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At least 487 records · Page 27Linked to original sources
PubMed2000

[Protective effect of xinxin capsule on learning and memory impairment in mice].

OBJECTIVE: To investigate the effect of Xinxin Capsule on the scopolamine or ethanol induced impairment of learning and memory retention in mice. METHOD: Step-through and Morris Water-maze methods, wer used to the protective effect of Xinxin Capsule(0.4, 0.8, 1.6 g.kg-1, ig, 16 d) on the scopolamine or ethanol induced impairment of learning and memory retention in mice. RESULT: The Capsule(0.8, 1.6 g.kg-1, ig,) can turn over the Scope so as to induce the impairment of learning, and the Capsule((0.4, 0.8, 1.6 g.kg-1, ig) can improve the ethanol induced impairment of memory retention in mice. CONCLUSION: Xinxin Capsule helps regain as well as impair the learning and memory retention in mice.

Animals↗
PubMed1999

Effects of nucleotides on learning and memory in a Morris water maze test in normal and basal forebrain-lesioned rats.

The effects of nucleotides on learning and memory were studied in normal and basal forebrain-lesioned rats using a Morris water maze test. Chronic oral administration of a nucleotide mixture (500 mg/kg), containing an equal weight of the disodium salts of adenosine 5'-monophosphate, guanosine 5'-monophosphate, inosine 5'-monophosphate, cytidine 5'-monophosphate, and uridine 5'-monophosphate facilitated learning acquisition in normal rats. In basal forebrain-lesioned rats, administration of the nucleotide mixture showed a tendency to improve learning acquisition and memory retrieval. In the biochemical studies, no significant changes were observed in brain choline and acetylcholine levels by treatment with the nucleotide mixture at the doses tested in both normal and basal forebrain-lesioned rats. The nucleotides did not affect the monoaminergic systems in normal rats, but did cause some changes in these systems in basal forebrain-lesioned rats. The present studies indicate that nucleotides ameliorate learning and memory processes in normal rats, but not in basal forebrain-lesioned rats, and they also modulate the activity of the central monoaminergic systems under certain conditions.

Acetylcholine↗
PubMed1987

Effects of extract from Rhapontcum carthamoides (Willd) Iljin (Leuzea) on learning and memory in rats.

The effects of extract from Rhaponticum carthamoides (Willd) Ijin (Leuzea) on the processes of learning and memory in rats were investigated. R. carthamoides was administered orally in doses of 0.25, 0.5 and 2.5 g/kg body weight for 10 days prior to the training session. Using the maze-training method of active avoidance with punitive reinforcement, R. carthamoides improved the learning and memory indices to one degree or another depending on the dose applied. Using the "staircase-maze" method of training with food reinforcement, the low dose of R. carthamoides had no effect, while the high dose deteriorated learning. Using the method of step-through passive avoidance with punitive reinforcement, all three doses of R. carthamoides did not affect substantially the memory indices. R. carthamoides in a dose of 0.5 g/kg, administered orally for 10 days prior to the training, completely eliminated the scopolamine-induced memory impairment.

Animals↗
PubMed2004

Effect of age on the radial arm water maze-a test of spatial learning and memory.

Aged rats show decrements in performance on cognitive tasks that require the use of spatial learning and memory. We used the 8-arm radial water maze (RAWM) to measure spatial learning as a function of age in young (6 months) and old (21 months) male F344 rats. Rats were placed in the RAWM in different start arms with the same goal arm for 3 days (five trials/day); the goal arm was changed on day 4. Old rats demonstrated spatial impairment as evidenced by increased latencies to find the hidden platform on day 4. Old rats made significantly more errors, both reference and working memory errors, than young rats on all days. It is likely that the old rats utilized non-spatial strategies to solve the task, and therefore were impaired in learning a new platform location. The RAWM is a reliable, sensitive, and powerful additional test to assess age-related spatial learning and memory deficits, combining the advantages of the Morris water maze and the radial arm maze while minimizing the disadvantages.

Aging↗
PubMed2003

Effects of subconvulsive electrical stimulation to the hippocampus on emotionality and spatial learning and memory in rats.

OBJECTIVE: To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats. METHODS: One hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n = 42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 mu A with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n = 33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n = 33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze. RESULTS: The stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10.4 +/- 2.3, P < 0.05) and increases in resistance to capture (scale: 2.85 +/- 0.56, P < 0.01). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29 +/- 7) seconds after 15 trials in the water maze, P < 0.05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze. CONCLUSIONS: Following repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.

Animals↗
PubMed2003

Pharmacologically regulated induction of silent mutations (PRISM): combined pharmacological and genetic approaches for learning and memory.

