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PubMed1999

Support for a theory of memory for event duration must distinguish between test-trial ambiguity and actual memory loss.

Staddon and Higa's (1999) trace-strength theory of timing and memory for event duration can account for pigeons' bias to "choose short" when retention intervals are introduced and to "choose long" when, following training with a fixed retention interval, retention intervals are shortened. However, it does not account for the failure of pigeons to choose short when the intertrial interval is distinct from the retention interval. That finding suggests that stimulus generalization (or ambiguity) between the intertrial interval and the retention interval may result in an effect that has been attributed to memory loss. Such artifacts must be eliminated before a theory of memory for event duration can be adequately tested.

Animals↗
PubMed2006

Primary and secondary memory: multistore versus process models of memory.

Healy, et al. recently distinguished between recency and "penultimate" effects when contrasting recall performance. They argued that the penultimate effect was significantly different from the typical recency effect, which point was taken as support for distinguishing between primary and secondary memory systems. The current study adapted the Healy, et al. methodology to control for the occurrence of intentional learning strategies. 40 participants were asked to recall the names of 42 U.S. Presidents by their term in office (secondary memory) or in a pseudorandom order (primary memory); the recency and penultimate effects were observed for each condition. With intentional learning controlled for, contrast analyses yielded a pattern of performance similar to that observed by Healy, et al.

Adolescent↗
PubMedDate not supplied

Implementation of a compensatory memory system in a school age child with severe memory impairment.

Impairments in memory and new learning secondary to neurological illness or injury pose significant problems for school age children. This paper describes the development and implementation of compensatory memory aids for an adolescent girl who demonstrated significant memory impairment following irradiation for an intracranial tumour. Strategies for integrating the system with the student's academic programme and school-related activities, and involvement of school personnel are emphasized, as is a theoretically and behaviourally based training programme.

Adolescent↗
PubMed2006

Availability of related long-term memory during and after attention focus in working memory.

In a series of four experiments, we investigated the magnitude and pattern of indirect, semantically mediated priming that emanates from various working memory (WM) processes. When such priming effects are taken to reflect temporary increases in the availability of long-term memory (ALTM), results suggest a close link between the amount and type of attention-driven processing in WM and the resulting accessibility of semantically related memory structures. Patterns of priming were equivalent when attention demands were prior to, versus concurrent with, the priming measures, suggesting that ALTM processes either require no additional cognitive resources or require resources that are independent of those underlying effortful WM processes. The results are discussed with respect to emerging evidence for long-term semantic priming and models of WM that incorporate active but unattended information as part of a limited capacity cognitive workspace.

Adult↗
PubMed2004

Relations between emotion, memory, and attention: evidence from taboo stroop, lexical decision, and immediate memory tasks.

This article reports five experiments demonstrating theoretically coherent effects of emotion on memory and attention. Experiments 1-3 demonstrated three taboo Stroop effects that occur when people name the color of taboo words. One effect is longer color-naming times for taboo than for neutral words, an effect that diminishes with word repetition. The second effect is superior recall of taboo words in surprise memory tests following color naming. The third effect is better recognition memory for colors consistently associated with taboo words rather than with neutral words. None of these effects was due to retrieval factors, attentional disengagement processes, response inhibition, or strategic attention shifts. Experiments 4 and 5 demonstrated that taboo words impair immediate recall of the preceding and succeeding words in rapidly presented lists but do not impair lexical decision times. We argue that taboo words trigger specific emotional reactions that facilitate the binding of taboo word meaning to salient contextual aspects, such as occurrence in a task and font color in taboo Stroop tasks.

Adult↗
PubMed2004

HIV-1-specific memory CD4+ T cells are phenotypically less mature than cytomegalovirus-specific memory CD4+ T cells.

