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PubMed1983

Generation of immune memory by haptenated derivatives of thymus-independent antigens in C57BL/6 mice. I. The differentiation of memory B lymphocytes into antibody-secreting cells depends on the nature of the thymus-independent carrier used for memory induction and/or revelation.

It has been previously reported that trinitrophenylated lipopolysaccharide (TNP-LPS), a thymus-independent (TI)-1 antigen, elicits an anamnestic response to TNP in C57BL/6 mice. The ability of these mice to mount a secondary response to TI-2 antigens was analyzed. Priming with DNP-Ficoll or DNP-Dextran, both TI-2 antigens, resulted in an increased frequency of TNP-binding B lymphocytes. Evidence is presented that memory cell-induction by DNP-Ficoll does not require functional T cells. The differentiation into antibody-forming cells (AFC) of memory cells generated by DNP-Dextran or DNP-Ficoll cannot be obtained by a challenge with either antigen. There was no indication that the lack of a secondary response to TI-2 antigens was related to suppressive T cells interfering with memory expression. Memory cells induced by DNP-Dextran or DNP-Ficoll can nevertheless be activated by TNP-LPS. In contrast to the restricted sensitivity of TNP-memory cells generated by TI-2 antigens, TNP-LPS-induced memory cells are indifferently susceptible to TI-1 or TI-2 antigenic stimulation. These results are discussed in terms of memory B-cell subpopulations.

Animals↗
PubMed1984

Immediate memory span, recognition memory for subspan series of words, and serial position effects in recognition memory for supraspan series of verbal and nonverbal items in Broca's and Wernicke's aphasia.

Four Broca's aphasics, four Wernicke's aphasics, and four matched controls were investigated on three verbal and one visual short-term memory tasks. Experiment 1 considered memory span and subspan recognition memory for verbal items and Experiment 2 assessed serial position effects in supraspan verbal recognition memory. The Broca's aphasics demonstrated verbal memory deficits, which could not be attributed to linguistic disturbances, while the verbal memory deficiencies seen with the Wernicke's aphasics could be regarded as secondary to linguistic defects. In Experiment 3, where visual recognition memory was investigated, only the Broca's aphasics showed deficient performance. The wider context of deficient mnemonic performance in aphasia is discussed.

Aged↗
PubMedDate not supplied

Using a memory handbook to improve everyday memory in community-dwelling older adults with memory complaints.

Community-dwelling, nondemented older people (60-70 years) with reported memory complaints were randomly assigned to either a memory-handbook (MHB) group (n = 20) or a placebo group (n = 20). The MHB group members were given a self-contained memory handbook and were individually trained on two of the handbook's sections that related to (a) remembering a person's name and (b) prospective memory, for approximately 30 minutes each. The placebo group was given an instructional pamphlet with a description of three list-learning mnemonics as a placebo treatment. Subjects were tested before and after the intervention. When compared with the placebo group, the MHB group members significantly improved their performance on a face-naming task and a strategies knowledge questionnaire, but not on the prospective memory measures, when compared with the placebo group. In addition, the MHB group showed a significant advantage on an everyday memory diary that was filled out by all subjects following the intervention. Following the study, the placebo group was also given the memory handbook, and both groups were then assessed on their knowledge and use of strategies by questionnaire at a 4-month follow-up. At this time the MHB group appeared to maintain most of its original gains, while the placebo group made some improvement.

Aged↗
PubMed2004

What's in a name for memory errors? Implications and ethical issues arising from the use of the term "false memory" for errors in memory for details.

The term "false memories" has been used to refer to suggestibility experiments in which whole events are apparently confabulated and in media accounts of contested memories of childhood abuse. Since 1992 psychologists have increasingly used the term "false memory" when discussing memory errors for details, such as specific words within lists. Use of the term to refer to errors in details is a shift in language away from other terms used historically (e.g., "memory intrusions"). We empirically examine this shift in language and discuss implications of the new use of the term "false memories." Use of the term presents serious ethical challenges to the data-interpretation process by encouraging over-generalization and misapplication of research findings on word memory to social issues.

Adult↗
PubMed2000

Assessing subtle memory impairments in the everyday memory performance of brain injured people: exploring the potential of the extended Rivermead Behavioural Memory Test.

