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PubMed1994

The Extended Rivermead Behavioural Memory Test: a measure of everyday memory performance in normal adults.

The Rivermead Behavioural Memory Test provides a well-validated instrument for detecting everyday memory problems in patient groups. It was however designed as a screening test, and thus is insufficiently sensitive to detect mild deficits, whether due to brain damage or to the introduction of a drug or stressor. The Extended Rivermead Behavioural Memory Test (ERBMT) increases the level of difficulty by doubling the amount of material to be remembered, by combining material from Forms A and B, and Forms C and D of the original test to produce two parallel versions of the new extended test. The sensitivity of the ERBMT was assessed by comparing the performance of a middle-aged and an elderly group of normal subjects, who would be expected to show modest differences in memory performance. The subtests varied in their sensitivity to this small age difference, but when performance was assessed in terms of scaled scores that allow an overall combined measure of memory performance to be calculated, the test proved sensitive (t = 4.87, P < 0.0001), and free of ceiling and floor effects. We suggest that the ERBMT provides a promising measure of everyday memory in normal adults.

Adult↗

PubMed2005

Visual memory testing in older adults with age-related visual decline: a measure of memory performance or visual functioning?

Although we know that vision is correlated with memory performance in older adults, the implications for this in terms of neuropsychological assessment have not been investigated. Relationships among age, visual acuity, and visual and verbal memory in 89 community dwelling volunteers aged 60 to 87 years were examined. Vision was tested using the Landolt C and visual and verbal memory were assessed via the Visual Reproduction (VR) and Word List (WL) subtests from the Wechsler Memory Scale, Third Edition (WMS-III; Wechsler, 1997), respectively. Significant correlations were observed between vision and the VR and WL tasks. Hierarchical multiple regression analyses revealed that vision significantly increased the R2 for VR and WL after controlling for age and education. The effect of vision was not specific to visual memory. We conclude that vision is correlated with general memory function in older adults, and is not modality specific.

Aged↗

PubMed1985

Working-memory capacity, age, and memory for discourse.

Two experiments explored the issue of whether age-related differences in memory for discourse can be explained by age-related differences in working memory capacity. Young and older adults were given a series of tasks designed to measure working memory capacity and memory for paragraphs. Although age-related differences were observed on digit, word, and sentence spans as well as on recall (Experiment 1) and recognition (Experiment 2), retention was not predicted well by scores on any of the span measures for either young or older adults in either experiment. The implications of these findings for hypotheses that age-related declines in working memory are responsible for problems in memory for prose are considered.

Adult↗

PubMed2006

Type I cytokine profiles of human naïve and memory B lymphocytes: a potential for memory cells to impact polarization.

B cells bifurcating along 'type 1' or 'type 2' pathways under the influence of polarizing cytokines can, in turn, influence the direction of an immune response. Here, we compare the capacity of human B cells residing within naïve and memory compartments to participate in type 1 polarizing responses. B-cell receptor (BCR) engagement provided the main signal for interleukin (IL)-12Rbeta1 expression in the two subsets: this was potentiated by CD154 together with interferon-gamma (IFN-gamma) but inhibited by IL-12. IL-12Rbeta2 could be induced on a minority of B cells by the same signals, and also by IFN-gamma alone. WSX-1, a receptor for IL-27, was expressed in both subsets with no evidence for its regulation by the signals studied. While neither subset was capable of secreting much IL-12 p70, memory B cells could produce a small amount of IL-12 p40 on CD40 ligation. Memory B cells also, exclusively, expressed IL-23 p19 mRNA on BCR triggering. Importantly, products of appropriately stimulated memory--but not naive--B cells were shown to promote the synthesis of IFN-gamma in uncommitted T-helper cells. The data indicate an equal capacity for naïve and memory B cells to respond within a type 1 polarizing environment. Although poorly equipped for initiating type 1 responses, B cells--by virtue of the memory subset--reveal a capacity for their maintenance and amplification following T-dependent signalling.

B-Lymphocyte Subsets↗

PubMed2004

Episodic memory impairment in bipolar disorder and obsessive-compulsive disorder: the role of memory strategies.

