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Results for “Discrimination Learning”

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PubMed1984

Facilitating visual discrimination learning of moderately and severely mentally retarded children through illumination of stimuli.

The effectiveness of illuminating the positive stimulus after a correct response in visual discrimination training of moderately and severely mentally retarded children was investigated. An economical unit for illumination of stimuli was designed for purposes of the present investigation and for possible use in nonspeech communication training of mentally retarded children. In Experiment 1, the illumination of black stimuli on white backgrounds failed to facilitate discrimination learning. In Experiment 2, however, illumination of white stimuli on black backgrounds facilitated discrimination learning. The findings in the second experiment support the use of changes in illumination as an attention-influencing feature of nonspeech communication keyboards for retarded children.

Attention↗

PubMed1975

Genetic analysis of water maze discrimination learning for Mus musculus: polygenes and albinism.

Recombinant inbred strains, their progenitor strains and reciprocal F1 hybrids were given thirty spatial discrimination learning trials in the water maze. The pattern of RI strains in relation to the reciprocal F1 hybrids and the progenitor strains, and differences among strains, suggested that different sets of genes affect the various components of water maze discrimination learning. There was no evidence that the albino gene influenced either inferior or superior performance. Pigmented strains performed as well as, or better than, some albino strains, and albino strain BALB/cBy differed significantly from albino strains CXBG and CXBI. The two reciprocal F1 hybrids differed from blocks 2 and 3 of discrimination trials when swimming time was used a dependent variable. Thus, it appears that performance of the F1 hybrids was influenced by paternal effects, maternal effects, or paternal maternal interactions.

Albinism↗

PubMed1976

Differences in the effects of post-trial chlorpromazine, reserpine, and amphetamine on discrimination learning in rats.

Rats were trained to perform in discrimination learning reinforced by water for 6 days, and were intraperitoneally injected with chlorpromazine, reserpine, or d-amphetamine after each training session. Although chlorpromazine at the dose levels of 0.5 mg/kg or more injected immediately after training impaired learning, the drug did not affect learning when it was injected 60 min after training. Reserpine and amphetamine also impaired learning, but delaying the time intervals between training and injection to 60 min or more had no influence on this learning impairment. Post-trial chlorpromazine and amphetamine had no effect on, but reserpine decreased, motility in the subsequent training session. Chlorpromazine had no effect on water intake in the subsequent session, but reserpine and amphetamine decreased water intake at the dose levels that impaired learning. It was concluded that all three drugs impaired learning, but differed in their effects on learning; chlorpromazine impaired learning by a specific effect on learning itself; reserpine, by a non-specific effect on behavior due to a long acting sedation; and amphetamine, by an effect to decrease the motivation to drink water. The specific effect of chlorpromazine could be related to the hypothesis of "memory trace" synthesis.

Animals↗

PubMed1989

Telencephalic function implicated in food-reinforced color discrimination learning in the goldfish.

The effects of telencephalic ablation on the learning of color discrimination were studied in the goldfish (Carassius auratus) to determine the role of the telencephalon in the learning. The performances of normal and telencephalonless animals were compared in relation to their instrumental training rates. The animals were trained to discriminate between blue and green stimulating patches presented simultaneously. Normal and telencephalonless animals which underwent ten trials per day were unable to discriminate between the stimuli, but animals which underwent thirty trials showed learning. In animals which underwent twenty trials, there was a clear difference between the performances of normal and telencephalonless animals: the normal ones were able to learn, but the telencephalonless ones showed a significantly impaired learning ability. These results suggest that the telencephalon is not essential for the learning, but is supplementary in that it facilitates integration of neural events in extratelencephalic areas that are necessary for the instrumental process involved in color discrimination learning.

Animals↗

PubMed1984

Bar-pressing for water reward: effects of nootropic drugs and peptides on discrimination learning in rats.