A substantial number of brain injured patients complain of memory deficits, despite achieving scores within the normal range on tests of memory functioning. The Rivermead Behavioural Memory Test is an ecologically valid test used to assess everyday memory problems. This test is effective at detecting moderate to-severe impairments, yet subtle memory deficits may go undetected for some patients who achieve a score within the normal range. The initial development of an extended version of this test (RBMT-E), designed to detect subtle decrements in memory performance, has recently been described. The performance of 16 brain injured patients was assessed on both the RBMT and the KBMT-E. The performance of these patients on the RBMT-E was compared with that of matched controls. Overall, the patients performed significantly worse than the controls, and showed particular difficulty in two subtests involving recalling a route and remembering to deliver a message. Those patients who scored in the 'normal' range on the RBMT could be further differentiated on the basis of their RBMT-E scores into 'good', 'average' and 'poor' performance categories. The patients' performance was not significantly associated with general intellectual ability. These results suggest that the RBMT-E may be a useful clinical tool to aid therapists in the assessment of subtle impairments of everyday memory performance following brain injury.

Adolescent↗
PubMed2003

Common prefrontal activations during working memory, episodic memory, and semantic memory.

Regions of the prefrontal cortex (PFC) are typically activated in many different cognitive functions. In most studies, the focus has been on the role of specific PFC regions in specific cognitive domains, but more recently similarities in PFC activations across cognitive domains have been stressed. Such similarities may suggest that a region mediates a common function across a variety of cognitive tasks. In this study, we compared the activation patterns associated with tests of working memory, semantic memory and episodic memory. The results converged on a general involvement of four regions across memory tests. These were located in left frontopolar cortex, left mid-ventrolateral PFC, left mid-dorsolateral PFC and dorsal anterior cingulate cortex. These findings provide evidence that some PFC regions are engaged during many different memory tests. The findings are discussed in relation to theories about the functional contribution of the PFC regions and the architecture of memory.

Adult↗
PubMed2001

Independent regulation of lymphocytic choriomeningitis virus-specific T cell memory pools: relative stability of CD4 memory under conditions of CD8 memory T cell loss.

Infection of mice with a series of heterologous viruses causes a reduction of memory CD8(+) T cells specific to viruses from earlier infections, but the fate of the virus-specific memory CD4(+) T cell pool following multiple virus infections has been unknown. We have previously reported that the virus-specific CD4(+) Th precursor (Thp) frequency remains stable into long-term immunity following lymphocytic choriomeningitis virus (LCMV) infection. In this study, we questioned whether heterologous virus infections or injection with soluble protein CD4 Ags would impact this stable LCMV-specific CD4(+) Thp memory pool. Limiting dilution analyses for IL-2-producing cells and intracellular cytokine staining for IFN-gamma revealed that the LCMV-specific CD4(+) Thp frequency remains relatively stable following multiple heterologous virus infections or protein Ag immunizations, even under conditions that dramatically reduce the LCMV-specific CD8(+) CTL precursor frequency. These data indicate that the CD4(+) and CD8(+) memory T cell pools are regulated independently and that the loss in CD8(+) T cell memory following heterologous virus infections is not a consequence of a parallel loss in the memory CD4(+) T cell population.

Acute Disease↗
PubMed1997

Vasopressin and memory. I. The vasopressin analogue AVP4-9 enhances working memory as well as reference memory in the radial arm maze.

The present study examined the effects of vasopressin on memory. Healthy rats were injected with the arginine vasopressin fragment AVP4-9 and the AVP antagonist [beta-mercapto-beta,beta-cyclopentamethylenepropionyl1,O-Et-Pyr 2,Val4,Arg8] and were tested in an eight-arm radial maze for 60 sessions. All injections were given s.c. 30 min prior to testing. AVP4-9 enhanced radial arm maze performance. AVP4-9 treated animals showed enhancement in performance as well as increases in the rate of learning, indicating that they learned the task faster. Furthermore, the overall memory enhancement was due to improved working memory as well as to improved reference memory. These results cannot be explained in terms of changes in locomotor activity because an open field test revealed no differences between groups for both of these compounds. The AVP antagonist did not impair performance in the radial maze. It is concluded that AVP4-9 has a more general effect on memory, one that is not limited to a specific type of memory.