HIV-1-specific CD4(+) T cells are qualitatively dysfunctional in the majority of HIV-1-infected individuals and are thus unable to effectively control viral replication. The current study extensively details the maturational phenotype of memory CD4(+) T cells directed against HIV-1 and CMV. We find that HIV-1-specific CD4(+) T cells are skewed to an early central memory phenotype, whereas CMV-specific CD4(+) T cells generally display a late effector memory phenotype. These differences hold true for both IFN-gamma- and IL-2-producing virus-specific CD4(+) T cells, are present during all disease stages, and persist even after highly active antiretroviral therapy (HAART). In addition, after HAART, HIV-1-specific CD4(+) T cells are enriched for CD27(+)CD28(-)-expressing cells, a rare phenotype, reflecting an early intermediate stage of differentiation. We found no correlation between differentiation phenotype of HIV-1-specific CD4(+) T cells and HIV-1 plasma viral load or HIV-1 disease progression. Surprisingly, HIV-1 viral load affected the maturational phenotype of CMV-specific CD4(+) T cells toward an earlier, less-differentiated state. In summary, our data indicate that the maturational state of HIV-1-specific CD4(+) T cells cannot be a sole explanation for loss of containment of HIV-1. However, HIV-1 replication can affect the phenotype of CD4(+) T cells of other specificities, which might adversely affect their ability to control those pathogens. The role for HIV-1-specific CD4(+) T cells expressing CD27(+)CD28(-) after HAART remains to be determined.

Antiretroviral Therapy, Highly Active↗
PubMed2002

[Effects of imagery instructions on false memories produced on implicit and explicit memory tests].

In two experiments, we investigated whether the Deese-Roediger-McDermott paradigm using implicit and explicit memory tests would produce critical lure (CL) words. Participants studied lists of semantic associates (e.g., newspaper, book, write) to induce memories for CL words (e.g., read). Afterwards, participants participated in implicit and explicit memory tests in each experiment. The level of priming of the CL words was quite high and similar to that of the presented words when participants were instructed to image the interword relation on lists during study. Participants explicitly recognized many CL words as having been presented on the lists in Experiment 1 and recalled many CL words in Experiment 2. The results are discussed in light of Underwood's (1965) implicit associative response hypothesis.

Adult↗
PubMedDate not supplied

Contrasting cortical activity associated with category memory and recognition memory.

We collected functional neuroimaging data while volunteers performed similar categorization and recognition memory tasks. In the categorization task, volunteers first studied a series of 40 dot patterns that were distortions of a nonstudied prototype dot pattern. After a delay, while fMRI data were collected, they categorized 72 novel dot patterns according to whether or not they belonged to the previously studied category. In the recognition task, volunteers first studied five dot patterns eight times each. After a delay, while fMRI data were collected, they judged whether each of 72 dot patterns had been studied earlier. We found strikingly different patterns of brain activity in visual processing areas for the two tasks. During the categorization task, the familiar stimuli were associated with decreased activity in posterior occipital cortex, whereas during the recognition task, the familiar stimuli were associated with increased activity in this area. The findings indicate that these two types of memory have contrasting effects on early visual processing and reinforce the view that declarative and nondeclarative memory operate independently.

Adult↗
PubMed2000

[Improving memory effects of eel oil capsule on memory obstruction of mice hurt by anisodine].

The effects of eel oil capsule on memory obstruction of mice were observed in step-down test, step-through test, Y-maze test and Japanese labyrinth test. The results indicated that the eel oil capsule treating group with dosages of 0.234, 0.702 and 2.106 g/kg markedly enhance the acquirement, strengthing and reappearance of memory, having the functions of improving brain memory hurt by Anisodine.

Animals↗
PubMed2005

Treatment with magnesium improves reference memory but not working memory while reducing GFAP expression following traumatic brain injury.