BACKGROUND: There is evidence that individuals with bipolar disorder exhibit neuropsychological impairments not only during mood episodes but also when they are euthymic. One of the most consistently reported cognitive problems in euthymic individuals with bipolar disorder is an impairment in verbal episodic memory. Verbal learning and memory depend on individuals' ability to organize verbal information appropriately during learning. The purpose of the present study was (i) to determine whether episodic memory impairment in euthymic individuals with bipolar disorder is mediated by impairments in organization of verbal information during learning and (ii) to compare the characteristics of memory impairment in bipolar disorder with that previously found in obsessive-compulsive disorder (OCD). METHODS: Study participants were 30 individuals with DSM-IV bipolar I disorder (BP-I), 30 individuals with DSM-IV OCD and 30 normal control participants matched for age, gender and education. Participants completed the California Verbal Learning Test (CVLT), a well-established measure of verbal learning and memory that enables assessment of verbal organization strategies during learning. RESULTS: Compared with control subjects, both BP-I and OCD participants showed impaired performance in long-delayed free recall and verbal organization strategies during learning. BP-I participants showed greater long-delay free recall difficulties but not greater verbal organization difficulties during learning than OCD participants. For OCD participants, the long-delay recall impairment was mediated by difficulties using verbal organizational strategies during learning. In contrast, the group difference in long-delayed free recall between BP-I and control participants remained significant even when semantic clustering was introduced as a mediator. This indicated that BP-I participants' long-delayed free recall difficulties were mediated to a lesser extent by difficulties using verbal organizational strategies than for OCD participants. CONCLUSIONS: Verbal episodic memory problems in individuals with bipolar I disorder and OCD are mediated to different degrees by difficulties using semantic clustering encoding strategies compared with control participants.

Adult↗

PubMed2006

Attenuating corticosterone levels on the day of memory assessment prevents chronic stress-induced impairments in spatial memory.

This study investigated whether chronic stress-induced spatial memory deficits were caused by changes in the hypothalamic-pituitary-adrenal axis, such as corticosterone (CORT) elevations on the day of memory assessment, rather than the consequence of structural changes in the hippocampus. Male Sprague-Dawley rats were restrained for 6 h/day/21 days, and spatial memory was assessed on the Y-maze on day 22. Ninety minutes before training, rats received a subcutaneous injection of vehicle or metyrapone, a CORT synthesis inhibitor, and then spatial memory was determined 4-h later. The highest dose of metyrapone (75 mg/kg, s.c.) was most effective at preventing stress-induced spatial memory deficits. Chronic stress increased total CORT levels following Y-maze exposure, while acute metyrapone treatment dose-dependently attenuated total and free (unbound) CORT levels in both stress and control conditions. Blood samples taken from a separate subset of chronically stressed rats showed that baseline CORT levels were similar across the restraint period. Finally, chronic stress down-regulated glucocorticoid, but not mineralocorticoid, receptor mRNA expression within the hippocampus (dentate gyrus, CA1, CA2, CA3). These findings suggest that chronic stress-induced spatial memory deficits may be mediated by hypothalamic-pituitary-adrenal axis dysregulation. Specifically, CORT elevations and reductions in hippocampal glucocorticoid receptor expression, at the time of behavioural assessment may be involved, as opposed to a direct effect that is solely dependent upon hippocampal structural changes. These results have significance for treating cognitive decline in conditions associated with elevated glucocorticoids that include subpopulations in ageing, depression, Cushing's disease and Alzheimer's disease.

Aging↗

PubMed1999

Effects of incorporating memory confidence ratings and language handicap modifications on intracarotid amobarbital procedure (Wada test) memory asymmetry scores.

PURPOSE: Intracarotid amobarbital procedure (IAP) memory asymmetry scores are often considered in determining lateralization of temporal lobe seizure foci. Additionally, these scores sometimes influence treatment plans for epilepsy surgery candidates. We examined the effects of two scoring modifications on IAP asymmetry scores: incorporating memory confidence ratings (MC), and use of a language handicap (LH) (i.e., adding a point to the memory score with anesthetization of the language-dominant hemisphere), both of which could be applied to most IAP protocols despite variations in testing methods among epilepsy surgery programs. METHODS: Sixty-nine consecutive unilateral temporal lobe epilepsy (TLE) patients with subsequent good surgical outcomes (Engel I or II) underwent bilateral IAP testing. Confidence ratings were obtained for all memory responses. The incorporation of confidence ratings and the application of a language handicap for dominant-hemisphere injections were applied to memory asymmetry scores in all combinations, resulting in four scoring methods. Results of the four methods were compared with respect to the proportion of patients lateralized accurately by each method. RESULTS: No patients were falsely lateralized with any method. Percentage of patients correctly lateralized with each scoring method is shown in Table 2. The results obtained with MC and with MC + LH (67% and 64% of patients accurately lateralized, respectively) were significantly better than results obtained with LH (55%, p<0.05). No other differences were significant. CONCLUSIONS: Although not statistically superior to standard methods, these results suggest that incorporating memory confidence ratings into IAP protocols may increase the likelihood of obtaining asymmetry scores that accurately lateralize to the hemisphere of seizure onset. In contrast, inclusion of a language handicap for scores obtained with the language-dominant ICA injection were not helpful and may even decrease the probability of obtaining clinically useful lateralizing data. These scoring modifications can be applied to most IAP protocols.

