SEARCH · PubMed Health

Results for “Memory”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources

PubMed2001

Normal spatial memory following postseizure treatment with ketamine: selective damage attenuates memory deficits in brain-damaged rodents.

Within 30 min after the initiation of status epilepticus (SE) by lithium and pilocarpine, rats were injected with either acepromazine or ketamine. Compared to the rats that had received the acepromazine, the group that had received the ketamine displayed more accurate spatial memory. Their scores did not differ significantly from normal (non-seized) controls. Although the ketamine treatment did not significantly change the amount of neuronal loss within about 100 Paxinos and Watson structures, it was neuroprotective for several structures within the thalamus and portions of the temporal and parietal cortices. Ketamine-treated rats, however, displayed markedly more damage within the entorhinal cortices and amygdalohippocampal area.

Acepromazine↗

PubMed2006

Unidirectional development of CD8+ central memory T cells into protective Listeria-specific effector memory T cells.

Three distinct subsets of antigen-experienced CD8(+) T cells have been identified so far: short-living effector T cells (T(EC)) and two long-living subsets, described as central (T(CM)) and effector memory (T(EM)) T cells. The lineage relationships of these subpopulations as well as their involvement in protection have not yet been conclusively determined. We recently described a novel marker combination (CD127 and CD62L) to identify all three major CD8(+) T cell subsets in mice infected with Listeria monocytogenes (L.m.). Extensive lineage relationship analyses on highly purified subpopulations after in vitro and in vivo stimulation demonstrated that T(CM) can develop into T(EM) or T(EC), whereas T(EM) can only progress to T(EC) cells. Short-living T(EC) never regained a T(EM) or T(CM) phenotype. These data strongly suggest a hierarchical and unidirectional order of developmental stages. In vivo priming protocols that preferentially induced one of the different CD8(+) T cell subsets demonstrated that predominance of T(EM) (CD40 stimulation) correlated best with effective protection against L.m., whereas generation of neither T(CM) (by immunization with heat-killed L.m.) nor T(EC) (by systemic co-administration of CpG during primary infection) conferred substantial long-term protective immunity. These findings have important implications for the design of more effective T cell-based vaccines.

Animals↗

PubMed1990

Similar memory impairments found in medial septal-vertical diagonal band of Broca and nucleus basalis lesioned rats: are memory defects induced by nucleus basalis lesions related to the degree of non-specific subcortical cell loss?

The function of nucleus basalis (NB) and medial septal-vertical diagonal band of Broca (MS-VDBB) in a place navigation task requiring reference memory was investigated. Two subclasses of nucleus basalis ibotenic acid-lesioned rats could be identified: a group having both extensive non-specific subcortical damage and severely impaired learning behavior, and a less impaired group with correspondingly less subcortical damage. The depletion of cortical cholinergic enzymes was slightly higher in the group of NB-lesioned rats with extensive subcortical lesions than in the group with smaller lesioned areas. In the hippocampus of both of these NB-lesioned groups, cholinergic innervation remained unchanged. Ibotenic acid lesioning restricted to the MS-VDBB depleted hippocampal cholinergic innervation, but not the innervation of the frontal cortex, and also led to impaired learning behavior. Of all the lesioned rats, the most impaired were the NB-lesioned rats with large non-specific subcortical lesion.

Acetylcholinesterase↗

PubMed1989

Memory for internally generated words in Alzheimer-type dementia: breakdown in encoding and semantic memory.

The "generation effect" is a phenomenon in which words that are generated by the subject are remembered better than words which are read. The present experiments examined this effect in patients with mild-to-moderate dementia of the Alzheimer type (DAT), healthy elderly adults, and young adults under a variety of different encoding and retrieval conditions. Experiment 1 employed an intentional learning task with multiple study/test trials using the same list of words. While both the young and elderly adults exhibited higher recall for internally generated words than read words, the DAT patients failed to demonstrate the effect even after repeated exposures to the same stimulus list. Experiment 2 replicated this same pattern of results using an incidental learning paradigm with both recall and recognition tests. Various explanations as to why the DAT patients failed to show the generation effect were discussed with particular emphasis placed on the role of semantic memory and encoding failure.

