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At least 1,063 records · Page 59Linked to original sources
PubMed1984

Prenatal exposure to carbon monoxide: learning and memory deficits.

Exposing pregnant rats to carbon monoxide (150 parts per million) produced only minor reductions in the birth weights of the pups and gave no evidence of overt teratogenesis. However, behavioral evaluation of learning and memory processes in a two-way avoidance task suggested a functional deficit in the central nervous system of the exposed offspring. Multiple dependent measures and specific control groups confirmed that this deficit was independent of nonassociative or motivational alterations.

Animals↗
PubMed2004

Impairment of verbal memory and learning in antipsychotic-naïve patients with first-episode schizophrenia.

BACKGROUND: Verbal memory deficits are of interest in schizophrenia because of the potential relationship to functional and anatomic mesial temporal lobe pathology in this disorder. The goal of this study was to characterize the nature of verbal memory impairments in antipsychotic-naïve schizophrenic patients early in the course of illness. METHODS: Neuroleptic-naïve patients with schizophrenia (n=62) and healthy individuals (n=67), matched on IQ, age, sex, and parental socioeconomic status, were administered the California Verbal Learning Test (CVLT). RESULTS: Schizophrenia participants performed significantly worse than healthy individuals on measures of verbal learning, short- and long-term memory, and immediate attention. Deficits in recall were related to reduced use of organizational strategies to facilitate verbal encoding and retrieval. No group differences were found in rate of forgetting or susceptibility to proactive or retroactive interference. Memory deficits had minimal relation to positive or negative symptom severity. CONCLUSIONS: Schizophrenia is characterized by significant verbal memory dysfunction early in the course of illness prior to treatment with antipsychotic medications. Deficits in consistency of learning over several trials, as well as a strong relationship between semantic organizational strategies and reduced learning capacity, implicate prefrontal dysfunction as a contributor to verbal memory deficits in schizophrenia.

Adult↗
PubMedDate not supplied

The effect of vasopressin analog: [d(CH2)(1)5,Tyr(Me)2,delta 3Pro7]AVP on learning and memory processes in rats with experimental amnesia.

We investigated the effect of a single 2 micrograms dose of a vasopressin (AVP) analog, [d(CH2)(1)5,Tyr(Me)2,delta 3Pro7]AVP on processes of retrieval, consolidation and acquisition of conditioned reflexes in rats with experimentally induced amnesia. The investigated amnesia models were: long term ethanol intoxication, electroconvulsive shocks (ECS), and hypoxia. They all profoundly impaired the learning and memory processes in all tests used. The AVP analog-[d(CH2)(1)5,Tyr(Me)2,delta 3Pro7]AVP facilitated retrieval of passive avoidance in all amnesia models. It improved consolidation of active avoidance of rats previously treated with alcohol, but did not affect the acquisition of active avoidance. [d(CH2)(1)5,Tyr(Me)2,delta 3Pro7]AVP lack antidiuretic properties.

Alcoholism↗
PubMed2006

The role of acetylcholine in learning and memory.

Pharmacological data clearly indicate that both muscarinic and nicotinic acetylcholine receptors have a role in the encoding of new memories. Localized lesions and antagonist infusions demonstrate the anatomical locus of these cholinergic effects, and computational modeling links the function of cholinergic modulation to specific cellular effects within these regions. Acetylcholine has been shown to increase the strength of afferent input relative to feedback, to contribute to theta rhythm oscillations, activate intrinsic mechanisms for persistent spiking, and increase the modification of synapses. These effects might enhance different types of encoding in different cortical structures. In particular, the effects in entorhinal and perirhinal cortex and hippocampus might be important for encoding new episodic memories.

Acetylcholine↗
PubMed2004

Effects of NMDA receptor antagonists on olfactory learning and memory in the honeybee (Apis mellifera).