Mouse transgenic and knock-out approaches have made fundamental contributions to our understanding of the molecular and cellular bases of learning and memory. These approaches have successfully identified a large number of molecules with either a central or modulatory role in learning and memory. However, there are limitations associated with first-generation mutant mice, which include, for example, the lack of temporal control over the mutation. Recent technical developments have started to address some of these shortcomings. Here, the authors review a newly developed inducible approach that takes advantage of synergistic interactions between subthreshold genetic and pharmacological manipulations. This approach is easily set up and can be used to study the functional interactions between molecules in signaling pathways.

Animals↗
PubMed1991

Variables affecting long-term memory of learning that a food is inedible in Aplysia.

Long-term memory of learning that a food is inedible was studied in Aplysia. Seven days after a single training session, animals retained significant memory, as measured by a number of parameters. A 2nd experiment demonstrated savings 3 weeks after 2 training sessions. Long-term memory was also found after training procedures were altered to resemble those more likely to occur in nature, such as training for only 10 min or training with ad-lib access to inedible food, with no experimenter intervention. The effects were determined of bilaterally sectioning the esophageal nerves that innervate the gut. Denervation of the gut blocked the ability to learn that food is inedible but did not affect memory after the task had already been learned.

Animals↗
PubMed2001

Does apolipoprotein E influence learning and memory in the nondemented oldest old?

The objective of this study was to analyze the relationship of the apolipoprotein E (apoE) epsilon4 and epsilon2 alleles to learning and memory performances in the nondemented oldest old. Forty-six nondemented persons aged 85 years or over from a randomly selected group of 128 subjects in Vantaa, Finland, were studied. ApoE genotyping was performed using the minisequencing technique. A structured clinical examination and interview were carried out. The test variables studied were learning and memory scores (from the Fuld Object-Memory Evaluation), verbal fluency, and conceptualization (the Similarities subtest of the WAIS-R). We compared apoE-epsilon4 carriers to noncarriers and apoE-epsilon2 carriers to noncarriers. No statistically significant differences were found in any of the test variables. The results failed to confirm the hypotheses that poor cognitive performance is associated with the apoE-epsilon4 allele and good performance with the apoE-epsilon2 allele in the oldest old. This suggests that the apoE alleles do not have a detectable relationship to learning and memory in nondemented very elderly people.

Aged↗
PubMed2001

A new verbal learning and memory test for English- and Spanish-speaking older people.

Word-list verbal learning and memory tests with appropriate normative data can be highly sensitive to cognitive decline, but there are significant limitations of such tests available for use with older Hispanic and non-Hispanic people living in the US. The purpose of this study was to (1) create a new word-list learning and memory test in both English and Spanish and, (2) validate it with respect to sensitivity to cognitive impairment, and (3) develop statistical corrections for the effects of significant demographic variables, including ethnicity, language of administration, age, education, and gender. A community dwelling sample of 801 English- and Spanish-speaking older people was employed. Recall on learning trials and the delayed recall trial of the word-list learning test were strongly related to the Mini-Mental State Examination (MMSE). moderately related to age, and weakly related to gender and education. The relationship of word-list variables and the MMSE did not significantly differ across ethnicity/language groups. Regression coefficients for demographic variables were used in a statistical correction formula to adjust raw word-list scores, and then to develop specific percentile cut-off values.

Aged↗
PubMed2000

[Effects of glutamate and glutamine on learning and memory of rats].

The effects of glutamate (Glu) and glutamine (Gln) on learning and memory of rats and the mechanism involved were examined. Three groups of rats were fed with stock diet (control group), and the diets supplemented with 2% Glu (Glu group) or 2% Gln (Gln group) respectively. Compared with control group, the active avoidance response rats of Gln group in shuttle box test was significantly elevated while the time of passive avoidance response shortened. The contents of brain free amino acids, such as Gln, Glu, aspartic acid and arginine, activity of brain nitric oxide synthase (NOS), Bmax of N-methyl-D-aspartate(NMDA) receptors in hippocampus of Gln group were all increased significantly. Such changes were not observed in Glu group. The results suggested that Gln could improve the learning ability and memory of rats, which might be related to the change of amino acids composition of brain, the synthesis of messenger nitric oxide and the binding capacity of NMDA receptor in hippocampus.

Animals↗
PubMed2003

Cardiac memory and cortical memory: do learning patterns in neural networks impact on cardiac arrhythmias?

Memory is a property of diverse biological systems, including brain and heart. Studies in cortical neuronal networks have identified an increased sensitivity to infrequent (rare) stimulation patterns that can result in their achieving dominance over network firing. This adaptive behavior is applied to the heart in an attempt to explain the ability of pulmonary venous and other ectopic foci to achieve dominance over cardiac rhythm. Developmental changes in determinants of cardiac rhythm are explored as possible determinants of the range of rhythms expressed by the heart. By understanding the mechanisms for these behavior patterns, we may obtain new means for manipulating memory to return dysrhythmic hearts to normal sinus rhythm.