Rats maintained on 23-hr water deprivation were first trained to bar-press for continuous water reinforcement and then to discriminate between regularly alternating periods (24 sec) during which time a light signal was either on and each response was reinforced or the light was off and bar-presses were not rewarded. The following drugs were injected s. c. prior to the sessions of discriminative learning: piracetam, 1-(4-Methyl-piperazinocarbonylmethyl)-2-pyrrolidone/hydrogen maleate (VUFB 13763), N alpha-glycyl-glycyl[8-lysine]des-9-glycinamide-vasopressin (DG-Trigly-LVP) and an analog of MIF, EUC-Leu-beta-Ala-NH2 (EUC, 2-oxoimidazolidine-1-carboxylic acid). None of the drugs influenced the total number of bar-pressing (sum of reinforced and non reinforced responses). Piracetam (100 mg.kg-1), VUFB 13763 (40 mg.kg-1) and EUC-Leu-beta-Ala-NH2 (1 mg.kg-1) improved the performance of rats on the discrimination learning task, DG-Trigly-LVP slowed the rate of acquisition.

Animals↗

PubMedDate not supplied

Testing strategies in behavioral teratology: II. Discrimination learning.

Male and female Wistar rats exposed to methylmercury chloride prenatally via drinking water (1.5 and 5.0 mg/l) were tested in a microcomputer-directed learning task (visual discrimination reversal) at the age of two months. Differences were observed between control and high dose group for several parameters, the most obvious being an increase in passiveness and in response latency, as well as a decrease in intertrial interval response rates in the methylmercury group. No effects were seen in the low dose group. Performances of male and female animals were quite similar. However, females showed longer response latencies and passiveness scores were somewhat higher than in males.

Amphetamine↗

PubMed1975

Visual discrimination learning in cats with different early visual experiences.

Simultaneous object discrimination learning in an alimentary situation was strongly impaired in cats deprived from birth of patterned visual experience. The same impairment was observed in cats with experience limited to those objects that were used later in the discrimination task. Some impairment was also present in cats which were reared with opened eyes in the laboratory as compared with normal cats, that spent the early period of life outside of the laboratory. It is concluded that the deprived cats were impaired mainly because of the lack of opportunity during early development to use visual cues in alimentary tasks.

Animals↗

PubMedDate not supplied

Can ACTH analogs support discriminative learning in rats?

Ten rats were trained to discriminate between the stimulus properties of subcutaneously (SC) administered MSH/ACTH4-10 and saline in a two-lever, food-motivated operant task. After 12 weeks of discriminative training with 100 micrograms/kg MSH/ACTH4-10, half the rats received 200 micrograms/kg MSH/ATCH4-10, whereas the other half were administered 400 micrograms/kg, for 6 additional weeks. Subsequently, all rats continued training on 50 micrograms/kg ORG 2766 (SC) and, after 12 weeks of training, were randomly assigned to receive either 100 or 200 micrograms/kg ORG 2766. The results of this extensive 36 week training schedule indicate that only 1 of the 10 rats learned to discriminate the interoceptive cues produced by the ACTH analogs. However, this rat's performance was so sustained and errorless that the possibility exists that it was relatively more sensitive to the effects of MSH/ACTH4-10 and its analogs and that these substances may support discriminative learning in the rat.

Adrenocorticotropic Hormone↗

PubMed1976

Theoretical and methodological considerations on drug discrimination learning.

A method is described which allows the assessment of discriminative stimulus properties of drugs, and the ability of amphetamine (0.16 mg/kg s.c.), chlordiazepoxide (5 mg/kg p.o.), desipramine (5 mg/kg s.c.), and haloperidol (0.02 mg/kg s.c.) to produce a discriminative stimulus complex (DSC) is evidenced. The method is found to yield clear-cut data that are specifically related to drug discrimination learning without being possibly confounded by state dependent effects. In addition, the experimental procedure is designed so as to provide an appropriate measurement of operant response modulating drug effects.

Amphetamine↗

PubMed1985

Visual discrimination learning in mentally handicapped adults: comparative effects of two-choice and multiple-choice training methods on stimulus generalization performance.

The hypothesis that in mentally handicapped subjects a multi-choice discrimination learning method would result in superior generalization performance to the traditional two-choice method was investigated experimentally. Twenty-four mentally handicapped adults matched for age, intelligence and duration of institutionalization were divided into two equal groups and given visual discrimination training using a differential reinforcement, prompt-fading procedure. The groups were allocated separately to a two-choice and four-choice training condition in which the discriminative stimulus was associated with one and three non-discriminative stimuli respectively. Following training, stimulus discrimination performance was compared on a generalization test comprising increasing levels of distraction. The results showed a clear advantage for multi-choice training over two-choice. However, it was found that during generalization testing discriminative performance deteriorated as a function of increasing distraction in both groups, suggesting an underlying selective attention defect. Such a defect may be characteristic of stimulus generalization performance in the mentally retarded. Multi-choice discrimination learning appeared partly to counteract major generalization failure when the ratio of non-discriminative to discriminative stimuli was high.