Animals↗
PubMed2001

[Neural basis of spatial orientation and memory of routes: topokinetic memory or topokinesthesic memory].

The neural basis of spatial orientation and the memory of routes have been explored by brain imaging (PET SCAN and fMRI) in human. Several cognitive strategies and several types of reference frames can be used by the brain to establish relations between our body and the environment. Four categories of brain areas have been considered: the areas involved in egocentric and allocentric coding on one hand and on the other hand the areas involved in the "route" like and the "survey or map" like strategies used during tasks in which subjects had to mentally remember a path by mental navigation or mental scanning of a map. The results have confirmed that parietal and frontal structures involved in "spatial neglect" are also found to be involved in the egocentric orientation tasks of subjective midline detection. More generally we have been able to identify parieto-frontal areas involved in visuo-spatial memory. In addition we have identified the areas involved in the cortical processing of vestibular information and lastly we have shown that in addition to the parieto-frontal areas a parieto temporal lobe network is involved in allocentric tasks and also during mental navigation by route or survey strategies. These results contribute to the identification of the neural basis of topographic memory but they also suggest that we have to define a particular type of spatial memory which is involved in the memory of routes and movements which we suggest to call "topo-kinetic" or "topo-kinesthetic" memory.

Brain Mapping↗
PubMed1991

Sex differences in spatial memory: a reanalysis of block tapping long-term memory according to the short-term memory level.

This paper analyzes the spatial memory performance of 495 subjects. Both short-term and long-term memory have been analyzed by means of the Corsi block-tapping test. We provide separate norms for the learning of a supra-span sequence according to the level of spatial short-term memory. The long-term memory of males and females was compared in groups matched for spatial short-term memory, and the gender effect was never found to be significant. This finding is discussed in relation to the nature of sex differences in spatial abilities.

Educational Status↗
PubMed2005

BGC20-761, a novel tryptamine analog, enhances memory consolidation and reverses scopolamine-induced memory deficit in social and visuospatial memory tasks through a 5-HT6 receptor-mediated mechanism.

Inhibition of 5-HT(6) receptors has been shown to improve memory consolidation, thus we tested whether a novel tryptamine analog with high affinity for 5-HT(6) receptors, BGC20-761 (5-methoxy-2-phenyl-N,N-dimethyltryptamine, PMDT), can enhance long-term memory. BGC20-761 (10 mg/kg i.p.) alone had no effect on social recognition in young rats, however, at doses of 5 mg/kg and 10 mg/kg i.p, BGC20-761 dose-dependently reversed a deficit of social recognition induced by scopolamine (0.4 mg/kg i.p.), an anticholinergic drug that impairs memory. BGC20-761 (10 mg/kg i.p.), scopolamine (0.2 mg/kg i.p.) or BGC20-761 + scopolamine had no effects on novel object discrimination in young rats (2 months). In mature rats (6 months), recognition of the novel object was improved following administration of BGC20-761. Scopolamine had no effect in object recognition. However, the addition of scopolamine disrupted the memory-enhancing effect of BGC20-761. Based on the high affinity of BGC20-761 for 5-HT(6) receptors, these cognitive enhancing effects are most likely mediated by 5-HT(6) receptor inhibition. The difference in effects of BGC20-761 in young vs. mature rats may reflect the status of memory consolidation in these different age ranges.

Animals↗
PubMed2005

Sulpiride and mnemonic function: effects of a dopamine D2 receptor antagonist on working memory, emotional memory and long-term memory in healthy volunteers.