In contrast to vertebrates the involvement of glutamate and N-methyl-D-aspartate (NMDA) receptors in brain functions in insects is both poorly understood and somewhat controversial. Here, we have examined the behavioural effects of two noncompetitive NMDA receptor antagonists, memantine (low affinity) and MK-801 (high affinity), on learning and memory in honeybees (Apis mellifera) using the olfactory conditioning of the proboscis extension reflex (PER). We induced memory deficit by injecting harnessed individuals with a glutamate transporter inhibitor, L-trans-2,4-PDC (L-trans-2,4-pyrrolidine dicarboxylate), that impairs long-term (24 h), but not short-term (1 h), memory in honeybees. We show that L-trans-2,4-PDC-induced amnesia is 'rescued' by memantine injected either before training, or before testing, suggesting that memantine restores memory recall rather than memory formation or storage. When injected alone memantine has a mild facilitating effect on memory. The effects of MK-801 are similar to those of L-trans-2,4-PDC. Both pretraining and pretesting injections lead to an impairment of long-term (24 h) memory, but have no effect on short-term (1 h) memory of an olfactory task. The implications of our results for memory processes in the honeybee are discussed.

Animals↗
PubMed1984

Cyclic GABA-GABOB analogues. IV. Activity on learning and memory.

A number of N-substituted 4-hydroxy-, 4-acyloxy- and 4-alkoxy-2-pyrrolidinones were examined by a screening method predictive of their activity on cognitive processes. The 1-aminocarbonylmethyl-substituted compounds showed a favorable effect on learning and memory, and among them the most active was the 4-hydroxy derivative, oxiracetam, which had a potency considerably higher than piracetam, used for comparison purposes.

Amnesia↗
PubMed1994

Memory and learning strategies in patients with Parkinson's disease.

Parkinson's disease patients (PD) do not differ from control subjects (CS) when they have to execute a problem solving task in which external cues for solving the problem are given. However, when PD have to solve a problem by means of an internally generated strategy, they show a serious decrease in performance. We hypothesised that this distinction may also apply to the way PD and CS organize recall. In order to test our hypothesis the California Verbal Learning Test (CVLT) was administered to 59 PD and 30 CS. The test consists of five learning trials using a 16-word target list, composed of four items from each of four semantic categories. The fact that the word list was built on this implicit organization was not divulged in advance. The sequence in which the words were read is fixed; each subsequent word belongs to a category being different from the category to which the preceding word belongs. The organization in recall according to the semantic categories is considered to be the result of an unprompted, internally generated strategy. Recall according to the sequence in which the words are read by the experimenter, is viewed as an externally offered strategy. The results prove to be in line with our hypothesis: unlike CS who appeared to rely mainly and increasingly on an internally generated semantic organization, PD showed evidence of gradually adhering more to the externally imposed serial sequence.

Aged↗
PubMed2006

[Effect of long-term intake of Y3+ in drinking water on learning-memeory functions and growth-development of rats].

OBJECTIVE: The aim of this paper was to learn the effect of long-term intake of Y3+ in drinking water on learning-memory function and growth-development of rats. METHODS: The rats were fed with water dissolved different level Y3+ (0, 0.534, 53.4, 5340 mg/L) for 6 months, pregnant rate, survive rate, bear rate, variety in weight were calculated, the learning-memory function was observed by step-down test. RESULTS: The results showed that a significantly decrease in electric shock period and an increase in incubation period were observed for the low dose group, in contrast, a significantly increase in electric shock period and error times, and an decreases in weight and survive rate were observed for the high dose group. CONCLUSION: Y3+ in 0.534 mg/L might improve the function of learning and memory in rats, and that Y3+ in 5340mg/L could restrain both the function of learning-memory functions and growth-development in rats.

Animals↗
PubMed2004

Combination treatment of neonatal rats with hypoxia-ischemia and endotoxin induces long-lasting memory and learning impairment that is associated with extended cerebral damage.

