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At least 649 records · Page 36Linked to original sources
PubMed1999

Altered memory T cell differentiation in patients with early rheumatoid arthritis.

The chronic immune response in rheumatoid arthritis (RA) might be driven by activated Th1 cells without sufficient Th2 cell differentiation to down-modulate inflammation. To test whether disordered memory T cell differentiation contributes to the typical Th1-dominated chronic inflammation in RA we investigated differentiation of resting CD4+ memory T cells in patients with early (6 wk to 12 mo) untreated RA and in age- and sex-matched healthy controls in vitro. No difference in cytokine secretion profiles of freshly isolated memory T cells was detected between patients and controls. A cell culture system was then employed that permitted the differentiation of Th effectors from resting memory T cells by short term priming. Marked differences were found in response to priming. Th2 cells could be induced in all healthy controls by priming with anti-CD28 in the absence of TCR ligation. By contrast, priming under those conditions resulted in Th2 differentiation in only 9 of 24 RA patients. Exogenous IL-4 could overcome the apparent Th2 differentiation defect in seven patients but was without effect in the remaining eight patients. In all patients a marked decrease in IL-2-producing cells and a significant increase in well-differentiated Th1 cells that produced IFN-gamma but not IL-2 were evident after priming with anti-CD3 and anti-CD28. The data suggest that CD4+ memory T cells from patients with early untreated RA manifest an intrinsic abnormality in their ability to differentiate into specific cytokine-producing effector cells that might contribute to the characteristic Th1-dominated chronic (auto)immune inflammation in RA.

Adult↗
PubMedDate not supplied

[Neuropsychological tools for the study of depression].

Depression is a common disorder, affecting approximately one in ten of the population at some time in their lives. The nature and extent of such changes, however, is less clear, and their specificity to mood disorder, their existence before the onset of affective symptoms, their etiology and their relation ship to underlying neuroanatomical abnormalities remain poorly understood. Our objective is to present a comprehensive review of the existing neuropsychological literature on bipolar affective disorder, mayor depression and the differential diagnosis between geriatric depression and the depression as early symptom of Alzheimer's disease. The most critical neuropsychological assessment to study this patients will be discussed. Depression is associated with dysexecutive syndrome which correlate with fronto subcortical diseases. Cognitive impairment include attention disorders, memory difficulties type forgetfulness and executive dysfunction (planning and executions of complex behaviors, monitoring of performance, feedback, decision making etc). Cortical neuropsychological profile in a depressive patients represent Alzheimer's disease associate. Neuropsychological assessment is useful to detect both different cognitive profiles (Cortical vs Subcortical).

Attention↗
PubMed2001

Frequency-specific effects of flicker on recognition memory.

The functions of the electroencephalographic rhythms are uncertain. Correlational evidence has linked 10-12Hz alpha rhythms to memory formation in healthy people. Moreover, loss of 10Hz alpha correlates with memory problems in Alzheimer's disease. Going beyond mere correlation, brain stimulation or peptides that alter electroencephalographic rhythms can modulate behaviour and enhance memory in rats. This latter finding fits with evidence that electroencephalogram-frequency stimulation can enhance long-term potentiation, the neural basis of memory. I aimed to test if manipulations of alpha-frequency electroencephalographic activity enhance human memory. Flicker provides an experimental means of modulating the human electroencephalogram: 9-12Hz flicker can entrain alpha-like activity. In rats, the frequency-specificity of brain stimulation's behavioural effects excludes the possibility that they result from non-specific (i.e. non-electroencephalographic) mechanisms. I tested if flicker manipulations would show analogous frequency-specific effects in man. In view of the above correlational data, I predicted that flicker at 10Hz (a frequency near to the peak power of endogenous alpha) would enhance human memory, but adjacent frequencies (8.7 and 11.7 Hz) would not. The results confirmed this prediction. This suggests that 10Hz electroencephalographic alpha subserves memory formation in man: 10Hz flicker enhances memory in healthy people and may have therapeutic potential in memory disorders.

Adult↗
PubMedDate not supplied

Mental impairment (dementia) and cerebral atrophy in geriatric patients.