Adult↗

PubMed1996

Lipopolysaccharide induces apoptotic cell death of B memory cells and regulates B cell memory in antigen-nonspecific manner.

Lipopolysaccharide (LPS) was administered into sheep red blood cells (SRBC)-primed mice, and the effect of LPS on SRBC-specific memory cells was investigated. Spleen cells from SRBC-primed mice which were injected with LPS exhibited much lower in vitro secondary plaque-forming cells (PFC) responses to SRBC than those from untreated SRBC-primed mice. The in vitro anti-SRBC response of the spleen cells to LPS was also reduced. The combination experiments of B cells and T cells from SRBC-primed mice which were injected with or without LPS demonstrated that the reduction of immune responses to SRBC after administration of LPS was caused by the defect of SRBC-specific B memory cells, but not T memory cells. B cell type rosette-forming cells (RFC) for SRBC markedly decreased after injection of LPS, while PFC as antibody-forming cells did not increase subsequently. Therefore, the reduction of RFC was not due to their differentiation into PFC. The lymphoid follicles in the spleens from mice injected with LPS were stained positively by in situ nick end labeling specific for fragmented DNA. A large percentage of Ig+ spleen cells from SRBC-primed mice which were injected with LPS was also stained positively. The injection of glucocorticoids into SRBC-primed mice induced similar reduction of B memory cells. It was suggested that LPS might induce apoptosis of B memory cells and regulate B cell memory in antigen-nonspecific manner.

Animals↗

PubMed1992

Role of inferior temporal neurons in visual memory. II. Multiplying temporal waveforms related to vision and memory.

1. In the companion paper we reported on the activity of neurons in the inferior temporal (IT) cortex during a sequential pattern matching task. In this task a sample stimulus was followed by a test stimulus that was either a match or a nonmatch. Many of the neurons encoded information about the patterns of both current and previous stimuli in the temporal modulation of their responses. 2. A simple information processing model of visual memory can be formed with just four steps: 1) encode the current stimulus; 2) recall the code of a remembered stimulus; 3) compare the two codes; 4) and decide whether they are similar or different. The analysis presented in the first paper suggested that some IT neurons were performing the comparison step of visual memory. 3. We propose that IT neurons participate in the comparison of temporal waveforms related to vision and memory by multiplying them together. This product could form the basis of a crosscorrelation-based comparison. 4. We tested our hypothesis by fitting a simple multiplicative model to data from IT neurons. The model generated waveforms in separate memory and visual channels. The waveforms arising from the two channels were then multiplied on a point by point basis to yield the output waveform. The model was fitted to the actual neuronal data by a gradient descent method to find the best fit waveforms that also had the lowest total energy. 5. The multiplicative model fit the neuronal responses quite well. The multiplicative model made consistently better predictions of the actual response waveforms than did an additive model. Furthermore, the fit was better when the actual relationship between the responses and the sample and test stimuli were preserved than when that relationship was randomized. 6. We infer from the superior fit of the multiplicative model that IT neurons are multiplying temporally modulated waveforms arising from separate visual and memory systems in the comparison step of visual memory.

Animals↗

PubMedDate not supplied

Relationship of self-perceptions of memory and worry to objective measures of memory and cognition in the general population.

This investigation compared how perceived memory ability or level of worry about memory related to performance on objective tests of memory and cognition. Data from 1,488 participants from the Baltimore cohort of the Epidemiologic Catchment Area study were analyzed. Significant associations were found between self-ratings of memory and each of four objective measures of cognitive functioning. Memory worry was associated with worse delayed recall but not with worse word recognition, lower current Mini-Mental State Examination (MMSE) score, or greater change in MMSE score over time. Individuals experiencing changes in cognitive function appear to have some awareness of their condition, and a simple probe of a person's perception of memory in the context of a general medical evaluation may help identify those who need further assessment.

