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PubMed1992

A model-based study of learning and memory following transient global amnesia attacks.

Verbal learning and forgetting were studied in patients one month after an episode of Transient Global Amnesia and in normal control subjects by means of a two-stage stochastic model, which allows independent measurements of encoding, storage and forgetting. We preliminarily ascertained both the necessity and the sufficiency of the model to account for several performance scores of the two experimental groups, and then compared the learning and forgetting functions between groups. In spite of the analytical power of the statistical method adopted. Transient Global Amnesia was not found to entail persistent impairment of encoding and storage, as well as of retaining memory traces and retrieval algorhythm.

Cerebral Cortex↗
PubMed2006

Brahmi rasayana improves learning and memory in mice.

Cure of cognitive disorders such as amnesia, attention deficit and Alzheimer's disease is still a nightmare in the field of medicine. Nootropic agents such as piracetam, aniracetam and choline esterase inhibitors like Donepezil are being used to improve memory, mood and behavior, but the resulting side effects associated with these agents have made their use limited. The present study was undertaken to assess the potential of Brahmi rasayana (BR) as a memory enhancer. BR (100 and 200 mg kg(-1) p.o.) was administered for eight successive days to both young and aged mice. Elevated plus maze and passive-avoidance paradigm were employed to evaluate learning and memory parameters. Scopolamine (0.4 mg kg(-1) i.p.) was used to induce amnesia in mice. The effect of BR on whole brain AChE activity was also assessed. Piracetam (200 mg kg(-1) i.p.) was used as a standard nootropic agent. BR significantly improved learning and memory in young mice and reversed the amnesia induced by both scopolamine (0.4 mg kg(-1) i.p.) and natural aging. BR significantly decreased whole brain acetyl cholinesterase activity. BR might prove to be a useful memory restorative agent in the treatment of dementia seen in elderly.

Journal Article↗
PubMedDate not supplied

Learning and memory in rats exposed pre- and postnatally to alcohol. An attempt at pharmacological control.

Using conditioned-reflex methods for active and passive avoidance with punishment reinforcement, we found pronounced memory deficits in 12-week old rats exposed perinatally to alcohol (FAS rats). Impairment of memory was observed not only with the high dose of 9 g ethanol/kg body weight (ingested with tap water in a 6% solution) to which dams were exposed during pregnancy and lactation, but also with the ten-fold lower dose of 1 g ethanol/kg body weight (0.6% ethanol). The nootropic drugs citicholine, piracetam and meclofenoxate administered orally for five days before the training session were effective in decreasing memory deficits; particularly pronounced was the effect of piracetam and meclofenoxate. The benzodiazepine tranquilizer diazepam additionally impaired learning and memory in FAS rats. It is suggested that nootropics could be used to decrease the cognitive disturbances in some humans born to alcoholic mothers.

Animals↗
PubMed1997

Differential involvement of left temporolateral and temporomesial structures in verbal declarative learning and memory: evidence from temporal lobe epilepsy.

A wealth of animal and human research has pointed to a significant involvement of the temporal lobes in memory processing, and yet the different functional roles of temporal cortical vs. mesial structures remain unclear. We studied verbal declarative memory, by using a word list paradigm that differentiates among learning (immediate recall), memory (delayed recall), and recognition, in epilepsy patients being considered for surgical resection of the left temporal lobe. Verbal memory was evaluated preoperatively and during the recording of intracranial event related potentials and postoperatively after selective hippocampectomy, temporal cortical lesionectomy, or anterior two-thirds en bloc temporal lobe resection procedures. Preoperative differences in verbal memory performance as a function of differences in underlying neuropathology, concurrent event-related potentials, and specific patterns of postoperative memory impairments lead to converging evidence that verbal declarative memory relies on a synergistic interaction of at least two functionally distinct brain systems. Material-specific data acquisition, or working memory, is mediated by neocortical temporal structures, whereas long-term consolidation/retrieval is particularly mediated by temporomesial structures. In contrast to the left temporal neocortex, the function of the temporomesial system appears to be material nonspecific. Apparently, its preferential involvement in verbal memory is due to its close interaction with overlying neocortical structures that are specialized for language processing.

Adult↗
PubMed1990

Neurobehavioral studies of forced swimming: the role of learning and memory in the forced swim test.