There is now substantial evidence from animal studies showing modulation of cognitive performance after administration of dopaminergic agents. Previous studies have focused on cognitive functions such as working memory (WM), with particular reference to spatial processing. However, to date, studies in normal human volunteers have proved inconsistent. We have therefore tested the effects of the dopamine D2 receptor antagonist sulpiride (400 mg) on WM and learning tasks, including those using auditory, spatial or non-spatial stimuli. A further aim was to explore a broader role of the dopaminergic system in mnemonic function by examining long-term and emotional memory. Eighteen healthy male participants were given a battery of cognitive tests after oral sulpiride or placebo, using the cross-over design. WM was assessed using a spatial searching task, and a task of auditory counting with distraction. Tasks that did not emphasize WM were spatial and non-spatial trial-and-error learning, long-term spatial memory and emotional memory. After dopamine D2 receptor blockade, performance was not impaired on the spatial WM (SWM) task, but was impaired on the auditory counting task with distraction. Sulpiride did not impair, but rather appeared to enhance trial-and-error learning overall. Thus, we were unable to support the notion that dopaminergic modulation preferentially influences spatial over non-spatial processing during learning. In addition, recognition was impaired in the emotional memory task after encoding on drug compared to placebo. These findings question the precise role of dopamine D2 receptor modulation on WM, and highlight the need for sensitive tests to study dopaminergic modulation of emotional processing.

Adult↗
PubMed1998

Memory states and memory tasks: an integrative framework for eyewitness memory and suggestibility.

An integrative framework (IMP) is presented which depicts performance in eyewitness suggestibility experiments as the participants' solutions of memory tasks, depending on (a) a specified task-relevant memory base and (b) the participants' perception of the memory task. Three theoretical explanations of the effect of misleading post-event information are reinterpreted and reduced to one single core: individuals answer test questions while assuming the consistency of event and post-event information. The impact of such consistency assumptions (a) is demonstrated in a first experiment, where the usual misinformation effect obtained with the Loftus standard test procedure disappeared when the participants' consistency assumptions were destroyed prior to testing, and (b) manifests itself in a qualitative analysis of individual processing strategies for discrepancies between details. Experiment 2, employing methodological innovations suggested by IMP, examined the memory base and found no evidence for memory impairment or misattributions of post-event details to the witnessed scene. However, a follow-up study conducted four and a half months later revealed a strong tendency for such misattributions which might indicate long-term integration of information.

Adolescent↗
PubMed2000

The effects of word co-occurrence on short-term memory: associative links in long-term memory affect short-term memory performance.

In immediate serial recall tasks, high-frequency words are recalled better than low-frequency words. This has been attributed to high-frequency words' being better represented and providing more effective support to a redintegration process at retrieval (C. Hulme et al., 1997). In studies of free recall, there is evidence that frequency of word co-occurrence, rather than word frequency per se, may explain the recall advantage enjoyed by high-frequency words (J. Deese, 1960). The authors present evidence that preexposing pairs of low-frequency words, so as to create associative links between them, has substantial beneficial effects on immediate serial recall performance. These benefits, which are not attributable to simple familiarization with the words per se, do not occur for high-frequency words. These findings indicate that associative links between items in long-term memory have important effects on short-term memory performance and suggest that the effects of word frequency in short-term memory tasks are related to differences in interitem associations in long-term memory.

Adult↗
PubMed1985

Differential effects of electroconvulsive shock on concurrent spatial memories: "old" memories are impaired while "new" memories are spared.

The effects of electroconvulsive shock (ECS) on spatial memory first reported by Shavalia, Dodge, and Beatty (1981, Behavioral and Neural Biology, 31, 261-273) were systematically replicated in two experiments. Rats acquired concurrent spatial memories in two 8-arm radial mazes. Each rat was allowed four choices in Maze 1 and then, after 2 h, four choices in Maze 2. After 2 h each rat was tested for retention in Maze 1 and, after 2 more h, was tested for retention in Maze 2. A single ECS was administered immediately after the fourth choice in Maze 2. Retention (as measured by accuracy of Choices 5-8) was diminished for Maze 1 but not for Maze 2. In the second experiment, the delay between the retention tests was eliminated (thus holding the ECS-Choice 5 interval constant for the two mazes). Once again retention of Maze 1 was impaired and retention of Maze 2 was spared; that finding suggests that ECS does not proactively affect radial-arm maze performance. The results of a third experiment converge on the same conclusion; ECS failed to reduce levels of spontaneous alternation. Therefore, ECS appears to interfere retroactively with relatively old spatial memories and newly established memories appear to be immune to the amnestic effects of ECS. Implications and various explanations are considered.

Animals↗
PubMed1972

Immunological memory in mice. 3. Memory to heterologous erythrocytes in both T cell and B cell populations and requirement for T cells in expression of B cell memory. Evidence using immunoglobulin allotype and mouse alloantigen theta markers with congenic mice.

