Primary Memory Research Articles

Simple and complex memory spans and their relation to fluid abilities: Evidence from list-length effects

Complex (working memory) span tasks have generally shown larger and more consistent correlations with higher-order cognition than have simple (or short-term memory) span tasks. The relation between verbal complex and simple verbal span tasks to fluid abilities as a function of list-length was examined. The results suggest that the simple span-fluid abilities correlation changes as a function of list-length, but that the complex span-fluid abilities correlation remains constant across list-lengths from lists as short as two items. Furthermore, regression and factor analytic results suggested that the longest simple span list-lengths and all of the complex span list-lengths had both unique and shared variability in predicting fluid abilities, but that estimates of primary memory did not uniquely predict fluid abilities. It is suggested that complex spans, generally, predict higher-order cognition to a greater extent than do simple spans because complex spans require retrieval of items that have been displaced from primary memory due to the processing component of these tasks. Items in simple spans will also be displaced from primary memory but only after primary memory has become overloaded.

Relative preservation of ‘animate’ knowledge in an atypical presentation of herpes simplex virus encephalitis

A comprehensive battery of neuropsychological tests designed to assess primary cognitive functions, including language and semantic memory, was given to MG, a patient with confirmed herpes simplex virus encephalitis. MG’s initial jargon aphasia resolved over time to leave her with a mild phonological impairment. She had a very mild amnesia that was worse for verbal material and a category-specific impairment of semantic memory. This latter impairment resulted in a significant anomia that was worse for manmade/artefact items than for animate kinds. Her naming difficulties were associated with a mild impairment in comprehension that was not specific to category or feature type. MRI revealed a strongly asymmetric and atypical distribution of pathology in MG with the disease affecting the left medial temporal lobe, temporal pole, left frontotemporal and temporoparietal regions.

Degree of inhibition of cortical acetylcholinesterase activity and cognitive effects by donepezil treatment in Alzheimer’s disease

Objectives: To determine in vivo cortical acetylcholinesterase (AChE) activity and cognitive effects in subjects with mild Alzheimer’s disease (AD, n = 14) prior to and after 12 weeks of donepezil...

Cognitive correlates of alterations in acetylcholinesterase in Alzheimer's disease

We recently reported findings of modest loss of cortical acetylcholinesterase (AChE) activity in patients with overall mild Alzheimer's disease (AD) using N-[ 11C]methyl-pi-peridin-4-yl propionate ([ 11C]PMP) AChE positron emission tomography (PET). To determine cognitive correlates of in vivo cortical AChE activity in patients with mild to moderate AD ( n = 15), and in normal controls (NC, n = 12) using [ 11C]PMP AChE PET imaging. Mean cortical AChE activity in the AD subjects was mildly reduced (−11.1%) compared to the control subjects ( P < 0.05). Analysis of the cognitive data showed that mean cortical AChE activity was significantly associated with performance on a test of attention and working memory (WAIS-III Digit Span, R = 0.46, P = 0.01) but not with tests of delayed short or long-term memory functions. Similar findings were present when the analysis was limited to the temporal cortex. Cortical AChE activity is more robustly associated with functions of attention and working memory compared to performance on primary memory tests in AD.

Cognitive impairment in preclinical Alzheimer's disease: A meta-analysis.

To determine the size of the impairment across different cognitive domains in preclinical Alzheimer's disease (AD), a meta-analysis based on 47 studies involving 9,097 controls and 1,207 preclinical AD cases was conducted. There were marked preclinical deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning; somewhat smaller deficits in verbal ability, visuospatial skill, and attention; and no preclinical impairment in primary memory. Younger age (< 75 years) and shorter follow-up intervals (< 3 years) were associated with larger effect sizes for both global cognitive ability and episodic memory. For global cognitive ability, studies that used population-based sampling yielded larger effect sizes; for episodic memory, larger differences were seen in studies that preidentified groups in terms of baseline cognitive impairment. Within episodic memory, delayed testing and recall-based assessment resulted in the largest effect sizes. The authors conclude that deficits in multiple cognitive domains are characteristic of AD several years before clinical diagnosis. The generalized nature of the deficit is consistent with recent observations that multiple brain structures and functions are affected long before the AD diagnosis.