1. Immobility in the forced swim test ("behavioral despair test") has often been regarded as an animal model of despair or depression. 2. Behavioral studies of forced swimming ("behavioral despair") are reviewed and compared with certain behavioral effects of exposure to inescapable shock (i.e., "learned helplessness"). 3. Exposure to inescapable shock clearly impairs subsequent coping responses. However, detailed behavioral studies of forced swimming indicate that immobility during forced swimming is not a failure of coping but instead reflects a relatively successful coping strategy that employs energy conserving behaviors. 4. Certain neurobiological studies of forced swimming are reinterpreted in light of the behavioral evidence that immobility during forced swimming reflects effects of learning and memory rather than effects of despair or depression. 5. Some implications for future neurobehavioral studies of forced swimming and uncontrollable shock are discussed.

Animals↗
PubMed2002

Learning and memory in disease vectors.

All animals can learn to some extent and it should not be surprising to discover that important vectors can also be influenced by experience. The potential effect of memory on vector behaviour, particularly vectorial capacity, has barely been investigated. Yet, how a population of blood-feeding insects distributes between available resources has important epidemiological consequences. Several recent studies have shown that behaviour during oviposition site-selection, host location and even host choice can be influenced by the environment or by experience after eclosion. The significance of these studies and their consequences for epidemiology and control are considered here.

Animals↗
PubMed2003

Cognitive style, working memory and learning behaviour and attainment in school subjects.

BACKGROUND: Both working memory capacity and cognitive style have independently been found to affect performance on school-type tasks, but their effects in interaction have not been considered. AIMS: The aims of this study were to consider the relationship between working memory, cognitive style and gender on (a) overall learning behaviour, and (b) performance on a range of school subjects. SAMPLE: The sample comprised 206 13-year-old secondary comprehensive school Year 8 pupils, being all pupils in that year who completed the principal assessments. METHOD: The pupils did an assessment of working memory efficiency - the Information Processing Index (Riding, 2000a). They also completed the Cognitive Styles Analysis (Riding, 1991) to determine their positions on the two fundamental cognitive styles, which were indicated by two ratios: the Wholist-Analytic ratio and the Verbal-Imagery ratio. Overall learning behaviour was rated by the pupils' tutors. In addition, attainment in each of 10 subjects was rated by their subject teachers. RESULTS: For overall learning behaviour, there was an interaction between working memory capacity and cognitive style. With the Wholist-Analytic style dimension, memory made a marked difference for Analytics but had little effect for Wholists, and with the Verbal-Imagery dimension Verbalisers were affected but not Imagers. With the school subjects, these differed in terms of their sensitivity to gender, memory and style. CONCLUSION: The results were discussed in terms of differences between the styles in terms of information-processing demands. Practical ways of improving learning performance were also considered.

Adolescent↗
PubMed2005

Antipodal effects of p25 on synaptic plasticity, learning, and memory--too much of a good thing is bad.

Elevated activity of the Cdk5/p25 complex has been implicated in the pathogenesis of Alzheimer's disease. The report by Fischer and colleagues in this issue of Neuron describes a dichotomous role for the activator protein p25 in synaptic plasticity, learning, and memory, whereby transient expression in transgenic mice produces beneficial effects, but prolonged expression is detrimental. This work demonstrates the complexity of Cdk5/p25 in neuronal function and shows that dysregulation of a factor involved in plasticity can cause neurodegeneration.

Animals↗
PubMedDate not supplied

Development of memory and learning skills in school-aged children: a neuropsychological perspective.

While there have been significant theoretical advances in child neuropsychology in recent years, progress in clinical practice has been restricted owing to a lack of well standardized, developmentally appropriate assessment techniques. This paper addresses this issue, with the focus on memory and learning skills. These abilities are targeted because they are frequently impaired following brain damage in childhood, and because they are of central importance to the efficient acquisition of cognitive, educational and social skills throughout childhood. Using a normative sample of 376 children, aged 7.0 to 13.11 years, the paper describes the range of memory and learning skills in childhood, and interprets progress in these skills with reference to neurological and cognitive theory.

Journal Article↗
PubMed2001

Facilitatory effect of substance P on learning and memory in the inhibitory avoidance test for goldfish.

The aim of this study was to investigate if substance P (SP) can improve learning and memory processes in goldfish, using an inhibitory avoidance test. A two-compartment aquarium with a central sliding door was used. The animals were placed in the white compartment, and after 20 s the door was opened. As they entered the dark compartment, a weight was dropped in front of them. This procedure was repeated three times. After training, the animals were injected intraperitoneally with SP or vehicle. Twenty-four hours after training, the animals were tested and their latency was recorded. The group injected with SP showed an increase in the latency on the test day as compared with the vehicle group. These results suggest SP can facilitate memory in goldfish in an inhibitory avoidance test.