Using anti-allotype sera and AKR anti thetaC3H sera, a requirement for two cell types has been demonstrated in the adoptive secondary response of mice to heterologous erythrocytes. The cell types have been designated B cells [precursors of plaque-forming cells (PFC)] and T cells (thymus-influenced cells, not providing precursors of detectable PFC). The in vivo indirect PFC response of spleen cells from primed mice is markedly reduced by in vitro treatment of the cells with a mixture of anti-theta serum and guinea pig serum (Anti theta + GPS). This B cell response is fully restored to control levels by thymus cells from normal mice which do not themselves provide precursors of indirect PFC. Thus memory is carried by the B cell lineage but the expression of this memory is dependent on the presence of a cell population which is sensitive to Anti theta + GPS and which is replaced functionally by unprimed T cells. When assayed for T cell activity, thoracic duct cells from specifically primed mice are better than cells from nonspecifically primed mice in restoring the B cell response of spleen cells from immunized mice. Moreover, the T cell activity of a reconstitutive cell population from primed mice is reduced by incubation with Anti theta + GPS. We conclude that memory to heterologous erythrocyte antigens is carried by the T cell lineage as well as the B cell lineage even though unprimed T cells are sufficient for expression of B cell memory.

Animals↗
PubMed1990

Memory restoration or memory block: differential effects of physostigmine depend on the age of the memory trace.

The authors investigated the effect of physostigmine (Ph) on short-term memory underlying the response-to-change test in rats. In the first test trial (acquisition) the rat could observe the white-black T-maze arms through transparent partitions which prevented the entrance to the arms. In the subsequent trial the rat was allowed a free choice between two identical maze arms, one of them being changed from white to black or vice versa. Physostigmine or saline (NaCl) was injected i.p. 1 min after the acquisition trial. When the retention interval between the two trials was short (10 min), NaCl rats showed a significant preponderance of the changed arm choices, whereas after a longer retention interval (20 min) they selected the changed arm in low percentage. This indicated a rapid decline of memory traces underlying the response to the change of brightness. Physostigmine in a dose of 0.1 mg/kg blocked responding to change after 10 min retention interval, when the memory was strong. However, when tested after a 20 min interval, Ph injected rats showed restoration of memory. After a 15 min interval, retention in both NaCl and Ph injected rats was on a similar, intermediate level. A higher dose of Ph (0.3 mg/kg) had no effect on responding to change after any retention interval examined in this experiment.

Amnesia↗
PubMed2005

A new approach to the pharmacological regulation of memory: Sarsasapogenin improves memory by elevating the low muscarinic acetylcholine receptor density in brains of memory-deficit rat models.

The purpose of this paper is to study the basic pharmacological action of sarsasapogenin, a sapogenin from the Chinese medicinal herb Rhizoma Anemarrhenae, (abbreviated as ZMS in this paper), on learning ability and memory of three animal models: aged rats and two neurodegeneration models produced either by single unilateral injection of beta-amyloid 1-40 (Abeta1-40) plus ibotenic acid (Ibot A) or by bilateral injection of Ibot A alone into nucleus basalis magnocellularis. Y-maze test and step-through test revealed that learning ability and memory were impaired in the three models and were improved by oral administration of ZMS. ZMS did not inhibit acetylcholinesterase nor did it occupy the binding sites of muscarinic acetylcholine receptor (M receptor), hence it is neither an cholinesterase inhibitor nor an agonist or antagonist of M receptors. On the other hand, the densities of total M receptor and its M1 subtype in the brain of the three models were significantly lower than control rats, and ZMS significantly raised the densities of total M receptors and its M1 subtype. Linear regression revealed significant correlation between the learning ability/memory and the density of either total M receptor or its M1 subtype. Autoradiographic study with 3H-pirenzipine showed that the M1 subtype density was significantly lowered in cortex, hippocampus and striatum of aged rats, and ZMS could reverse these changes towards normal control level. Interestingly, the M1 receptor density after ZMS administration only approached but did not exceed that of normal young control rats. Therefore, ZMS seems to represent a new approach to the pharmacological regulation of learning and memory and appears to be not simply palliative but may modify the progression of the disease.

Acetylcholinesterase↗