Optimized neuropsychological procedures at different stages of dementia diagnostics

Objective To establish a staged procedure in dementia diagnostics and to propose specific, abbreviated test batteries suitable for the three diagnostic stages: Primary medical care, neuro-psychiatry, and memory clinic. Methods A total of 159 participants underwent comprehensive clinical, neurological, neuropsychological, and MRI examinations. The neuropsychological examination took approximately 90 min per individual and was based on tests of verbal and visual memory, language, abstract thinking, attention, visuo-constructive and spatial functions. Stepwise discriminant analyses were performed to identify which subset of the 18 variables of the comprehensive test battery was the most appropriate to differentiate between specific diagnostic groups, and which variables could be discarded to abbreviate the test battery without substantial loss in diagnostic accuracy. Results The abbreviated versions of the test battery retained adequate diagnostic accuracy. The accuracy decreased by maximally 4%, whereas the test administration time dropped substantially from previously 90 min to a maximum of 50 min. Conclusion Depending on the diagnostic question, a specifically abbreviated version of the comprehensive test battery can be used without unacceptably reducing diagnostic accuracy.

On time, memory and dynamic form

A common approach to explaining the perception of form is through the use of static features. The weakness of this approach points naturally to dynamic definitions of form. Considering dynamical form, however, leads inevitably to the need to explain how events are perceived as time-extended—a problem with primacy over that even of qualia. Optic flow models, energy models, models reliant on a rigidity constraint are examined. The reliance of these models on the instantaneous specification of form at an instant, t, or across a series of such instants forces the consideration of the primary memory supporting both the perception of time-extended events and the time-extension of consciousness. This cannot be reduced to an integration over space and time. The difficulty of defining the basis for this memory is highlighted in considerations of dynamic form in relation to scales of time. Ultimately, the possibility is raised that psychology must follow physics in a more profound approach to time and motion.

Human in vivo-activated CD45R0(+) CD4(+) T cells are susceptible to spontaneous apoptosis that can be inhibited by the chemokine CXCL12 and IL-2, -6, -7, and -15.

The number of T cells that have undergone proliferation after antigen stimulation in vivo must be controlled to prevent excessive accumulation of T cells, autoimmunity, and T cell neoplasia. We describe here that primary human adenotonsillar memory phenotype CD45R0(+) CD4(+) T cells, but not adenotonsillar naive-phenotype CD45RA(+) CD4(+) T cells, or peripheral blood naive or memory CD4(+) T cells, express high levels of activation-associated antigens CD38, CD69, CD71, and HLA-DR. These in vivo-activated CD45R0(+) CD4(+) T cells were susceptible to spontaneous and rapid apoptosis in vitro. Apoptosis could not be inhibited by the disruption of Fas-Fas ligand engagement or by the pan-caspase inhibitor ZVAD. Cross-linking of the T cell antigen receptor did not rescue cells from apoptosis. Apoptosis could be partially inhibited by the chemokine CXCL12/SDF-1, by IL-6, and by the IL-2 receptor common gamma chain-signaling cytokines IL-2, -7, and -15. Inhibitors of phosphatidylinositol 3-kinase accelerated apoptosis. We conclude that after in vivo activation of CD45R0(+) CD4(+) T cells, the cells experience a period of intrinsically elevated sensitivity to apoptosis and that multiple external signals control their survival.

Validation of the Korean version of the Syndrom Kurztest (SKT): a short test for the assessment of memory and attention.