Adult↗

PubMed1996

A critical review of recovered memories in psychotherapy: Part I--Trauma and memory.

OBJECTIVE: The theoretical basis of the use of recovered memories in psychotherapy will be critically examined. METHOD: Literature will be reviewed on the nature of normal memory, and on the relationship of trauma to memory. RESULTS: Normal memories are surprisingly inaccurate. There is little evidence that normal memories can be repressed. There is no evidence that trauma makes repression more likely. CONCLUSIONS: "Recovery" of repressed memories is not consistent with the findings of empirical research.

Humans↗

PubMed2005

Central memory and effector memory subsets of human CD4(+) and CD8(+) T cells display differential sensitivity to TNF-{alpha}-induced apoptosis.

Upon activation by antigen, naive T cell subsets undergo proliferation and differentiation into effector cells, followed by the generation of a pool of memory T cells. Based upon migration pattern and functions, they are classified into central memory (predominantly homing to the lymph nodes) and effector memory (predominantly homing to extralymphoid sites) subsets. These subsets are defined phenotypically by a set of cell surface molecules. In this investigation, we demonstrate that naive and central memory CD4(+) and CD8(+) T cells in humans undergo tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis, whereas effector memory CD4(+) and CD8(+) T cells are relatively resistant to TNF-alpha-induced apoptosis. We also provide evidence for the molecular mechanisms underlying the differential sensitivity of naive and different sets of memory T cells to TNF-alpha-induced apoptosis.

Adolescent↗

PubMed1999

Relative interference on Logical Memory I Story A versus Story B of the Wechsler Memory Scale-revised in a clinical sample.

Prior research found Logical Memory I Story A and Story B of the Wechsler Memory Scale-Revised to be equivalent in difficulty, with no effect of administration sequence. Following clinical impression of many patients "freezing" on Story A and recovering on Story B, it was hypothesized that the presence of performance or test anxiety contributed to this phenomenon. Logical Memory scores and concurrent Minnesota Multiphasic Personality Inventory (MMPI) data from 85 clinical cases were examined. Participants were divided into 3 groups based on performance on the Logical Memory I stories: A < B (67%), A = B (15%), A > B (18%). There were no significant differences on Logical Memory I performance related to medical or neuropsychiatric history, age, or education. In support of the hypothesis, those patients who showed poorer performance on Logical Memory I Story A than on Story B had significantly higher T scores on the MMPI Social Anxiety scale as compared to the A > B group. No other MMPI differences were found.

Adult↗

PubMed2002

Gone but not forgotten: the lingering effects of intermediate-term memory on the persistence of long-term memory.

Aerial respiratory behaviour can be operantly conditioned in Lymnaea stagnalis and, depending on the interval between the training sessions, memories of significantly different durations are produced. In naïve snails, a 15 min training procedure with a 30 min interval between three training sessions results in memory that persists for only 3 h (intermediate-term memory, ITM); whilst if the three 15 min training sessions are separated by a 1 h interval memory persists for 48 h (long-term memory, LTM). We found that if ITM training preceded LTM training, then LTM would persist for 24 h longer. This augmenting effect on LTM persistence could be demonstrated for up to 5 h following the last ITM training session, even though ITM was not observed at that time. However, if LTM training ensued 8 h after the last ITM training session, an augmented LTM did not occur. Extinguishing the memory produced by the ITM training procedure also prevented augmentation of LTM. That is, if an extinction procedure was given to the snails after the ITM training procedure, LTM did not persist longer than 48 h. Thus, at the behavioural level, ITM and LTM are interconnected.

Animals↗

PubMed2006

Why does brain damage impair memory? A connectionist model of object recognition memory in perirhinal cortex.