PURPOSE: Previous studies have shown that administration of MgCl2 in animal models of brain injury significantly improves functional recovery: however, few studies have examined cognitive recovery. The present study evaluated the effect of MgCl2 pharmacotherapy on recovery of function following medial frontal cortex contusion injury. METHODS: Groups of rats were assigned to either MgCl2 (1.0 mmol/kg) or saline treatment conditions and prepared with contusion injuries or shams. Drug treatment was administered 15 min and 24 hr following injury. Rats were examined on tests of sensorimotor performance (bilateral tactile adhesive removal) and cognitive ability (reference and working memory). RESULTS: Administration of MgCl2 following injury significantly reduced the behavioral impairments observed on the bilateral tactile removal test. The acquisition of reference memory was also significantly improved compared to saline-treated rats; however, treatment did not improve working memory performance. Lesion analysis revealed that administration of MgCl2 did not significantly reduce lesion size compared to saline-treatment. Examination of glial fibrillary acidic protein (GFAP) expression showed that MgCl2 did significantly reduce the number of GFAP+ cells. CONCLUSION: These results indicate that MgCl2 administration significantly improved behavioral outcome following injury in a task dependent manner and reduced GFAP expression.

Animals↗
PubMed2005

A single case experimental design comparing two memory notebook formats for a man with memory problems caused by traumatic brain injury.

There is extensive literature demonstrating that restoration of memory is not a realistic goal for rehabilitation and that efforts are more effective if focused on developing compensatory strategies. This paper compares two formats of memory notebook using an ABAB single-case experimental design with a 46-year-old man with a history of head injury. Results revealed significantly better performance on a series of prospective memory tasks for the "modified" notebook. The study highlights the importance of tailoring the diary to the patient's needs and giving careful consideration to the way in which the diary is introduced.

Brain Injuries↗
PubMed1977

The generation of memory cells. I. The role of C3 in the generation of B memory cells.

Adult thymectomized, repopulated mice were chronically depleted of circulating C3 by treatment with cobra venom factor after primary immunization with dinitrophenylated haemocyanin (DNP-KLH). This treatment totally abrogated the development of B-cell memory in such mice, as assayed by a co-operative lymphocyte transfer. The failure of memory development appeared to involve impaired precursor proliferation following priming. It was further shown that the localization of DNP-KLH in splenic lymphoid follicles is both antibody and C3-dependent; thymus-deprived mice make sufficient antibody to DNP-KLH to effect follicular localization of the antigen. On the basis of these and earlier observations we suggest that the development of B-memory cells involves the formation of antigen-antibody-C3 complexes on dendritic cells in lymphoid follicles. C3 may serve to stabilize the antigen bridge between dendritic cells and virgin precursors. In complete contrast, C3 depletion had little effect on the functional expression of primed B cells, thus suggesting that only the early stages of B-cell triggering are C3 dependent.

Animals↗
PubMed1978

The generation of memory cells. II. Generation of B memory cells with preformed antigen-antibody complexes.

Mice were immunized with preformed complexes of dinitrophenylated haemocyanin (DNP-KLH) and anti-DNP or anti-KLH antibodies, and subsequently assayed for the generation of B memory (BM) cells. Complexes formed at equivalence or in slight antigen excess were far more effective than antigen alone in generating memory: as little as 100 ng DNP-KLH-anti-DNP produced substantial B cell priming. Anti-carrier and anti-hapten antibodies were equally effective. Complexes generated memory more rapidly than antigen alone, and the adjuvant effect was not simply due to aggregation of the antigen. Optimal priming by complexes required the integrity of the Fc portion of the antibody: F(ab')2 antibody fragments were less effective. The capacity of complexes to prime BM cells was abrogated by depriving mice of C3. C3 was also required for localization of complexes within splenic lymphoid follicles; complexes made with F(ab')2 localized in follicles, but less efficiently than those made with intact antibody. These results extend earlier findings (Klaus & Humphrey, 1977) and strongly suggest that the generation of BM cells involves the C3-dependent localization of antigen-antibody complexes within lymphoid follicles and strengthen the concept that germinal centres are the birthplace of BM cells.

Animals↗
PubMed1979

Generation of memory cells. III. Antibody class requirements for the generation of B-memory cells by antigen--antibody complexes.

