL-1R,/, mice, mitigated the neuroinflammatory effects of surgery and memory dysfunction. Interpretation: A peripheral surgery-induced innate immune response triggers an IL-1,-mediated inflammatory process in the hippocampus that underlies memory impairment. This may represent a viable target to interrupt the pathogenesis of postoperative cognitive dysfunction. ANN NEUROL 2010;68:360,368 [source] Cognition, reserve, and amyloid deposition in normal agingANNALS OF NEUROLOGY, Issue 3 2010Dorene M. Rentz PsyD Objective To determine whether amyloid deposition is associated with impaired neuropsychological (NP) performance and whether cognitive reserve (CR) modifies this association. Methods In 66 normal elderly controls and 17 patients with Alzheimer disease (AD), we related brain retention of Pittsburgh Compound B (PiB) to NP performance and evaluated the impact of CR using education and American National Adult Reading Test intelligence quotient as proposed proxies. Results We found in the combined sample of subjects that PiB retention in the precuneus was inversely related to NP performance, especially in tests of memory function, but also in tests of working memory, semantic processing, language, and visuospatial perception. CR significantly modified the relationship, such that at progressively higher levels of CR, increased amyloid deposition was less or not at all associated with poorer neuropsychological performance. In a subsample of normal controls, both the main effect of amyloid deposition of worse memory performance and the interaction with CR were replicated using a particularly challenging memory test. Interpretation Amyloid deposition is associated with lower cognitive performance both in AD patients and in the normal elderly, but the association is modified by CR, suggesting that CR may be protective against amyloid-related cognitive impairment. ANN NEUROL 2010;67:353,364 [source] Hippocampal interictal spikes disrupt cognition in ratsANNALS OF NEUROLOGY, Issue 2 2010Jonathan K. Kleen BS Objective Cognitive impairment is common in epilepsy, particularly in memory function. Interictal spikes (IISs) are thought to disrupt cognition, but it is difficult to delineate their contribution from general impairments in memory produced by etiology and seizures. We investigated the transient impact of focal IISs on the hippocampus, a structure crucial for learning and memory and yet highly prone to IISs in temporal lobe epilepsy (TLE). Methods Bilateral hippocampal depth electrodes were implanted into 14 Sprague-Dawley rats, followed by intrahippocampal pilocarpine or saline infusion unilaterally. Rats that developed chronic spikes were trained in a hippocampal-dependent operant behavior task, delayed-match-to-sample. Depth-electroencephalogram (EEG) was recorded during 5,562 trials among five rats, and within-subject analyses evaluated the impact of hippocampal spikes on short-term memory operations. Results Hippocampal spikes that occurred during memory retrieval strongly impaired performance (p < 0.001). However, spikes that occurred during memory encoding or memory maintenance did not affect performance in those trials. Hippocampal spikes also affected response latency, adding approximately 0.48 seconds to the time taken to respond (p < 0.001). Interpretation We found that focal IIS-related interference in cognition extends to structures in the limbic system, which required intrahippocampal recordings. Hippocampal spikes seem most harmful if they occur when hippocampal function is critical, extending human studies showing that cortical spikes are most disruptive during active cortical functioning. The cumulative effects of spikes could therefore impact general cognitive functioning. These results strengthen the argument that suppression of IISs may improve memory and cognitive performance in patients with epilepsy. ANN NEUROL 2010;67:250,257 [source] A comparison of working memory skills and learning in children with developmental coordination disorder and moderate learning difficultiesAPPLIED COGNITIVE PSYCHOLOGY, Issue 4 2007Tracy Packiam Alloway The present study compared 6,11 years old with developmental coordination disorder (DCD) and those with moderate learning difficulties (MLD) on measures of memory (verbal short-term and working memory, visuo-spatial short-term and working memory), literacy and numeracy, and IQ. The findings indicate that children with DCD appear to be impaired in all four areas of memory function; in particular they performed at significantly lower levels than children with MLD in measures of verbal short-term memory, visuo-spatial short-term and working memory. In contrast, performance of children with MLD in the memory measures was within age-expected levels, with deficits observed only in verbal working memory tasks. There were also differential links between memory and attainment between the two groups, and these were significant even after statistically accounting for the contribution of IQ. Reasons for why working memory contributes to learning in these two developmental groups are discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source] A Novel Cyclic Squamosamide Analogue Compound FLZ Improves Memory Impairment in Artificial Senescence Mice Induced by Chronic Injection of D-Galactose and