Animals↗
PubMed2000

Maternal deprivation affects behaviour from youth to senescence: amplification of individual differences in spatial learning and memory in senescent Brown Norway rats.

Previous studies have shown that deprivation of the infant rat from maternal care has pronounced effects on the stress system during ontogeny. Here we test the hypothesis that 24 h of maternal deprivation at postnatal day 3 will cause persistent changes in behaviour. Spatial learning and memory of male Brown Norway rats deprived as infants were observed in the Morris water maze at 3, 12, 24 and 30-32 months of age (young, adult, aged, senescent). Their nondeprived mother-reared littermates served as controls. (i) With increasing age, water maze performance declined in deprived and nondeprived groups. However, once the task was learned the animals maintained their good performance during retest at later ages. (ii) Maternal deprivation delayed acquisition until adulthood and caused at every age a higher degree of persistent behaviour as judged from the performance of deprived rats' free swim trials and reversal trials. (iii) At senescence the mean performance in the water maze did not differ between the groups. Instead, the individual performance was strikingly different within each group. Senescent deprived rats were either nonimpaired or impaired with only a few animals showing an intermediate performance. Thus, a large group of animals ( approximately 40%) ages successfully as they are resistant to the effect of maternal deprivation. In contrast, the majority of the control animals displayed intermediate performance. Taken together, maternal deprivation has life-long consequences for behaviour and culminates at senescence in amplification of individual differences in learning ability rather than in a generalized deterioration of cognitive functions.

Aging↗
PubMed2003

Cholinergic modulation of learning and memory in the human brain as detected with functional neuroimaging.

The advent of neuroimaging methods such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) has provided investigators with a tool to study neuronal processes involved in cognitive functions in humans. Recent years have seen an increasing amount of studies which mapped higher cognitive functions to specific brain regions. These studies have had a great impact on our understanding of neuroanatomical correlates of learning and memory in the living human brain. Recently, advances were made to go beyond the use of fMRI as a pure cognitive brain mapping device. One of these advances includes the use of psychopharmacological approaches in conjunction with neuroimaging. The paper will introduce the combination of neuroimaging and psychopharmacology as a tool to study neurochemical modulation of human brain function. A review of imaging studies using cholinergic challenges in the context of explicit and implicit learning and memory paradigms is provided which show that cholinergic neurotransmission modulates task-related activity in sensory and frontal cortical brain areas.

Acetylcholine↗
PubMed1990

Learning and memory impairment in rats fed a high saturated fat diet.

At the age of 1 month, three separate groups of Long-Evans rats were placed on 20% (w/w) fat (40% of calories) diets high in either saturated fatty acids (lard-based) or polyunsaturated fatty acids (soybean oil-based) or standard laboratory chow (Purina, 4.5% (w/w) fat). After 3 months, all rats were administered three tests of learning and memory--Olton's radial arm maze, a variable-interval delayed alternation task, and the Hebb-Williams maze series. The lard-fed group was impaired on all tests. The soybean oil-fed group was slightly impaired on some measures, relative to the chow-fed group, but consistently performed better than the lard-fed group. The results indicate that a diet high in saturated fatty acids can impair a wide range of learning and memory functions and are in line with biochemical and physiological evidence showing widespread effects of such diets on brain function.

Animals↗
PubMed2000

A revised spatial serial learning and memory procedure using Corsi's Block-tapping apparatus.

The purpose of this study was to use Corsi's Block Tapping Test as a spatial analog of Benton's Serial Digit Learning Test, using the cognitive neuroscience approach utilized in the California Verbal Learning Test. 60 normal participants, ages 19-52 years, were included and administered an 8-block sequence for 9 trials or until they recalled the entire sequence for 3 consecutive errorless trials. The score was the number of blocks tapped in the correct serial order. An interference trial was administered. Following a 10-min. delay, free recall of the original sequence, cued recall, and recognition measures were obtained. Retroactive interference was significant, but no proactive interference emerged. Scores showed a strong primacy effect. Most participants who learned the sequence to the criterion of three successive errorless trials recalled the sequence after the 10-min. delay. Scores on the cued recall and recognition trials tended to support their validity as less demanding retrieval tasks. The use of this spatial learning and memory procedure allows finer discriminations among nonverbal memory deficits and may facilitate direct comparisons with scores on verbal memory tasks such as Serial Digit Learning and the California Verbal Learning Test.

Adult↗
PubMed2003

[Effect of adenosine A1 receptor antagonist on learning and memory and analysis of its mechanism].