Adult↗

PubMed2006

Evidence against memorial facilitation and context-dependent memory effects through the chewing of gum.

The experiment examined the prediction that chewing gum at learning and/or recall facilitated subsequent word recall. Chewing gum at learning significantly impaired recall, indicating that the chewing of gum has a detrimental impact upon initial word encoding. In addition, a context-dependent memory effect was reported for those participants who both learned and recalled in the absence of gum; however, a context-dependent effect was not found with chewing gum. The findings contradict previous research.

Adult↗

PubMed2004

Genes and memory: the neuroanatomical correlates of emotional memory in monozygotic twin discordant for schizophrenia.

BACKGROUND: Brain morphology and physiological measures in schizophrenia have yielded inconsistent results. This may be due in part to difficulties in ascertaining precisely to what degree each measure deviates from its genetically and environmentally determined potential level. We attempted to surmount this problem in a paradigm involving monozygotic twin pair discordant for schizophrenia. In this paradigm, the difference score and reaction time between the unaffected member and affected member of a twin pair should represent the degree of pathologic involvement irrespective of actual level. METHOD: We investigated, using fMRI, the neural substrate underlying encoding and retrieval of aversive and neutral IAPS pictures. RESULTS: An ANOVA on reaction time (RT) between schizophrenia patient (J) and normal sister (D) significant difference, (F = 5.2, p < or = .02) for J had less RT than D. Conversely, the ANOVA for the correct pictures retrieved was insignificant (F = 1.8, p < or = .2). When the brain activity associated with the encoding and retrieval of the aversive pictures was subtracted (J-D and D-J) from that associated with the neutral ones, significant loci of activation were found. During encoding: for J-D the right fusiform gyrus was significantly activated (p < .0001) and for D-J the orbitofrontal cortex was significantly activated (p < .05). During retrieval: for J-D the right anterior cingulate (p < .0001) was activated and the dorsolateral prefrontal cortex (p < .002). For D-J only the cerebellum showed activation (p < .0001). CONCLUSION: Results indicated subtle attenuations in some aspects of memory, thus providing another evidence for cognitive markers of a genetic component in schizophrenia. New approaches in neuropsychiatry-based on genetic methodologies should further define the cerebral physiology responsible for schizophrenia.

Adult↗

PubMed2006

Spontaneous behavior of a rhesus monkey (Macaca mulatta) during memory tests suggests memory awareness.

Humans can predict with some accuracy whether or not they know the correct answer to a question before responding. In some cases the capacity to make such predictions depends on memory awareness, the ability to introspectively discriminate between knowing and not knowing. In this unplanned retrospective analysis of video taped behavior we asked whether a rhesus monkey's apparent frustration predicted his accuracy in a matching-to-sample task on a trial-by-trial basis. The monkey was likely to aggressively strike the computer touchscreen when committing errors, whereas he generally touched the screen more gently when selecting the correct stimulus. This difference in behavior, which occurred before the monkey received feedback on the accuracy of his choice, suggests that he knew whether or not he remembered the correct response.

Aggression↗

PubMed2005

Two spatial memories are not better than one: evidence of exclusivity in memory for object location.

This paper studies the dynamics of attempting to access two spatial memories simultaneously and its implications for the accuracy of recall. Experiment 1 demonstrates in a range of conditions that two cues pointing to different experiences of the same object location produce little or no higher recall than that observed with a single cue. Experiment 2 confirms this finding in a within-subject design where both cues have previously elicited recall. Experiment 3 shows that these findings are only consistent with a model in which two representations of the same object location are mutually exclusive at both encoding and retrieval, and inconsistent with models that assume information from both representations is available. We propose that these representations quantify directionally specific judgments of location relative to specific anchor points in the stimulus; a format that precludes the parallel processing of like representations. Finally, we consider the apparent paradox of how such representations might contribute to the acquisition of spatial knowledge from multiple experiences of the same stimuli.

