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PubMed2004

[Effect of radix Rehmanniae preparata on the expression of c-fos and NGF in hippocampi and learning and memory in rats with damaged thalamic arcuate nucleus].

OBJECTIVE: To study the effect of Radix Rehmanniae Preparata (RRP) on improving the function of learning and memory. METHOD: With injured thalamic arcuate nucleus rats induced by MSG, the improving function of RRP on learning and memory was observed by step down task and Morris water maze task, and the expression of c-fos and NGF in hippocampi was observed by immunohistochemical means. RESULT: RRP could decrease the times of mistakes and prolong the incubation period in step down task, shorten the incubation period of seeking the platform, and improve the rate through the platform position in Morris water maze task. RRP could also increase the expression of hippocampal NGF, c-fos. CONCLUSION: RRP could improve the function of learning and memory of MSG rats, and its mechanism may by related with the increase of the expression of hippocampal c-fos and NGF.

Animals↗
PubMed2005

[Effects of lidocaine on impairment of learning and memory function and cholinergic system caused by cerebral microsphere embolism in rats].

OBJECTIVE: To investigate the effects of lidocaine on impairment of learning and memory function and cholinergic system caused by cerebral microsphere embolism in rats. METHODS: Healthy male Wister rats were randomly divided into the following groups. (1) Control group. (2) 600 microsphere group and 900 microsphere group, in which 600 or 900 microspheres were injected into the right internal carotid artery, respectively. (3) 600 treatment group and 900 treatment group, in which 600 or 900 microspheres were injected into the right internal carotid artery, respectively, and lidocaine was given. Water maze tasks were tested for 5 consecutive days from the 7th postoperative day. The rats were then decapitated and regions of cerebral cortex, hippocampus, and striatum were selected. The activities of choline acetyltransferase and cholinesterase and the binding activity of muscarinic receptor were determined. RESULTS: (1) The latency periods were significantly longer in the 900 microsphere group than in the control group and in the 600 microsphere group. (2) The percentages of effective search strategy were significantly lower in the 600 and 900 microsphere groups than in the control group. They were significantly higher in the 600 and 900 treatment groups than in the corresponding microsphere groups. (3) The activities of choline acetyltransferase of cerebral cortex were significantly lower in the 900 microsphere and two treatment groups than in the control group. They were also significantly lower in the 600 and 900 treatment groups than in the corresponding microsphere groups. Those of striatum were all significantly lower in the microsphere and treatment groups than in the control group. (4) The activities of cholinesterase of cerebral cortex were significantly lower in the 900 microsphere group than in the control and 600 microsphere groups. They were significantly higher in the 900 treatment group than in the 900 microsphere group. Those of hippocampus were all significantly lower in the microsphere and treatment groups than in the control group. (5) The binding activities of muscarinic receptor of cerebral cortex were significantly lower in the 900 microsphere and two treatment groups than in the control group. They were also significantly lower in the two treatment groups than in the corresponding microsphere groups. Those of hippocampus and striatum were all significantly lower in the microsphere and treatment groups then in the control group. They were also significantly lower in the 600 or 900 treatment group than in the corresponding microsphere group. CONCLUSION: Cerebral microsphere embolism caused significant and quantity-dependent impairment of learning and memory function and cholinergic system in rats. Lidocaine alleviated learning and memory dysfunction caused by cerebral microsphere embolism, but further inhibited the parameters of central cholinergic system.

Animals↗
PubMed2003

A learning and memory area in the octopus brain manifests a vertebrate-like long-term potentiation.

Cellular mechanisms underlying learning and memory were investigated in the octopus using a brain slice preparation of the vertical lobe, an area of the octopus brain involved in learning and memory. Field potential recordings revealed long-term potentiation (LTP) of glutamatergic synaptic field potentials similar to that in vertebrates. These findings suggest that convergent evolution has led to the selection of similar activity-dependent synaptic processes that mediate complex forms of learning and memory in vertebrates and invertebrates.

Animals↗
PubMed2003

[The improvement of taurine in learning and memory ability of rats exposed to lead].