In predicting the degree of brain atrophy as measured by CT, the AGP score and a few clinical variables were of some remarkable value. Especially the variables related to memory disorders and lack of insight are easily and reliably assessed during the course of the examination. In comparison to other more widely used neurological methods, the FHT proved to be an effective device for detecting brain atrophy, whereas the PMR and the glabellar blink were less effective. The close correlations between cerebral atrophy as measured by CT and a considerable number of clinical variables support the opinion that the organic substratum is not inconsistent with the clinically assessed function. Further research using strictly defined and standardized quantitative methods of psychopathological as well as neuroradiological assessment would seem to be a most promising attempt to answer the questions here only touched upon.

Aged↗
PubMed2001

A slow wave investigation of working memory biases in mood disorders.

Mood-congruent working memory biases were examined in a delayed matching to sample paradigm using the slow wave (SW) event-related brain potential (ERP) component. Mood-congruent working memory biases, indexed by SW amplitudes, were demonstrated among individuals experiencing a major depressive episode (MDE) and nondepressed controls but not individuals with dysthymia. However, analyses of symptom severity demonstrated that those with dysthymia exhibited significantly less negative SW amplitudes with increasing depressive mood severity, whereas individuals with major depression demonstrated more negative SW amplitudes with increasing depressive mood severity. These results are discussed in the context of diagnostic specificity for cognitive biases associated with working memory of mood-disordered individuals.

Adult↗
PubMed1998

A role for the hippocampal formation in implicit memory: a 3-D PET study.

The apparent preservation of word priming effects in amnesia has been interpreted as supporting the view that implicit memory depends on brain systems that are independent of mesial temporal lobe structures which are in part responsible for explicit memory disorders. Nevertheless, a number of studies have demonstrated word priming deficits in amnesic patients relatively to normal subjects, suggesting that such structures may also be involved in implicit memory. To determine whether one such structure, the hippocampal formation, is a component of the brain system subserving word priming, a 3-D PET study was carried out in 13 normal individuals. Encoding was carried out using the brief multiple presentation technique, a procedure that allows one to effectively circumvent contamination of implicit memory tasks by explicit memory strategies. Results revealed that word priming was indeed associated with an activation of the right hippocampal formation. This finding of an hippocampal involvement in word priming calls into question the notion of absolute dissociability between the brain systems underlying performance on various explicit and implicit memory tasks.

Adolescent↗
PubMedDate not supplied

[Disordered higher mental functions in lesions of different parts of the caudate nucleus].

The relation between deterioration in higher mental functions and localization of the brain pathological process was studied in 22 patients with arteriovenous malformation in the head or/and the body of the caudate nucleus using the methods of multivariate statistics and structurally organized neuropsychological information. It was shown that the lesions in the caudate nucleus body resulted in disturbances of the spatial functions. Pathological foci in the head of the caudate nucleus were associated with memory disorders (the right-side foci were accompanied by deterioration in the visual memory and the left-side ones by that in the audio-verbal memory) and modification of programming and control of voluntary activity.

Adolescent↗
PubMed1996

CR 2249: a new putative memory enhancer. Behavioural studies on learning and memory in rats and mice.

The effects of S-4-amino-5-[4,4-dimethylcyclohexyl)amino]-5-oxopentanoic acid (CR 2249), a new entity selected from a new series of glutamic acid derivatives, has been investigated in different paradigms for screening nootropics. CR 2249 ameliorated the memory retention deficit produced by scopolamine in step-through-type passive avoidance in rats and by electroconvulsive shock in step-down-type passive avoidance in mice. CR 2249 was also capable of improving performance in behavioural tests of learning and memory in the absence of cholinergic hypofunction or cognitive deficit. The activity was determined using different passive and active avoidance behavioural test procedures on rats. CR 2249 was active only when given 45 min before training and did not show any effect when administered immediately after the learning training or before the retention trial. No changes in the general behaviour or motor activity of the animals were observed, indicating that CR 2249 effects cannot be attributed to sensory-motor deficit. Microdialysis experiments have shown that CR 2249 significantly increased noradrenaline release in the hippocampus of freely moving rats and reduced 3,4-dihydroxyphenylglycol efflux. These effects have led us to hypothesize that CR 2249 memory effect might be mediated by a direct or indirect action on noradrenergic transmission. These behavioural results suggest that this new agent has clinical application in memory disorders.