OBJECTIVE: We assessed the long-term effects of perinatal hypoxia-ischemia and endotoxin on attention and short- and long-term memory in neonatal rats with the use of behavioral tasks and brain histologic results. STUDY DESIGN: Four hours after injections of lipopolysaccharide (1 mg/kg, intraperitoneally) or saline solution, 7-day-old Wistar rat pups were subjected to unilateral hypoxia-ischemia for 1 hour. We studied 4 groups: controls (n = 43 rats), lipopolysaccharide alone (n = 12 rats), hypoxia-ischemia alone (n = 29 rats), and combined lipopolysaccharide + hypoxia-ischemia treatment (n = 34 rats). Seven to 16 weeks after the treatment, we measured attention with a choice reaction time task, short-term memory with an 8-arm radial maze task, and long-term memory with a water maze task. At 19 weeks of age, the brain was removed, fixed, and sectioned coronally; and the volume of each part was measured. RESULTS: A loss of volume in the hippocampus was observed in the lipopolysaccharide, hypoxia-ischemia, and lipopolysaccharide + hypoxia-ischemia groups; a loss of striatum was observed in the hypoxia-ischemia and lipopolysaccharide + hypoxia-ischemia groups, but loss of cortex was observed only in the lipopolysaccharide + hypoxia-ischemia group. The lipopolysaccharide, hypoxia-ischemia, and lipopolysaccharide + hypoxia-ischemia groups showed significantly poorer performance (attention deficit) than controls in the choice reaction time task. Correct choices decreased, and error increased in the lipopolysaccharide + hypoxia-ischemia group compared with the other groups in the radial maze task, which shows short-term memory impairment. Swimming distance was significantly greater in the hypoxia-ischemia and lipopolysaccharide + hypoxia-ischemia groups than in the other 2 groups in the water maze test, which shows long-term memory impairment. CONCLUSION: Combined lipopolysaccharide and hypoxia-ischemia treatment synergistically induced short-term memory impairment that is associated with loss of cortical volume.

Analysis of Variance↗
PubMed1999

Post-trial administration of H1 histamine receptor blocker improves appetitive reversal learning and memory in goldfish, Carassius auratus.

Based on the hypothesis that neuronal histamine exerts an inhibitory influence on learning and reinforcement, goldfish were tested for post-trial effects of the H1 receptor blocker chlorpheniramine (CPA) on learning the location of a food source in one of two compartments, one black the other white, with a feeder located in each compartment. Testing was carried out over 6 days. On the training day a food pellet was placed into the feeder of one of the compartments. After consumption of the food the fish were injected i.p. with either vehicle or CPA either immediately after training or 3 h later. Twenty-four-hours later, food was placed in the same compartment and the time to begin feeding was recorded. On the next day the location of the food pellet was reversed, and testing was continued for 4 days. On the first test day the time to begin feeding was significantly longer for the vehicle injected fish as compared with those injected with CPA. The vehicle group also took longer to begin feeding than the CPA group on the first reversal test day. The results of the 3-h delay groups indicated no significant differences between vehicle and drug for any experimental session. These results suggest that post-trial blockade of the H1 histamine receptor can affect appetitive learning in goldfish either by improving long-term memory consolidation and/or by the additive reinforcing effects of CPA (known from previous studies) on behavior.

Animals↗
PubMed2000

The effect of electroconvulsive therapy (ECT) on implicit memory: skill learning and perceptual priming in patients with major depression.

While explicit memory in amnesics is impaired, their implicit memory remains preserved. Memory impairment is one of the side effects of electroconvulsive therapy (ECT). ECT patients are expected to show impairment on explicit but not implicit tasks. The present study examined 17 normal controls and 17 patients with severe major depressive disorder who underwent right unilateral ECT. Patients were tested in three sessions: 24-48 hours prior to, 24-48 hours following the first ECT, and 24-48 hours following the eighth ECT. The controls were tested in three sessions, at time intervals that paralleled those of the patients. Implicit memory was tested by the perceptual priming task - Partial Picture-Identification (PPI). The skill learning task used entailed solving the Tower of Hanoi puzzle (TOHP). Explicit memory was tested by picture recall from the PPI task, verbal recall of information regarding the TOHP, and by the Visual Paired Association (VPA) test. Results showed that explicit questions about the implicit tasks were impaired following ECT treatment. Patients' learning ability, as measured by the VPA task, was only impaired in the first testing session, prior to ECT treatment, reflecting the effect of depression. In addition, groups only differed in the first session on the learning rate of the skill learning task. Perceptual priming was preserved in the patients' group in all sessions, indicating that it is resilient to the effect of depression and ECT. The results are interpreted in terms of the differential effect of depression and ECT on explicit and implicit memory.

Adult↗