OBJECTIVE: To investigate the improvement of taurine (Tau) in learning and memory ability of rats exposed to lead. METHODS: Forty Wistar rats were randomly divided into control group: treated with distilled water; lead group: treated with lead acetate (40 mg.kg(-1).d(-1)); lead-taurine group 1, 2, 3: lead acetate (40 mg.kg(-1).d(-1)) + different concentrations of taurine (100, 400, 800 mg.kg(-1).d(-1)). The ability of learning and memory of rats were measured weekly by spatial water maze test from the 5th to 8th week. At the end of the experiment, the rats were killed, the samples of blood and brain were taken for test. RESULTS: (1) The time of seeking anchorage of lead-Tau 800 mg group in the 6th, 7th, 8th week and that of lead-Tau 400 mg group in the 6th week were significantly lower than that of lead group (P<0.05). (2) Blood lead contents in lead-Tau 100 mg and lead-Tau 400 mg group [(510.9 +/- 57.56) microg/L, (485.40 +/- 98.85) microg/L] were different from those in lead group (P<0.05). (3) The content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), nitric oxide synthase (NOS), acetylcholinesterase (AChE) in brain of lead-Tau 800 mg group and lead-Tau 400 mg group were also different from those in lead group (P<0.05 or P<0.01). The content of GSH and the activity of GSH-Px in lead-Tau 800 mg group were different from those in lead group (P<0.05) as well. CONCLUSION: Taurine could improve learning and memory ability of rats exposed to lead and may play a protective role in brain.

Animals↗
PubMed1988

Learning and memory test performance in alcoholics as a function of monetary incentive.

The performance deficits of alcoholics on tests of learning and memory are typically attributed to cognitive impairment. This study tests an alternative hypothesis that the deficits are due to motivational impairment. A face-name learning and memory test was administered to 30 sober male nonalcoholic and 40 alcoholic subjects in a 2 x 2 [Group (alcoholic, nonalcoholic) x Monetary incentive (incentive, no incentive)] between-subjects design. The monetary incentive was made contingent upon performance. Alcoholics required significantly more trials to learn face-name pairs, and they recalled fewer face-name pairs at the delayed recall. Incentive subjects manifested a trend toward impairment on the trials-to-learn measure. However, there were no significant Group x Incentive interactions in learning or memory, or on a self-report questionnaire of subjective states (e.g., effort expended) experienced during the test. Thus, no evidence was found to support the impaired motivation hypothesis; the cognitive hypothesis remains as the most credible hypothesis to account for the performance deficits of alcoholics.

Adult↗
PubMed2003

[Effect of shu di-huang on the expression of c-fos and NGF in hippocampi and learning and memory of rats damaged thalamic arcuate nucleus].

OBJECTIVE: To study the mechanism of Shu Di-huang in improving the function of learning and memory. METHOD: On the rats model with thalamic arcuate nucleus dameged by MSG, the improving function of Shu Di-huang on learning and memory was observed by step down task and Morris water maze task, and the expression of c-fos and NGF in hippocampi was observed by immunohistochemical means. RESULT: Shu Di-huang could decrease the times of mistakes and prolong the incubation period in step down task, and shorten the incubation period of seeking the platform, and improve the percentage rate through the platform position in Morris water maze task. Shu Di-huang also increase the expression of hippocampal NGF, c-fos. CONCLUSION: Shu Di-huang can improve the function of learning and memory of MSG rats, and its mechanism may be related with the increase of the expression of hippocampal c-fos and NGF.

Animals↗
PubMed2004

Simultaneous depletion of serotonin and catecholamines impairs sustained attention in healthy female subjects without affecting learning and memory.

Monoamine neurotransmitters, serotonin, noradrenaline and dopamine modulate many important cognitive processes such as attention, learning and memory. While the selective effects of serotonin and catecholamine depletion on such processes have been investigated, the effects of simultaneous depletion of these monoamines on cognition remain unclear. This is of particular interest given that multiple neurotransmitter abnormalities have been implicated in many psychiatric disorders. The aim of the current study was to examine the effects of lowered brain monoamine function on cognitive performance, using the technique of amino acid precursor depletion. The study was a double-blind, placebo-controlled design in which 20 healthy female subjects were tested under a combined monoamine depletion condition (CMD) and a balanced control condition (B). Cognitive testing was conducted at baseline and 5 h post-depletion. The CMD condition relative to the B condition resulted in deficits in digit vigilance (accuracy and reaction time), a measure of sustained attention. There were no effects on measures of learning and memory or psychomotor function. These findings suggest that simultaneously depleting the availability of brain serotonin and catecholamines in healthy female subjects selectively impairs sustained attention, without affecting other cognitive domains.

Adolescent↗
PubMed2002

[Effect of tiaoxin recipe on learning and memory related gene expression in hippocampus of senescence accelerated mice].