Animals↗
PubMed1997

Severe anterograde amnesia with onset in childhood as a result of anoxic encephalopathy.

Our patient (M.S.) had an abrupt onset of amnesia due to a respiratory arrest at the age of 8 years and has been followed by one of us (A.L.R.) for 19 years. A specially designed MRI study indicated that the neuroanatomical localization of his lesion is restricted to the hippocampal formation bilaterally. Comparison of M.S.'s present IQ and academic scores with earlier scores revealed that his literacy skills, certain basic language functions and vocabulary development were arrested by his memory disorder. In contrast, development of mathematical skill was less curtailed, and verbal and nonverbal logical abilities developed to adult levels. Neuropsychological examination at the age of 27 years elicited a pattern of memory deficits similar to those found in a case (H.M.) of known mesial temporal lobe damage in adulthood. The neuropsychological pattern revealed those aspects of cognitive development that do, and those that do not, require intact memory. The limitations to intellectual development imposed by severe amnesia in childhood are not pervasive, but rather, are limited to specific types of abilities.

Adult↗
PubMed1982

Habituation of exploratory activity in mice: a screening test for memory enhancing drugs.

The habituation of exploratory activity was investigated as an experimental model of memory processes. Mice were given two sessions in a simple photo-cell activity cage and the decrease in activity at the second session (habituation) served as an index of retention. Retention decreased as the interval between sessions increased from 1 to 7 days. Retention was facilitated or impaired by post-session. IP injections of several drugs known respectively to improve [(+)-amphetamine, nicotine, physostigmine, strychnine] or impair (chlordiazepoxide, chlorpromazine, scopolamine) memory in other animal models. Memory facilitation or impairment only occurred if administration of the enhancing or impairing agent closely followed the first session, suggesting that the consolidation period was of limited duration. Post-session administration of presumably rewarding or noxious stimuli did not affect retention. Finally, retention was enhanced by several drugs which are used clinically for the treatment of memory disorders (bromocriptine, dihydroergotoxine, meclofenoxate, naftidrofuryl and piracetam). These results, consistent with classical learning data, suggest that habituation of exploratory activity in mice provides a simple but valid model of memory processes suitable for the screening of memory enhancing drugs.

Animals↗
PubMed2001

Patterns of verbal learning and memory in traumatic brain injury.

CVLT and WMS-R Digit Span variables were used to calculate indexes of seven specific short- and long-term memory processes: working memory span and central executive functions, and long-term memory encoding, consolidation, retention, retrieval, control abilities. Scores on these indexes were then cluster-analyzed to determine whether subtypes of memory performance exist that correspond to deficits in these theoretical memory constructs. Parallel analyses were conducted with two large samples (N = 150 and N = 151) of individuals who had sustained a traumatic brain injury (TBI). Findings showed that TBI results in subgroups of memory disorders with specific deficits in consolidation, retention, and retrieval processes. Control problems (keeping track of list versus non-list items) only appeared in conjunction with retrieval deficits. Working memory span and central executive functioning (i.e., the ability to manipulate information in working memory) do not appear to be deficits characteristic of TBI as no such clusters emerged in the analyses. By using specific indexes of memory processes, and in contrast to previous studies, patterns of memory dysfunction were found that correspond to deficits in theoretically meaningful memory constructs.

Adult↗
PubMed1992

Neurology of memory.

This review discusses the neurological basis of human memory focusing on brain-behavior relations as revealed in patients with memory disorders due to brain lesions. A few relevant animal studies are also discussed. Recent studies are reviewed that provide new insights into the anatomic, chemical, and psychological organization of memory in health and neurological diseases.

Animals↗
PubMed1992

Enhancement of working memory performance in the rat by MDL 26,479, a novel compound with activity at the GABAA receptor complex.

MDL 26,479, a novel triazole compound with action at the GABAA receptor complex, was examined in 2 models of working memory deficit in the rat. MDL 26,479 attenuated a scopolamine-induced acquisition deficit in a T-maze reinforced alternation task. MDL 26,479 also reversed a performance deficit induced by increased delay between sample and choice trials in the same task, suggesting that the compound may have memory enhancing potential. This finding further supports claims that drugs acting at the GABAA receptor complex are of potential use in the treatment of memory disorder.