AIM: To study the effect of blocking adenosine A1 receptors on learning and memory and the relation with cholinergic and aminoacidergic nerve. METHODS: Using step through test, spectrophotometry and HPLC method, the effect of selective adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 0.3, 0.15, 0.075, 0.03, 0.015 microgram, icv) on memory impairment by scopolamine (Scop, 3 mg.kg-1 i.p.) or 2-amino-5-phosphonovaleric (AP5, 2.5 ng, icv), acetylcholinesterase (AChE) activity and aminoacid level in brain of mice was studied. RESULTS: DPCPX was shown to significantly improve scopolamine-induced memory impairment, but not AP5-induced. The activity of AChE in mouse brain was significantly inhibited by large doses of DPCPX in vitro and in vivo test. DPCPX(0.3 microgram, icv) was shown to significantly increase the content of glutamate and aspartic acid in brain of mice. DPCPX (0.3, 0.15 microgram, icv) significantly decrease GABA and increase Glu/GABA in brain of mice. CONCLUSION: The selective adenosine A1 receptor antagonist DPCPX was shown to significantly improve scopolamine but not AP5-induced memory impairment. Large doses of DPCPX was shown to influence the AChE activity and the changes in aminoacid level in brain, especially increase Glu/GABA.

2-Amino-5-phosphonovalerate↗
PubMed1995

[The neural basis of learning and memory declines in aged rats].

The synapses, AChE fibers, synaptophysin (SYP), parvalbumin (PV)-containing neurons, synaptosomal Ca2+ concentration and membrane fluidity were studied quantitatively in the brain tissues of young and aged memory-nonimpaired and aged memory-impaired rats according to their memory abilities in the Morris water maze. The results indicated that statistically significant decreases were found in SYP content, the density of synapses, AChE fibers, PV positive neurons and synaptosomal membrane fluidity while an increase was found in [Ca2+]i of neocortex and hippocampal formation in the aged memory-impaired rats as compared with the young and aged memory-nonimpaired rats. But there were no significant differences of these indexes between the young rats and the aged memory-nonimpaired ones. The study suggested that the abnormality of these indexes was closely correlated with the decline of learning and memory in aged rats.

Aging↗
PubMed2004

Sleep-dependent learning and memory consolidation.

While the functions of sleep remain largely unknown, one of the most exciting and contentious hypotheses is that sleep contributes importantly to memory. A large number of studies offer a substantive body of evidence supporting this role of sleep in what is becoming known as sleep-dependent memory processing. This review will provide evidence of sleep-dependent memory consolidation and sleep-dependent brain plasticity and is divided into five sections: (1) an overview of sleep stages, memory categories, and the distinct stages of memory development; (2) a review of the specific relationships between sleep and memory, both in humans and animals; (3) a survey of evidence describing sleep-dependent brain plasticity, including human brain imaging studies as well as animal studies of cellular neurophysiology and molecular biology. We close (4) with a consideration of unanswered questions as well as existing arguments against the role of sleep in learning and memory and (5) a concluding summary.

Animals↗
PubMed2004

The brain angiotensin system and extracellular matrix molecules in neural plasticity, learning, and memory.

The brain renin-angiotensin system (RAS) has long been known to regulate several classic physiologies including blood pressure, sodium and water balance, cyclicity of reproductive hormones and sexual behaviors, and pituitary gland hormones. These physiologies are thought to be under the control of the angiotensin II (AngII)/AT1 receptor subtype system. The AT2 receptor subtype is expressed during fetal development and is less abundant in the adult. This receptor appears to oppose growth responses facilitated by the AT1 receptor, as well as growth factor receptors. Recent evidence points to an important contribution by the brain RAS to non-classic physiologies mediated by the newly discovered angiotensin IV (AngIV)/AT4 receptor subtype system. These physiologies include the regulation of blood flow, modulation of exploratory behavior, and a facilitory role in learning and memory acquisition. This system appears to interact with brain matrix metalloproteinases in order to modify extracellular matrix molecules thus permitting the synaptic remodeling critical to the neural plasticity presumed to underlie memory consolidation, reconsolidation, and retrieval. There is support for an inhibitory influence by AngII activation of the AT1 subtype, and a facilitory role by AngIV activation of the AT4 subtype, on neuronal firing rate, long-term potentiation, associative and spatial learning. The discovery of the AT4 receptor subtype, and its facilitory influence upon learning and memory, suggest an important role for the brain RAS in normal cognitive processing and perhaps in the treatment of dysfunctional memory disease states.

Animals↗