OBJECTIVE: To study the effect of Tiaoxin Recipe (TXR) on learning and memory related gene expression in hippocampus of senescence accelerated mice (SAM). METHODS: Changes of learning and memory related gene expression, including mineralocorticoid receptor (MR), presenile protein 1 and 2 (PS-1, PS-2), tau, APP, apoE and bcl-2 in hippocampus of SAM were determined by reverse transcription polymerase chain reaction (RT-PCR). The effect of TXR were tested. E2020 was used as the drug for control. RESULTS: Compared with those in the same aged mice, in the 5-month old SAM, levels of gene expression of MR, tau, PS-2 and APP were significantly higher, that of apo-E lower, levels of gene expression PS-1 and bcl-2 were unobviously changed; while in the 12-month old SAM, gene expression of MR and tau were higher, bcl-2 was lower and PS-1, PS-2, apoE and APP were also unobviously changed. Continuously orally taken TXR could correct the abnormality of MR, tau and apoE gene expression in hippocampus of 5-month SAM and that of MR and bcl-2 in 12-month SAM. CONCLUSION: Continuously orally taken of TXR has the effect of regulating and correcting learning and memory related gene expression in hippocampus of 5-month and 12-month SAM.

Aging↗
PubMedDate not supplied

[Hippocampal dimensions, memory and learning during rat ontogenesis].

Injury to the hippocamp disturbs learning processes and short-term memory in 20-, 50- and 110-day rats. In 50-day rats, hippocampectomy results in lesser changes in learning and memory than in 20- and 110-day animals. Anatomo-physiological characteristics of the hippocamp in 20-day rats presumably indicate a particular importance of this structure at early stages of ontogenesis, when the brain cortex is not yet sufficiently mature and its connections with other structures are not completely formed. Non-linear dependence of learning disturbance in rats of varying age after hippocampectomy suggests that in rat hippocampal function undergoes changes during individual development of animals.

Age Factors↗
PubMed2005

BDNF protects against stress-induced impairments in spatial learning and memory and LTP.

The present study investigated whether infusion of brain-derived neurotrophic factor (BDNF) could ameliorate stress-induced impairments in spatial learning and memory as well as hippocampal long-term potentiation (LTP) of rats. Chronic immobilization stress (2 h/day x 7 days) significantly impaired spatial performance in the Morris water maze, elevated plasma corticosterone, and attenuated LTP in hippocampal slices from these animals as compared with normal control subjects. BDNF was infused into the left hippocampus (0.5 mul/h) for 14 days, beginning 7 days before the stress exposure. The BDNF group was protected from the deleterious effects of stress and performed at a level indistinguishable from normal control animals despite the presence of elevated corticosterone. BDNF alone and sham infusions had no effect on performance or LTP. These results demonstrate that spatial learning and memory, and LTP, a candidate neural substrate of learning and memory, are compromised during chronic stress, and may be protected by BDNF administration.

Animals↗
PubMed2005

[Effects of Naomaitai capsule on learning and memory and content of Ach in rat model produced by cerebral ischemia-reperfusion].

OBJECTIVE: To observe the effects of Naomaitai capsule on the learning and memory abilities and the content of acetylcholine(Ach) in the brain tissue of the model rat. METHOD: One vascular dementia(VD) model was produced by occlusion of bilateral common carotid arteries in rats with following steps: ischemia 20 minutes-reperfusion 10 minutes-ischemia 20 minutes. The learning and memory abilities were tested by water maze. The other VD model was formed by 4-vessel occlusion-reperfusion injury in rats. The time of right reflect recovery and the content of Ach in the brain tissue were determined. RESULT: Naomaitai capsule can significantly improve the learning and memory abilities of the dementia rats( P < 0.05, P < 0.01), increase the content of Ach (P < 0.05, P < 0.01) and reduce the time of right reflect recovery(P < 0.01). CONCLUSION: Naomaitai capsule can improve the learning and memory abilities by increasing the content of Ach of the VD rats.

Acetylcholine↗
PubMed1995

Age-related decrease of plasma testosterone in SAMP8 mice: replacement improves age-related impairment of learning and memory.