Immunizing mice with preformed antigen--antibody complexes is a highly effective means of generating B-memory cells. In the present study we have compared the capacity of mouse anti-dinitrophenyl (DNP) IgM, IgG1, IgG2 and IgA antibodies to generate DNP-specific memory, when given in complex with antigen (DNP-KLH: keyhole limpet haemocyanin). Two monoclonal IgM antibodies exerted no adjuvant effect, whereas a monoclonal IgA antibody was effective, IgG2 antibodies were a more powerful adjuvant than IgG1, regardless of whether anti-DNP or anti-KLH antibodies were used. Furthermore, the capacity of DNP-KLH--antibody complexes to localize in splenic lymphoid follicles could be ranked IgG2 greater than IgG1 greater than IgA; IgM complexes did not localize in follicles. These results correlate well with data (presented elsewhere) on the capacity of these different antibodies to activate mouse complement, and confirm that C activation is an essential requirement for both follicular localization of immune complexes, and for the generation of B-memory cells. Although activation of the alternative complement pathway is sufficient to effect both processes, the results with IgG2 antibodies raise the possibility that classical pathway activation may be more effective.

Animals↗
PubMed1986

Memory evaluation of alcoholics with Russell's revised Wechsler Memory Scale.

Fifty-four alcoholics and 30 nonalcoholics were tested on Russell's (1975) revision of the Wechsler Memory Scale (RWMS). Subjects were dichotomized into groups of old and young, and alcoholics were divided further into groups of short- and long-term abusers. Groups were matched on socioeconomic status. Significant group differences were found on three of the four RWMS measures as a function of abuse status and on two of the measures as a function of age. In terms of severity of impairment, alcoholics were found to demonstrate only mild verbal and figural memory deficits when compared to age-matched controls. Results are discussed with regard to the clinical utility of the RWMS as a memory screening instrument with alcoholic patients and in terms of treatment implications.

Adult↗
PubMed2002

Age, memory load, and individual differences in working memory as determinants of class-inclusion reasoning.

We studied the effects of individual differences in speak-span scores and variations in memory demands on the class-inclusion performance of 10-, 13-, and 15-year-old children. The speak-span task was an age-appropriate modification of Daneman and Carpenter's (1980) reading-span task and was considered to be a measure of global resources. The age variable was assumed to be a global index of skill development, and some of the specific skills hypothesized to be important in class-inclusion reasoning were estimated using a mathematical model. The results from both regression analyses and the mathematical model indicated that differences in age, speak span, and memory load all affected performance. Surprisingly, the effects of speak span and memory load were independent. However, the effects of each of these variables depended on the age level of the participants. Based on these findings, we argued that (a) resources vary continuously with age, (b) both skill level and global resources should be varied in developmental studies of problem solving, and (c) resource theories (e.g., Norman & Shallice, 1986) should be modified to account for developmental change.

Adolescent↗
PubMed1999

The role of the prefrontal cortex in recognition memory and memory for source: an fMRI study.

We employed fMRI to index neural activity in prefrontal cortex during tests of recognition and source memory. At study, subjects were presented with words displayed either to the left or right of fixation, and, depending on the side, performed one of two orienting tasks. The test phase consisted of a sequence of three 10-word blocks, displayed in central vision. For one block, subjects performed recognition judgements on a mixture of two old and eight new words (low density recognition). For another block, recognition judgements were performed on a mixture of eight old and two new words (high density recognition). In the remaining block, also consisting of eight old and two new items, the requirement was to judge whether each word had been presented at study on the left or the right. Relative to the low density condition, high density recognition was associated with increased activity in right and, to a lesser extent, left, anterior prefrontal cortex (BA 10), replicating the findings of two previous PET studies. Right anterior prefrontal activity did not show any further increase during the source task. Instead, greater activity was found, relative to high density recognition, in left BA 10, left inferior frontal gyrus (BA 45/47), and bilateral opercular cortices (BA 45/47). The findings are inconsistent with the proposal that activation of right anterior prefrontal cortex during memory retrieval reflects "postretrieval" processing demands, such demands being considerably greater for judgments of source than recognition. The findings provide further evidence that the left prefrontal cortex plays a role in episodic memory retrieval when the task explicitly requires recovery of contextual as well as item information.

Adult↗