The Syndrom Kurztest SKT is a brief neuropsychological test battery that consists of nine subtests and defines two independent factors of memory and attention deficit. The aim of this study was to validate the Korean version of the SKT. The reliability of each subtest among three parallel Forms (A, B and C) of the Korean version was high (r = 0.46-0.95). The SKT had good concurrent validity with the Mini-Mental State Examination (r = -0.83, p < 0.001). Factor analysis confirmed the presence of two primary factors, memory and attention. The overall similarities of the factor structures for the Korean data and those for the data from Germany and the USA provide evidence of the transcultural stability of the SKT.

Formalization of computer input and output: the Hadley model

Current digital evidence acquisition tools are effective, but are tested rather than formally proven correct. We assert that the forensics community will benefit in evidentiary ways and the scientific community will benefit in practical ways by moving beyond simple testing of systems to a formal model. To this end, we present a hierarchical model of peripheral input to and output from von Neumann computers, patterned after the Open Systems Interconnection model of networking. The Hadley model categorizes all components of peripheral input and output in terms of data flow; with constructive aspects concentrated in the data flow between primary memory and the computer sides of peripherals' interfaces. The constructive domain of Hadley is eventually expandable to all areas of the I/O hierarchy, allowing for a full view of peripheral input and output and enhancing the forensics community's capabilities to analyze, obtain, and give evidentiary force to data.

Memory profiles in parents of patients with schizophrenia

Recent research shows that categorizing patients with schizophrenia based on frontal–striatal and frontal–temporal memory profiles may yield neurobiologically meaningful disease subtypes. We hypothesize that parents of patients exhibit similar memory profiles. Both parents of 36 patients with schizophrenia ( N=72) and 26 healthy married control couples ( N=52) participated in this study. All subjects were physically healthy and had no history of neurological illness or alcohol/drug abuse. The presence of a psychiatric and/or personality disorder was assessed with the Comprehensive Assessment of Symptoms and History (CASH) interview, the Schedule for Affective Disorders and Schizophrenia-lifetime (SADS-L) interview and the Structured Interview for DSM-IV Personality Disorders (SIDP-IV), respectively. Cluster analysis of selected measures from the Dutch version of the California Verbal Learning Test (CVLT) delineated parents into two subgroups with distinct memory deficits and a third subgroup without impairments. Specific frontal–striatal and frontal–temporal subgroups, however, were not found. In addition, our results indicated that mothers seem to be more protected against the negative effects of genetic liability to schizophrenia than fathers. Furthermore, relatives with a higher level of intelligence may have more cognitive reserve to compensate for the negative impact of implied brain dysfunction on verbal memory than relatives with a low level of intelligence. Although the parents of patients with schizophrenia could be delineated into subgroups with primary memory deficits, frontal–striatal and frontal–temporal subgroups could not be unambiguously identified. The association that emerged between level of intelligence, gender and severity of memory impairment deserves further exploration.

Interference with spatial working memory: an eye movement is more than a shift of attention.

In the present experiments, we examined whether shifts of attention selectively interfere with the maintenance of both verbal and spatial information in working memory and whether the interference produced by eye movements is due to the attention shifts that accompany them. In Experiment 1, subjects performed either a spatial or a verbal working memory task, along with a secondary task requiring fixation or a secondary task requiring shifts of attention. The results indicated that attention shifts interfered with spatial, but not with verbal, working memory, suggesting that the interference is specific to processes within the visuospatial sketchpad. In Experiment 2, subjects performed a primary spatial working memory task, along with a secondary task requiring fixation, an eye movement, or an attention shift executed in the absence of an eye movement. The results indicated that both eye movements and attention shifts interfered with spatial working memory. Eye movements interfered to a much greater extent than shifts of attention, however, suggesting that eye movements may contribute a unique source of interference, over and above the interference produced by the attention shifts that accompany them.