Corticosterone increases with aging but pregnenolone, dehydroepiandrosterone, and testosterone decrease. The marked decrease in hormones that occurs with aging may contribute to the age-related deficit in learning and memory. Administration of these hormones after training was found to improve long-term memory processing in normal young mice. SAMP8 (P8) mice show an age-related loss of learning and memory for a variety of tasks whereas age-matched control mice of the closely related SAMR1 (R1) strain do not. In this study, we found an age-related decrease in serum testosterone levels of 71% between P8 mice 4 and 12 months of age, but only a 26% decrease between R1 mice of the same ages. The difference between the P8 mice was significant (p < 0.01) and the difference between the R1 mice was not. The decrease in testosterone in 12-month-old P8 mice was not accompanied by gross morphological change in the testes. A SC testosterone implant, sufficient to increase plasma testosterone levels to 414 +/- 25 ng/dl, alleviated impaired learning and memory of a foot shock avoidance task in P8 mice. Castration of 4-month-old P8 mice did not produce a deterioration in learning and memory, indicating that low levels of testosterone per se are not responsible for the impairment seen in 12-month-old P8 mice. This suggests that impaired cognitive functioning of the older P8 mice was due to an interaction of aging and reduced testosterone levels.

Aging↗
PubMed2000

Human immunodeficiency virus-1 coat protein gp120 impairs contextual fear conditioning: a potential role in AIDS related learning and memory impairments.

Many AIDS patients suffer from cognitive impairments including deficits in learning and memory. The Human Immunodeficiency Virus-1 (HIV-1) envelope glycoprotein gp120 is one possible mediator of these impairments. This is because gp120 activates brain microglial cells and astrocytes, and in vivo activation of glia leads to the release of the proinflammatory cytokine interleukin-1 beta (IL-1beta). gp120 induced IL-1beta release could be involved in producing memory impairments associated with AIDS because central IL-1beta activity adversely affects cognitive function. The reported experiments evaluated the effects of i.c.v. gp120 administration and subsequent IL-1beta activity on learning and memory processes in the rat. Intracerebroventricular gp120 produced memory impairments on hippocampally dependent contextual fear conditioning, but not hippocampally independent auditory-cue fear conditioning following post-conditioning gp120 administration. Central gp120 administration also caused increases in IL-1beta protein levels in the hippocampus and frontal cortex but not in the hypothalamus. gp120 induced memory impairments were blocked by 2 different IL-1 antagonists, alpha melanocyte stimulating hormone (alphaMSH) and interleukin-1 receptor antagonist (IL-1ra). Finally, heat denaturation of the tertiary structure of gp120 abolished its effects on fear conditioning, suggesting that gp120 impairs contextual fear conditioning by binding to its receptors on glia.

AIDS Dementia Complex↗
PubMed1992

latheo, a new gene involved in associative learning and memory in Drosophila melanogaster, identified from P element mutagenesis.

Genetic dissection of learning and memory in Drosophila has been limited by the existence of ethyl methanesulfonate (EMS)-induced mutations in only a small number of X-linked genes. To remedy this shortcoming, we have begun a P element mutagenesis to screen for autosomal mutations that disrupt associative learning and/or memory. The generation of "P-tagged" mutant alleles will expedite molecular cloning of these new genes. Here, we describe a behavior-genetic characterization of latheoP1, a recessive, hypomorphic mutation of an essential gene. latheoP1 flies perform poorly in olfactory avoidance conditioning experiments. This performance deficit could not be attributed to abnormal olfactory acuity or shock reactivity-two task-relevant "peripheral" behaviors which are used during classical conditioning. Thus, the latheoP1 mutation appears to affect learning/memory specifically. Consistent with chromosomal in situ localization of the P element insertion, deficiencies of the 49F region of the second chromosome failed to complement the behavioral effect of the latheoP1 mutation. Further complementation analyses between latheoP1 and lethal alleles, produced by excision of the latheoP1 insert or by EMS or gamma-rays, in the 49F region mapped the latheo mutation to one vital complementation group. Flies heterozygous for latheoP1 and one of two EMS lethal alleles or one lethal excision allele also show the behavioral deficits, thereby demonstrating that the behavioral and lethal phenotypes co-map to the same locus.

Animals↗
PubMed2004

Dysexecutive syndrome following anterior thalamic ischemia in the dominant hemisphere.

In the article, we describe a rare case: a 52-year-old male patient with an isolated lesion of the anterior thalamic nuclei in the dominant hemisphere due to an ischemic stroke. The patient's syndrome of disordered verbal fluency, working memory, learning and executive functions is seen as a part of a lesion in the dorsolateral complex circuit. During the following 6 months, we observed significant improvement in visual learning, recent memory and categorisation of subjects, while verbal learning and visuospatial planning remained insufficient. In this context, the preservation of thalamic structures in different types of cognitive deterioration is discussed.

Affect↗
PubMed1998

Role of vasopressin in learning and memory in the hippocampus.