Adaptation, Physiological↗
PubMed1991

Learning and memory function in men with untreated blood pressure elevation.

Learning and memory processes were compared in 20 men with untreated blood pressure elevation and 20 normotensive control subjects matched for age, education, and average alcohol consumption. Subjects were identified from a larger sample of 469 factory workers who had participated in an epidemiologic investigation. Three measures (e.g., Symbol-Digit Learning Test [Ryan & Butters, 1980] and Visual Reproductions-Immediate and Delayed Recall [Wechsler, 1945] ) from a previously administered test battery were chosen for comparison on the basis of statistical power calculations. Results indicate that relative to normotensive control subjects, men with elevated blood pressure performed more poorly on all three tests. These results are independent of other known influences on neuropsychological performance and are likely a consequence of elevated blood pressure.

Adult↗
PubMed2002

Role for brain-derived neurotrophic factor in learning and memory.

In addition to its actions on neuronal survival and differentiation, brain-derived neurotrophic factor (BDNF) has a role in the regulation of synaptic strength. Long-term potentiation, a form of synaptic plasticity, is markedly impaired in BDNF mutant mice, but the changes were restored by the re-expression of BDNF. BDNF also influences the development of patterned connections and the growth and complexity of dendrites in the cerebral cortex. These results suggest a role for BDNF in learning and memory processes, since memory acquisition is considered to involve both short-term changes in electrical properties and long-term structural alterations in synapses. Memory acquisition is associated with an increase in BDNF mRNA and TrkB receptor activation in specific brain areas. Moreover, the pharmacologic and genetic deprivation of BDNF or its receptor TrkB results in severe impairment of learning and memory in mice, rats and chicks. The effect of BDNF on learning and memory may be linked to the modulation of NMDA and non-NMDA receptor functions as well as the expression of synaptic proteins required for exocytosis. Activation of the mitogen-associated protein kinase and/or phosphatidylinositol 3-kinase signaling pathways may be involved in BDNF-dependent learning and memory formation. It is concluded that BDNF/TrkB signaling plays an important role in learning and memory.

Animals↗
PubMed1999

Improvement by nefiracetam of beta-amyloid-(1-42)-induced learning and memory impairments in rats.

1. We have previously demonstrated that continuous i.c.v. infusion of amyloid beta-peptide (A beta), the major constituent of senile plaques in the brains of patients with Alzheimer's disease, results in learning and memory deficits in rats. 2. In the present study, we investigated the effects of nefiracetam [N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, DM-9384] on A beta-(1-42)-induced learning and memory deficits in rats. 3. In the A beta-(1-42)-infused rats, spontaneous alternation behaviour in a Y-maze task, spatial reference and working memory in a water maze task, and retention of passive avoidance learning were significantly impaired as compared with A beta-(40-1)-infused control rats. 4. Nefiracetam, at a dose range of 1-10 mg kg(-1), improved learning and memory deficits in the A beta-(1-42)-infused rats when it was administered p.o. 1 h before the behavioural tests. 5. Nefiracetam at a dose of 3 mg kg(-1) p.o. increased the activity of choline acetyltransferase in the hippocampus of A beta-(1-42)-infused rats. 6. Nefiracetam increased dopamine turnover in the cerebral cortex and striatum of A beta-(1-42)-infused rats, but failed to affect the noradrenaline, serotonin and 5-hydroxyindoleacetic acid content. 7. These results suggest that nefiracetam may be useful for the treatment of patients with Alzheimer's disease.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Chronic administration of the Ca(2+) channel blocker amlodipine facilitates learning and memory in mice.

Acute administration of the Ca(2+) channel antagonist amlodipine has been shown to facilitate memory for several types of learning in adult animals and to improve retention in aging mice. This study reports three experiments investigating the effect of chronic amlodipine treatment on retention in mice. In the first experiment, groups of mice were treated with either amlodipine or vehicle once a day for 14 days prior to training on a spatial discrimination task. Immediately after training, animals were given a single dose of amlodipine or the vehicle and tested for retention 24 h later. Both groups showed facilitated retention, thereby demonstrating that chronic amlodipine treatment did not produce desensitization to the facilitating effects of a post training treatment. In the second experiment, chronic treatments were administered once daily for 14 days beginning 24 h after training on one-way active avoidance and retention was tested on day 15. Results showed that chronic amlodipine attenuated spontaneous forgetting, but surprisingly, a similar enhancement could be achieved by a single treatment administered 1 day after training. In the third experiment, amlodipine was given either before or immediately after 10 daily training sessions in the one-way active avoidance task. Results showed that chronic treatment accelerated rate of learning. These findings confirm the memory facilitating properties of amlodipine under conditions of chronic drug administration.

Amlodipine↗