Use of the Everyday Memory Questionnaire With Children

The Everyday Memory Questionnaire (EMQ; Sunderland, Harris, & Baddeley, 1983) was examined for its suitability to assess children's memory. The parents of 226 school children (6-12 years) completed the EMQ in relation to their own children. A subset of these children (N=101), in 6, 8 and 10 years age groups, completed subtests of the Wide Range Assessment of Memory and Learning (WRAML; Sheslow & Adams, 1990). Comparison of EMQ and WRAML data found aspects of verbal memory correlated moderately with the EMQ in the 10 years age group. There were no meaningful correlations in the 8 years age group. In the 6 years age group aspects of visual memory correlated moderately with the EMQ. The diagnostic utility of the EMQ for children was assessed by comparing the school group to children diagnosed with ADHD and/or learning disorders. Diagnostic indicators revealed the EMQ to have high sensitivity (89%) but poor positive predictive power, identifying 40% of the school group as having memory deficits. Negative predictive power (confirming a negative diagnosis) was high. Validity data suggested that the EMQ could be useful with children at least as young as 10 years and further research needs to be conducted to establish the utility of the EMQ in clinical groups with primary memory deficits.

IL-15 is superior to IL-2 in the generation of long-lived antigen specific memory CD4 and CD8 T cells in rhesus macaques

Using tetanus toxoid (TT) and influenza (Flu) immunization of rhesus macaques as a model, the effect of IL-2 and IL-15 on the generation and maintenance of antigen specific memory T cells was evaluated following primary and secondary immunization. Daily cytokine administration expanded primarily effector but not memory cells, while spacing cytokine administration to q3–7 days markedly enhanced TT and Flu specific memory responses. Following primary immunization, TT specific CD4 and influenza matrix protein (Flu-MP) specific CD8 effector responses were enhanced by IL-2 administration but CD8 specific memory responses were no different from cytokine non-treated monkeys. In contrast, expansion of Flu specific CD8 cells with IL-15 was only modest but resulted in significantly elevated levels of memory cells at 6 months. IL-15 also significantly enhanced early and late TT specific CD4 responses. The highest levels of primary effector and memory T cells were observed following alternate administration of both IL-2 and IL-15. Following booster immunization, however, only IL-15 appeared able to enhance CD8 T cell responses while IL-2 or IL2/IL-15 administration were less effective.

Cognitive test performance in relation to psychotic symptoms and paranoid ideation in non-demented 85-year-olds

Clinical studies suggest that psychotic and paranoid states in late life are associated with cognitive dysfunction. However, it is not clear whether this finding would be observed in general population samples of non-demented elderly, particularly after adjustment for potential confounding factors. A representative sample of non-demented 85-year-olds living in the community or in institutions in Göteborg, Sweden (N = 347) was examined using a psychiatric and physical examination (including a medical history), key-informant interview, psychometric testing and review of medical records. Individuals with psychotic symptoms and paranoid ideation were compared with the mentally healthy regarding tests of verbal ability, inductive logical reasoning, spatial ability, perceptual speed, basic arithmetic, primary memory and secondary memory. Non-demented 85-year-olds with psychotic symptoms or paranoid ideation performed specifically worse on tests measuring verbal ability, logical reasoning and two tests of spatial ability after adjustment for sex, education, hearing impairment, visual deficits, somatic disorders, depression, 3-year-mortality rate and incident dementia. Psychotic symptoms and paranoid ideation were associated with lower performance on cognitive tests related to verbal ability, logical reasoning and spatial ability in non-demented 85-year-olds after adjustment for potential confounders.

Drugs and human memory (part 1): Clinical, theoretical, and methodologic issues.

Drugs and human memory (part 1): Clinical, theoretical, and methodologic issues.

Use of recombinant cytokines for optimized induction of antiviral immunity against SIV in the nonhuman primate model of human AIDS.

Outbreaks of infectious diseases such as HIV and the much televised and attention-getting outbreaks of diseases such as Ebola, Hantaviruses, and the most recent outbreak of SARS have induced a significant new interest in the formulations and more importantly the science of vaccinology, which has previously to a large extent been conducted empirically. Our laboratory has focused on the use of recombinant nonhuman primate cytokines as adjunctive therapies for inducing antigen-specific immune responses in monkeys because most recombinant human cytokines appear to be immunogenic. This article provides a summary of our work with such cytokines, which includes attempts to define optimum dosing schedules that lead to optimal primary and lasting memory antigen-specific immune responses.