Cues↗

PubMed2006

Animal memory: episodic-like memory in rats.

Recent experiments with rats on a radial maze indicate that they can remember what foods they encountered, and when and where they encountered them. These findings, and others with food-storing birds, challenge the idea that only humans have episodic memory.

Animals↗

PubMed1992

Sleep and memory. I: The influence of different sleep stages on memory.

A new approach to the sleep stages role in memory is discussed in the context of the two opposite patterns of behavior-search activity and renunciation of search. Search activity is activity designed to change the situation (or the subjects attitudes to it) in the absence of a definite forecast of the results of such activity, but with the constant consideration of these results at all stages of activity. Search activity increases general adaptability and body resistance while renunciation of search decreases adaptability and requires REM sleep for its compensation. Unprepared learning, which is often accompanied by failures on the first steps of learning, is suggested to produce renunciation of search, which decreases learning ability, suppress retention, and increase REM sleep requirement. A prolonged REM sleep deprivation before training causes learned helplessness and disturbs the learning process, while short REM sleep deprivation cause the "rebound" of the compensatory search activity that interferes with passive avoidance. REM sleep deprivation performed after a training session can increase distress caused by a training procedure, with the subsequent negative outcome on retention.

Animals↗

PubMed2003

Can memory be improved? A discussion on the role of ras, GABA, acetylcholine, NO, insulin, TNF-alpha, and long-chain polyunsaturated fatty acids in memory formation and consolidation.

It is proposed that long-chain polyunsaturated fatty acids when given from the perinatal period will ensure proper development and growth of the brain and maintain the activity and/or concentrations of ras, nitric oxide, insulin, and various neurotransmitters and cytokines at physiological level and thus, improve memory and prevent learning deficits.

Acetylcholine↗

PubMed1998

Memory: dissociating multiple memory processes.

Memory depends upon a network of interconnected and functionally related cortical and subcortical areas including, at the very least, the prefrontal cortex and the medial temporal lobe structures. Evidence is now emerging to relate these neuroanatomical regions to specific aspects of mnemonic processing.

Animals↗

PubMed1985

Memory deficits and memory surfeits: differential cognitive consequences of tokenism for tokens and observers.

Historically, women and minority group members have been underrepresented in the professions and in better paying, high-status jobs. Even when they have been admitted to such positions, these underrepresented persons often have been the only member of their social category: a token. Previous field and laboratory research has shown that "tokens" attract disproportionate attention and are either evaluated unfairly or evaluated on the basis of their normal reactions to differential treatment by majority group members. We tested the possibilities of whether tokens might suffer more cognitive deficits than would nontokens, and whether they do so even when they are treated no differently. College students were led to believe that they were sharing their views on everyday topics with three other students (actually videotaped confederates), who were either all of the student's own sex or all of the opposite sex. In a later memory test, token participants remembered fewer of the opinions that they and the three other students had expressed than did nontokens. Observers, in contrast, remembered more of what token subjects said than what the three other students said. Theoretical and public policy implications are discussed.

Attention↗

PubMed2006

All updateable objects in working memory are updated whenever any of them are modified: evidence from the memory updating paradigm.

In a series of experiments, participants were required to keep track of 1 or 2 working memory (WM) objects, having to update their values in 80% of the trials. Updating cost, defined as the difference between update and non-update trials, was larger when 2 objects were involved compared with when there was only 1 object was involved. This finding was interpreted as evidence that the updating process encompasses both objects in WM, even though only 1 of them is actually updated. This feature of WM updating is limited to objects defined as "updateable," throughout the trial sequence. The results are explained by the need to reprogram the phonological loop when updating or the need for desynchronization followed by resynchronization of WM contents.

Adult↗

PubMed1984

Suppressor T cell memory. Induction and recall of HGG-specific memory suppressor T cells and their role in regulation of antibody production.