Adult↗

PubMed1979

Discrimination learning without short-term memory: dissociation of memory processes in pigeons.

Pigeons were trained to perform delayed matching to samples of food and no food when each sample concurrently served as the outcome of a discrimination learning trial which immediately preceded each matching trial. Ambient light presented during the delays after the samples of food or no food severely disrupted matching but had no effect on the rate of discrimination learning.

Animals↗

PubMed1975

Prehatch color stimulation effects on color pecking preferences and color discrimination learning in white leghorn chicks.

Four experiments assessed the effects of stimulating chick embryos with colored light at 2 intensity levels. Both posthatch color pecking preferences (Experiments 1 and 2) and color discrimination learning (Experiments 3 and 4) were unaffected. These results affirm and extend a prior finding of no pre- and posthatch colored light stimulation effect on posthatch color preferences in ducklings. The color pecking preferences found replicated prior findings with chicks. However, they differed from the approach color preferences observed in color discrimination learning.

Animals↗

PubMed1978

Changes in pattern discrimination learning induced by visual deprivation in normal and commissurotomized pigeons.

The effect of monocular (MD), binocular (BD) and alternating monocular (AMD) deprivation on monocular pattern discrimination learning and interocular transfer was investigated in pigeons reared with intact and sectioned supraoptic decussation (DSO). In BD and AMD animals acquisition and interocular transfer of two different pattern discrimination problems remained as good as in the control animals (CO). Monocularly deprived animals (MDE) required significantly more trials to learn the discriminations through the deprived eye, when it was trained first, and interocular transfer from the deprived to the experienced eye was absent. However, if the experienced eye was trained first (MED), learning with the deprived eye was at least as rapid as with the experienced eye. This indicates positive interocular transfer from the experienced to the deprived eye. Interocular transfer of pattern discriminations was completely blocked by section of the DSO in both adults (DSOad) and newly hatched animals (DSOjuv). The elimination of binocular interaction by commissurotomy from the beginning of the postnatal life failed to produce an impaired pattern discrimination learning in monocularly deprived animals.(MD+DSO). The results are discussed in terms of competition between the projections from both eyes in the visual Wulst.

Animals↗

PubMed1992

Naloxone as a stimulus in drug discrimination learning: generalization to other opiate antagonists.

Nonopiate dependent animals were trained to discriminate the opiate antagonist naloxone (1 mg/kg) from distilled water within the conditioned taste aversion baseline of drug discrimination learning. Specifically, rats injected with naloxone prior to a saccharin-LiCl pairing, and with its vehicle prior to saccharin alone, rapidly acquired the drug discrimination, avoiding saccharin following the administration of naloxone and consuming saccharin following its vehicle after only three conditioning trials. Once the discrimination was acquired, generalization tests revealed that the opiate antagonists diprenorphine and naltrexone and the mixed opiate agonist/antagonist nalorphine completely generalized to the naloxone cue at doses of 1.8, 5.6 and 18 mg/kg, respectively. That discriminative control was established with a low dose of naloxone (i.e., 1 mg/kg) and other compounds with opiate antagonist activity generalized to the naloxone cue suggest that the stimulus effects of naloxone were likely mediated through the opiate receptor. Because each of these compounds are reported to bind to the mu receptor (with varying affinities and varying degrees of selectivity), the stimulus properties of naloxone are likely mediated at this specific receptor subtype.

Animals↗

PubMed1977

Effects of cyclic analogs of GABA on protein synthesis and discrimination learning.