Object recognition is the canonical test of declarative memory, the type of memory putatively impaired after damage to the temporal lobes. Studies of object recognition memory have helped elucidate the anatomical structures involved in declarative memory, indicating a critical role for perirhinal cortex. We offer a mechanistic account of the effects of perirhinal cortex damage on object recognition memory, based on the assumption that perirhinal cortex stores representations of the conjunctions of visual features possessed by complex objects. Such representations are proposed to play an important role in memory when it is difficult to solve a task using representations of only individual visual features of stimuli, thought to be stored in regions of the ventral visual stream caudal to perirhinal cortex. The account is instantiated in a connectionist model, in which development of object representations with visual experience provides a mechanism for judgment of previous occurrence. We present simulations addressing the following empirical findings: (1) that impairments after damage to perirhinal cortex (modeled by removing the "perirhinal cortex" layer of the network) are exacerbated by lengthening the delay between presentation of to-be-remembered items and test, (2) that such impairments are also exacerbated by lengthening the list of to-be-remembered items, and (3) that impairments are revealed only when stimuli are trial unique rather than repeatedly presented. This study shows that it may be possible to account for object recognition impairments after damage to perirhinal cortex within a hierarchical, representational framework, in which complex conjunctive representations in perirhinal cortex play a critical role.

Brain Injuries↗

PubMed2004

Comparison of memory and combined exercise and memory-anchoring procedures on ratings of perceived exertion during short duration, near-peak-intensity cycle ergometer exercise.

The purpose of this study was to compare ratings of perceived exertion (RPE) following memory-anchoring and two different types of combined exercise and memory-anchoring during short duration, near-peak-intensity cycle exercise. Thirty recreationally trained males volunteered to participate. The M group, n = 10, received only verbal instructions prior to the experimental trial. The EM1 group, n = 10, and the EM2 group, n = 10, received the same verbal instructions, but these were administered while participants performed maximal, graded cycle ergometer exercise. The low perceptual anchor was established during light pedaling for both EM1 and EM2. The high perceptual anchor was established during the final stage of the maximal cycle test for EM1 and during a 30-sec. sprint immediately following the final stage of the maximal cycle ergometer testing for EM2. On the experimental trial pedaling at maximal intensity for 30-sec. was against a resistance equal to .10 x body mass (kg) on a cycle ergometer. The Borg 15-category RPE scale was used to record exertional perceptions. RPE was reported at 8, 13, 18, 23, and 28 sec. each trial. Ratings were similar among the three groups. Their linear regression slopes and intercepts were also similar. Memory-anchoring produced similar RPE for two different combined exercise and memory-anchoring procedures. In conclusion, memory-anchoring and combined exercise and memory-anchoring produce similar RPE during high intensity, short duration cycle exercise in young recreationally trained athletes.

Ergometry↗

PubMed2001

Immunological memory: contribution of memory B cells expressing costimulatory molecules in the resting state.

Traditionally, emphasis has been placed on the roles of Th cells in generating and amplifying both cellular and humoral memory responses. Little is known about the potential contributions of B cell subsets to immunological memory. Resting memory B cells have generally been regarded as poor APC, attributed in part to the relative paucity of costimulatory molecules identified on their surface. We describe a novel subpopulation of human memory B cells that express CD80 in their resting state, are poised to secrete particularly large amounts of class switched Igs, and can efficiently present Ag to and activate T cells. This functionally distinct B cell subset may represent an important mechanism by which quiescent human B cells can initiate and propagate rapid and vigorous immune memory responses. Finally, these studies extend recent observations in the murine system and highlight the phenotypic and functional diversity that exists within the human B cell memory compartment.

Antigen Presentation↗

PubMed2005

Molecular signatures distinguish human central memory from effector memory CD8 T cell subsets.

Memory T cells are heterogeneous in terms of their phenotype and functional properties. We investigated the molecular profiles of human CD8 naive central memory (T(CM)), effector memory (T(EM)), and effector memory RA (T(EMRA)) T cells using gene expression microarrays and phospho-protein-specific intracellular flow cytometry. We demonstrate that T(CM) have a gene expression and cytokine signaling signature that lies between that of naive and T(EM) or T(EMRA) cells, whereas T(EM) and T(EMRA) are closely related. Our data define the molecular basis for the different functional properties of central and effector memory subsets. We show that T(EM) and T(EMRA) cells strongly express genes with known importance in CD8 T cell effector function. In contrast, T(CM) are characterized by high basal and cytokine-induced STAT5 phosphorylation, reflecting their capacity for self-renewal. Altogether, our results distinguish T(CM) and T(EM)/T(EMRA) at the molecular level and are consistent with the concept that T(CM) represent memory stem cells.

CD8-Positive T-Lymphocytes↗