Regulation of the antibody response to the hapten, dinitrophenyl (DNP), was studied using human gammaglobulin (HGG) as the carrier in an adoptive transfer system. CBA mice immunized at least 4 weeks previously to HGG or DNP served as the source of T helper cells and hapten-primed B cells, respectively. The addition of spleen cells from donors recently primed to HGG in immunogenic form (aHGG) suppressed the collaborative anti-DNP PFC response as effectively as cells from tolerant donors. The suppressive effect was antigen-specific and was mediated by a T cell with the same phenotype (Ly-1-, Ly-23+, Ia+) and induction kinetics as those previously identified in HGG-tolerant animals. During the primary response to HGG an early burst of helper activity was detected initially, followed by a wave of suppression which peaked at day 7 and subsequently waned, allowing adoptive helper function to reappear during the third week. When previously immunized animals were boosted with soluble HGG after primary suppression had waned, the sequential appearance of helper and suppressor activity was accelerated, and the secondary suppressive effect was more profound and of longer duration than that observed during a primary response. Although helper activity was not apparent during the peak of secondary suppression, helper T cells (Th) had not been functionally deleted since treatment of the donor spleen cells with anti-Ia and complement to deplete suppressor T cells (Ts) before adoptive transfer resulted in significant augmentation of the anti-DNP response. The secondary suppressive effect was formally shown to be mediated by activated Ts effector cells bearing the same surface markers as the cells responsible for primary suppression. The results suggest that the Ts population, like other lymphocyte subsets, contain memory cells capable of rapid reexpression of effector function upon secondary exposure to antigen. These cells are considered to be of a major importance in maintenance of immune homeostasis.

Animals↗

PubMed1980

Memory neuron: synapse microchemistry for the memory component of a neuroconnective brain model.

This paper examines the synaptic microchemistry required if a memory neuron is to have the operating characteristics previously attributed to it [Wooldridge, D.E. (1980) Proc. Natl. Acad. Sci. USA, 77,2305-2308]. It is concluded that the requirements can be met by a combination of membrane mechanisms not very different from those that are commonly postulated to explain the properties of known types of neurons.

Brain↗

PubMed1989

Assessing memory deterioration with the Wechsler Memory Scale, the National Adult Reading Test, and the Schonell Graded Word Reading Test.

The National Adult Reading Test (NART), the Schonell Graded Word Reading Test (SGWRT), and the Wechsler Memory Scale, Form I (WMS) were administered to 65 healthy subjects aged 65 to 89 years. Regression equations were derived which allowed total raw score on the WMS to be predicted from the subject's age and from the number of errors on the NART alone or on the NART and SGWRT combined. The distribution of discrepancies between obtained and predicted WMS scores for each equation did not depart significantly from normality and the percentage of subjects at each discrepancy score is provided. The standard error of prediction for each equation is slightly less than that for predicting WAIS IQ from the NART. Sixteen patients with clinical diagnoses of senile dementia of the Alzheimer type obtained discrepancies as large or larger than the most discrepant 2% of normal subjects. These results suggest that this procedure may provide a brief but effective assessment of cognitive deterioration in the elderly and may be capable of assessing dementia earlier than the NART/WAIS combination.

Aged↗

PubMedDate not supplied

The relationship between short-term memory and working memory: complex span made simple?

This experiment addresses the question of what makes a working memory measure a good predictor of higher-level abilities. Verbal and visuospatial processing episodes were interleaved with distinct verbal and visuospatial storage episodes to form four complex span tasks. Although these measures were reliable predictors of reading and mathematics ability in children, they were no more predictive of these abilities than corresponding simple span tasks involving storage alone. However, when individual differences in storage ability and processing capacity were controlled for, residual variance in complex span performance was related to academic ability in some cases. These findings indicate that complex span tasks are multiply determined, and that differences in task structure can dramatically influence the relative importance of these multiple constraints and the predictive power of a complex span measure.

Child↗