Animals↗
PubMed2002

[Volumetric measurements of the hippocampus and amygdala with MRI in healthy adults].

INTRODUCTION: Volumetric analysis of brain magnetic resonance images (MRI) measures structural changes associated with neurological and neuropsychiatric disorders. In recent years several studies have shown the utility of the volumetric measurement of the medial temporal lobe structures, especially the amygdala and the hippocampus in temporal lobe epilepsy, memory disorders, Alzheimer disease and schizophrenia. AIM: The purpose of this study was to measure and establish our normal values of the hippocampus and amygdala volumes. METHODS: All studies were performed using a 1.0 T Siemens unit with FISP 3D sequence. One millimeter, contiguous coronal scans of 40 healthy volunteers aged 19-26 years were obtained. The regions of interest were outlined using a mouse driven cursor. To determine the anatomic boundaries of the hippocampus and the amygdala the authors followed a generally accepted protocol previously described by C. Watson. RESULTS: The mean right and left hippocampal volumes were 2.12 cm3 (SD = 0.31) and 2.07 cm3 (SD = 0.3) and the mean right and left amygdaloid volume were 1.19 cm3 (SD = 0.19) and 1.2 cm3 (SD = 0.2) respectively. The mean asymmetry between the right and left hippocampus and amygdala was 3.17% and 3.48%, respectively. The inter-observer reliability range (alpha) was between 0.97 and 0.77. Subregional analysis of hippocampus was calculated as well. CONCLUSIONS: Normal volumetric data measured in our study fell in the midrange of the values in the literature. The volumetric analysis of the hippocampal subregions may allow assessment of providing more sensitive determination of the atrophic area, which may be important in epileptic disorders.

Adult↗
PubMed1988

[Alzheimer's disease with early association of a hemi-parkinsonian syndrome].

A 66 year-old woman presented with severe memory disorders followed several months later with tremor of Parkinsonian type of the right upper limb totally relieved by treatment with levodopa-benserazide. Four years later she was admitted with memory disturbances, temporospatial disorientation, constructional and ideatory apraxia, dressing apraxia and language difficulties. Eight years later she had become bed-ridden, with deviation of head and eyes towards the left, hypertonus tremor and stereotyped movements. Neuropathologic examination showed neuronal loss in substantia nigra and left locus ceruleus, dorsal nucleus of the pneumogastric nerve and Meynert's basal nuclei on both sides. Neurofibrillary tangles affected the peri-aqueductal grey matter and Lewy's bodies were observed in the substantia nigra. Neurofibrillary tangles and granulovacuolar degeneration together with senile plaques were numerous in the hippocampus, but senile plaques and neurofibrillary tangles were rare in the remainder of the cortex. Combined Alzheimer's disease and Parkinson's disease could be due to simple coincidence, one of the diseases possibly predisposing to the appearance of the other.

Aged↗
PubMed2001

[Behavioral disorders caused by acute and chronic manganese intoxications of white rats].

Single per oral administration of manganese chloride induced an obvious reversible diminishing of locomotor activity in white rats as well as deterioration of avoidance response to unconditioned and conditioned stimuli, prolongation of the conditioning latency, and a temporary deterioration of learning. Chronic manganese intoxication produced an irreversible learning disability and a slight memory disorders.

Animals↗
PubMed2005

Years of severe and isolated amnesia can precede the development of dementia in early-onset Alzheimer's disease.

A young patient with a severe and isolated memory disorder, meeting the criteria for MCI, was followed for a period of 8 years. His overall functional level remained stable with a CDR-score at 0.5 until the last year when it dropped to 1.0. Neuropsychological testing showed severe memory deficits but otherwise normal cognitive functions. Only minimal progression was measured; however, the last testing showed impaired abstraction and executive functioning as well as discrete problems generating names of objects and people. Neuroimaging, with MRI and SPECT, was consistent with a progressive degenerative disorder, and cerebrospinal fluid levels of beta-amyloid 1-42, tau protein, and phosphorylated tau protein were characteristic of Alzheimer's disease (AD). We argue that this is a case of prodromal AD, which illustrates an extreme version of the normal course with respect to slow progression of the disease and severity of amnesia early in the course.

Alzheimer Disease↗