Environmental Influences on Primary Memory Development: A Cross-Cultural Study of Memory Span in Lao and American Children

Although research examining Auditory-Verbal and Visual Memory Span in adults has failed to provide compelling evidence for the modality specificity of such tasks, Fastenau, Conant, and Lauer (1998) suggested that these processes may be dissociable in children until around the age of 8 years when visuospatial memory span appears to become more verbally mediated perhaps as a function of formal reading training. A subsequent cross-cultural study in Zaïre (now Democratic Republic of Congo) by Conant and colleagues (1999) supported that hypothesis. However, other differences in the sociocultural environments of American and rural Zaïrian children such as nutritional and health care factors could potentially account for the findings. The present study examines the relationships among Auditory-Verbal, Visual, and Cross-Modal Memory Span tasks with 46 Lao and 56 American children. Both samples were divided into younger and older groups, and separate partial correlational analyses were performed on Kaufman Assessment Battery for Children (K-ABC) data from each group. In younger Lao and American children, Auditory-Verbal Memory Span was not significantly correlated with Visual Memory Span or Cross-Modal Memory Span, whereas significant correlations were found between Auditory-Verbal Memory Span and these other tasks in older children from both countries. The similar pattern in both cultures, together with findings from Zaïre, supports the hypothesis that the relationship between Auditory-Verbal and Visual Memory Span may change with reading training.

Memory impairment suggests hippocampal dysfunction in abstinent ecstasy users

Previous studies have consistently shown impairments of memory and learning in regular users of the neurotoxic drug ecstasy (3,4-methylenedioxymethamphetamine [MDMA]). In addition, deficits in working memory, planning ability and central executive control, as well as high cognitive impulsivity, were also reported in some studies. Hence, the memory decrements may be secondary due to other cognitive failures. The purpose of this study was to analyze the nature of the cognitive deficits of ecstasy users. Tests of memory, working memory, central executive function and cognitive impulsivity were administered to 60 currently abstinent ecstasy users and to 30 nonusers. Heavy ecstasy users ( n=30, lifetime dose ≥80 ecstasy tablets) had lower memory performance than both nonusers and moderate users ( n=30, lifetime dose <80 ecstasy tablets). In contrast, we found no group differences in central executive function, working memory, planning ability and cognitive impulsivity between ecstasy users and controls. Poorer memory and working memory performance was associated with a heavier pattern of ecstasy use. Low working memory, planning ability and central executive control and high cognitive impulsivity did not predict poor memory performance. Our results indicate primary memory dysfunction in heavy ecstasy users, which may be related to a particularly high vulnerability of the hippocampus to the neurotoxic effects of MDMA. Hippocampal dysfunction after ecstasy use may be a risk factor for earlier onset and/or more severe age-related memory decline in later years.

Terminal decline and cognitive performance in very old age: does cause of death matter?

Cross-sectional differences and longitudinal changes in cognitive functioning in relation to mortality across a 7-year follow-up period, with 3 times of measurement, were examined in a population-based sample of very old adults. The authors also sought to determine whether cause of death (cerebro/cardiovascular disease [CVD]; non-CVD) modified the magnitude of mortality-related cognitive deficits. Cognitive performance was indexed by tests of general cognitive ability, episodic memory, primary memory, verbal fluency, and visuospatial ability. Results indicated cross-sectional differences on all domains of functioning, with persons who would die within 3 years after baseline testing performing more poorly. Longitudinally, greater decrements were observed on all domains for persons who would die after the first follow-up period, as compared with survivors. Cause of death failed to modify the magnitude of the cross-sectional and longitudinal deficits. The pattern of results point to the general nature of this phenomenon.