NaNO2BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2007Fang Fang Artificially senescent mouse model was induced by consecutive injection of D-galactose (120 mg/kg) and NaNO2 (90 mg/kg) once daily for 60 days. Compound FLZ (75 and 150 mg/kg) was orally administered once daily for 30 days after D-galactose and NaNO2 injection for 30 days. The water maze test was used to evaluate the learning and memory function of mice. The content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum were determined using different biochemical kits. The alterations in hippocampus morphology were assessed by light and electronic microscope. Immunoreactive cells of Bcl-2 in the hippocampus were counted by immunohistochemical staining, and Bcl-2 protein expression was analysed by Western blot method. The results indicate that injection of D-galactose and NaNO2 induces memory impairment and neuronal damage in hippocampus of mice. In addition, serum SOD and GSH-Px activities decreased, while MDA level increased. Bcl-2-positive neurons and Bcl-2 protein expression in the hippocampus decreased remarkably. Oral administration of FLZ for 30 days significantly improved the cognitive deficits and the biochemical markers mentioned above, and also reduced the pathological alterations in mouse hippocampus. The results suggest that FLZ ameliorates memory deficits and pathological injury in artificially senescent mice induced by chronic injection of D-galactose and NaNO2, indicating that FLZ is worth further studies for fighting antisenescence and dementia. [source] Memory functioning in familial bipolar I disorder patients and their relativesBIPOLAR DISORDERS, Issue 2 2009Seema Quraishi Objective:, The aim of this study was to compare the memory function of patients with familial bipolar I disorder (BD I) who had shown psychotic features, their non-psychotic, non-bipolar first-degree relatives, and normal controls. Method:, We assessed 38 patients with a lifetime diagnosis of BD I who had experienced psychotic symptoms, 49 of their non-psychotic, non-bipolar first-degree relatives, and 44 controls. Patients and relatives were from families multiply affected with functional psychotic illness. A five-subtest short form of the Wechsler Adult Intelligence Scale,Revised and three Wechsler Memory Scale subtests were administered to all participants. Results:, BD I patients showed deficits in verbal memory and verbal learning but not in visual memory. Compared to controls, relatives showed worse verbal learning at a statistically significant or suggestive level and performed significantly worse in both immediate and delayed verbal memory. Similar to patients, there were no differences between the relatives and control group for visual memory. Conclusion:, Impaired verbal memory and learning were found in patients and their relatives. These deficits may represent candidate endophenotypic markers for bipolar disorder. [source] [Gly14]-Humanin improved the learning and memory impairment induced by scopolamine in vivoBRITISH JOURNAL OF PHARMACOLOGY, Issue 8 2001Takayoshi Mamiya Humanin is a very recently discovered 24 amino acid linear polypeptide, which protects against cell death induced by either familial Alzheimer's disease mutant of amyloid precursor protein, presenilin-1 or presenilin-2 in vitro. However, it has remained uncertain whether humanin is a useful drug for the animal model of learning and memory deficit. In this study, we evaluated the effects of [Gly14]-humanin, a more potent humanin analogue, on the scopolamine HBr (1 mg kg,1 s.c.)-induced impairment of spontaneous alternation behaviour in the Y-maze, an index of short-term memory in mice. [Gly14]-Humanin (1000 pmol 5 ,l,1 i.c.v.) reversed the impairment without affecting the number of arm entries. These results suggest that (I) [Gly14]-humanin is a beneficial drug for the impairment of learning and memory and (II) it modulates the learning and memory function mediated via cholinergic systems in mice. British Journal of Pharmacology (2001) 134, 1597,1599; doi:10.1038/sj.bjp.0704429 [source] A case of Kleine,Levin syndrome examined with SPECT and neuropsychological testingACTA NEUROLOGICA SCANDINAVICA, Issue 4 2002A.-M. Landtblom A case of Kleine,Levin syndrome with typical periodic hypersomnia and bulemia was diagnosed. On examination with single photo emission tomography (SPECT) (CERETEC®) during a relapse period and 2 weeks later there was marked cortical hypoperfusion of the frontal and temporal lobes, especially on the left side as well as in the right parietal lobe. Neuropsychological testing performed 1 week after a relapse showed a reduction in encoding to memory function of verbal learning indicating neocortical damage of the left fronto-temporal region. A follow-up 2 months later after the patient had spontaneously recovered showed only a slight left fronto-temporal disturbance. CT and MRI of the brain were normal although the MRI showed a large and asymmetric mamillary body. Neuropsychological testing 6 years after recovery showed pronounced reduction in short-time verbal and visual memory. Seven years after recovery SPECT demonstrated a normalized frontal perfusion but still a slight hypoperfusion in the left temporal lobe. Our results correlate to autopsy findings in two cases described previously. [source] | ||||||||||||||||||||||||||||||||||