The involvement of arginine8-vasopressin (VP) in learning and memory in the hippocampus is examined in mice using a discriminative learning task. Bilateral dorsal hippocampal lesion blocks the enhancing effect of intracerebroventricular (i.c.v.) injection of VP on retrieval and relearning processes. An additional study showed that immunoneutralization of dorsal hippocampal endogenous VP inhibited the facilitating effect of i.c.v. injection of VP, suggesting that hippocampus is essential for the expression of VP's behavioral effects. Using in situ microinjection, a greater sensitivity of the ventral part of the hippocampus to the memory enhancing effects of VP has been reported. This effect is mediated by vasopressin V1 type receptors and oxytocin receptors. Then, we examined the effects on behavior of VP applied to the ventral hippocampus, in relation to the time of treatment during learning. When the animals have no previous information about the task to learn, a deleterious effect of VP appears (pre-first session treatment). Regarding memory consolidation, the effects of VP may depend upon the previous level of performance acquired by the animals since, when injected after the first learning session, the peptide slightly delayed performance, whereas when the injection took place after the second learning session, it enhanced learning. Concerning memory retrieval, the effects of VP depend on the quality of the previously stored information. The fact that VP did not generate the same behavioral effects when the treatment was performed at the beginning or in the middle of the learning processes, suggests that mnemonic context is an important factor in understanding the effect of VP on memory in the ventral hippocampus. Finally, the role of hippocampal adrenergic receptors in the enhancing VP effects on memory retrieval has been examined. The facilitatory effects of VP seem to depend upon the functional state of both alpha- and beta-adrenergic receptors, but further studies will be necessary to clarify the role played by each receptor type in retrieval processes, and to determine the relationships that might exist between them.

Animals↗
PubMed1993

Influence of histamine depletion on learning and memory recollection in rats.

To clarify the role of endogenous histamine in learning and memory, the effect of alpha-fluoromethylhistidine on active avoidance response in rats was studied. alpha-Fluoromethylhistidine (20-100 mg/kg or 10-50 micrograms) significantly (P < 0.05 or P < 0.01) prolonged the response latency in active avoidance response when administered by either intraperitoneal or intracerebroventricular injection. These effects were dose-related and long lasting. A prolongation of the response latency induced by an intraperitoneal injection of alpha-fluoromethylhistidine (100 mg/kg) was antagonized by intracerebroventricular injection of histamine (10 and 20 ng) in a dose-dependent manner. In addition, the acquisition of this response was retarded by a consecutive intracerebroventricular injection of alpha-fluoromethylhistidine (50 micrograms), whereas histamine (100 ng) facilitated the response acquisition when administered by the same route. Both intraperitoneal (100 mg/kg) and intracerebroventricular injection of alpha-fluoromethylhistidine (50 micrograms) significantly (P < 0.05 or P < 0.01) decreased the brain histamine content, especially in the hippocampus and hypothalamus. When alpha-fluoromethylhistidine (50 micrograms) was injected intracerebroventricularly, there is a high correlation between a prolongation of the response latency and a decrease in histamine content of these brain areas. Based on these findings, it was concluded that an intimate relation may exist between a prolongation of response latency in the active avoidance response and a decrease in the brain histamine content; endogenous histamine may play an important role in learning and memory recollection in rats.

Animals↗
PubMed2003

[Effects of compound yi-zhi on learning and memory disorder and beta-amyloid protein induced neurotoxicity].

OBJECTIVE: To investigate the effects of Compound Yi-Zhi (CYZ) on learning and memory disorder and beta-amyloid protein induced neurotoxicity. METHODS: Various doses of CYZ were administered to SD rats for 8 days, twice a day. Then scopolamine hydrobrominde intraperitoneal injection was performed on each rat, and the MORRIS water maze test and step-though test were carried out respectively to explore the changes of the rats' learning and memory capacities. Primary rat cortex neurons were cultured in vitro for 7 days, and then serum containing CYZ was added to neurons before or after the addition of beta Amyloid peptide25-35 (A beta 25-35) to observe CYZ's protectiveness on neurotoxicity. MTT assay and test of level of LDH in the culture media were performed to achieve this aim. RESULTS: Compared with control group, in MORRIS water maze test time of finding the platform under the water surface decreased, and in step-though test the latent period rose and the error number got smaller. Moreover, in cultured primary neurons, the dramatic drop of LDH level in culture media and the high OD scores in MTT test indicated that CYZ could effectively resist the neurotoxicity induced by A beta 25-35. CONCLUSION: CYZ presented promising effects on learning and memory dysfunction and A beta-induced neurotoxicity in vitro.

Amyloid beta-Peptides↗