Three cyclic analogs of gamma-aminobutyric acid (GABA)-5-ethyl, 5-phenyl, 2-pyrrolidinone (EPP), 5-diphenyl, 2-pyrrolidinone (DPP), and 5-methyl, 5-phenyl, 2-pyrrolidinone (MPP)- were studied in relation to protein synthesis and the latter in relation to discrimination learning. The present study shows that when different groups of rats were injected subcutaneously with 10 mg/kg of EPP or DPP, the protein synthesis in vitro was inhibited 75% in brain mitochondria. MPP at the same doses was the less potent inhibitor of mitochondria protein synthesis. Experiments on discrimination learning show that 10mg/kg of MPP enhance the response decision speed in presence of S(+) (white arm) and S(-) (black arm).

Animals↗

PubMedDate not supplied

Neonatal exposure to triethyltin disrupts olfactory discrimination learning in preweanling rats.

Triethyltin is an organotin compound that is known to produce neurotoxicity in both adult and developing organisms. Although this neurotoxicity has been documented with a variety of behavioral and biological measures, the effects of this compound on learning during early development have been less extensively studied. The present study reports four experiments that examined this question with an odor aversion learning paradigm in which pups received presentations of one odor paired with footshock and an alternate odor without shock. In Experiment 1, Long-Evans rat pups were injected IP on postnatal day 5 (PND 5) with either 0, 3 or 5 mg/kg TET and then tested for olfactory discrimination learning on PND 18. Only the 5-mg/kg dose impaired discrimination learning. In Experiment 2, PND 5 exposure to TET (5 mg/kg) disrupted olfactory learning on PND 18 but not on PND 12, whereas exposure on PND 10 disrupted learning at both ages of testing. In Experiment 3, PND 16 exposure to TET (5 mg/kg) also disrupted acquisition of olfactory learning on PND 18 but had no effect on retention of an olfactory discrimination that was acquired prior to TET exposure (i.e., on PND 14 and PND 15). Unconditioned responses to footshock were also unaffected by TET (Experiment 4). These findings indicate that neonatal exposure to TET impairs associative learning in developing rats and are discussed in relation to other studies of the developmental neurotoxicity of this compound.

Aging↗

PubMed1992

Effects of dihydroergotoxine on central cholinergic neuronal systems and discrimination learning test in aged rats.

We evaluated changes in the cholinergic neuronal system and learning ability with aging. Choline acetyltransferase (ChAT) activity, a presynaptic index of the cholinergic system, was decreased in the cerebral cortex, hippocampus, striatum, and hypothalamus in the brain of aged rats compared with young adults. Muscarinic cholinergic binding sites (receptors, MCR), a postsynaptic index of the cholinergic system, were markedly decreased in all areas of the brain. However, intraperitoneal injection of 1 mg/kg of dihydroergotoxine (DHET) for 14 days normalized both ChAT and MCR in the cerebral cortex and hippocampus. In the striatum, ChAT was normalized, but MCR did not recover. Aged rats showed marked learning impairment in a 30-day operant type brightness discrimination learning test. Daily DHET administration restored the discrimination ability in the aged rats to nearly the young adult level. DHET had no effects on central cholinergic indices or learning test results in young adult rats. These findings suggest that learning is impaired in aged rats due to impairment in the central cholinergic neuronal system, and that DHET normalizes the decreased function in this system, restoring the learning ability.

Aging↗

PubMed1989

Effect of piracetam, a nootropic agent, on discrimination learning deficits induced by parental undernutrition and environmental impoverishment in young rats.

The study was conducted on 64 Charles Foster albino rats which were equally distributed into 8 even-matched groups, following a 2 x 2 x 2 factorial design by varying three independent factors at two levels: nutrition--normal and undernutrition, environmental--enrichment and impoverishment, and drug treatment--vehicle and piracetam (100 mg/kg, ip). Prenatal nutrition was induced by restricting the mother's food intake. The environmental enrichment/impoverishment and the vehicle/drug treatments were given during the postweaning period of the rat pups. The animals were subjected to original and subsequent reversal brightness discrimination learning tests in a single unit T-maze at 8-9 weeks of age. The results indicate that undernutrition and environmental impoverishment significantly attenuated the original discrimination as well as the reversal discrimination learning. Piracetam treatment improved the learning performance of normally reared rats and also attenuated the original and reversal learning deficits induced by prenatal undernutrition and postnatal impoverishment. The results indicate that piracetam may be useful in memory deficits induced by malnutrition.

Analysis of Variance↗