PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “DISCRIMINATION LEARNING”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1982

Concept learning by retarded children: a comparison of three discrimination learning procedures.

The effectiveness of stimulus delay and stimulus fading procedures was compared with differential reinforcement only in training developmentally delayed children on a concept learning task. Twenty-four children were randomly assigned to one of the three treatment conditions. All three experimental conditions contained five discrimination programmes, each designed to teach the child to discriminate one pair of exemplars from the target concepts bottle and jar. Following successful completion of one training programme, a concept acquisition probe was administered to determine whether the target concepts had been engendered. Alternate presentations of successively different training programmes and concept acquisition probes were continued until the subject passed the probe, failed to complete a training programme, or completed all five training programmes. Five 'stimulus fading' subjects, three 'stimulus delay' subjects, and four 'reinforcement only' subjects learned the concepts. All children who learned to discriminate one pair of exemplars displayed conceptual behaviour after training on two or fewer pairs of exemplars. It was suggested that the absence of pronounced differences between conditions may have been due to the complexity of the task or the type of prompts employed.

Child, Preschool↗
PubMed2006

Roles of the auditory cortex in discrimination learning by rats.

We investigated the roles of the auditory cortex in sound discrimination learning in Wistar rats. Absolute pitch or relative pitch can be used as discrimination cues in sound frequency discrimination. To clarify this, rats were trained to discriminate between rewarded (S+) and unrewarded (S-) test stimuli (S+ frequency>S- frequency). After learning was acquired by rats, performance was tested in a new test in which S+ frequency was constant but S+ frequency S- frequency but both frequencies were increased. If the discrimination cue of the first test was preserved in the new test, performance following change of testing procedures was expected to remain high. The measured performance suggested that rats used relative pitch in half octave discrimination (difference between S+ and S- frequencies, 0.5 octave), and absolute pitch in octave discrimination (difference between S+ and S- frequencies, 1.0 octave). Bilateral lesions in the auditory cortex had almost no effect on performance before procedure change. Furthermore, performance following procedure change was not affected by lesions in the auditory cortex when the discrimination cue was preserved. However, performance was impaired by lesions in the auditory cortex when a new discrimination cue was used following procedure change. Lesions in the auditory cortex also impaired multimodal discrimination between sound and sound plus light. The present findings suggest that the auditory cortex plays a role as a sensory interface of the higher cortices required for flexible learning and multimodal discrimination.

Acoustic Stimulation↗
PubMed2000

Selective attention in animal discrimination learning.

The traditional approach to the study of selective attention in animal discrimination learning has been to ask if animals are capable of the central selective processing of stimuli, such that certain aspects of the discriminative stimuli are partially or wholly ignored while their relationships to each other, or other relevant stimuli, are processed. A notable characteristic of this research has been that procedures involve the acquisition of discriminations, and the issue of concern is whether learning is selectively determined by the stimulus dimension defined by the discriminative stimuli. Although there is support for this kind of selective attention, in many cases, simpler nonattentional accounts are sufficient to explain the results. An alternative approach involves procedures more similar to those used in human information-processing research. When selective attention is studied in humans, it generally involves the steady state performance of tasks for which there is limited time allowed for stimulus input and a relatively large amount of relevant information to be processed; thus, attention must be selective or divided. When this approach is applied to animals and alternative accounts have been ruled out, stronger evidence for selective or divided attention in animals has been found. Similar processes are thought to be involved when animals search more natural environments for targets. Finally, an attempt is made to distinguish these top-down attentional processes from more automatic preattentional processes that have been studied in humans and other animals.

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↗
PubMedDate not supplied

[A new simplified model of discrimination learning in mice].

A new technically simple and procedurally easy model of discrimination learning in mice has been proposed. The model allows to reach a quick rate of learning; to use the various characteristics of objects (form, color, size, etc) within the same sensory modality as a conditional stimulus; to transfer discrimination from one signal characteristic to the other (for instance from a color to a size); and to assess behaviour in a situation closely approached to conditions of the natural environment.

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↗
PubMed1999

Visual discrimination learning under switching procedure in visually deprived cats.

Previous studies have shown that fine visual discrimination learning is severely impaired in cats binocularly deprived in the early period of life (BD cats) and also somewhat in control cats reared with open eyes in the limited laboratory environment (C cats) compared with cats reared in a normal rural environment (N cats). It was concluded that visual deprivation impairs perceptual learning. In the present study discriminative stimuli were dissimilar and so the task was perceptually easy, but using a switching procedure made it associatively difficult. In regular trials a gate with a grating pattern was positive and a blank gate negative, whereas in switching trials the meaning of the gates was reversed. The switching stimulus was intermittent light in some stages of training and intermittent tone in others. Learning was severely impaired in BD cats and somewhat in C cats and the deficit was similar under visual and auditory switching. Thus, early visual deprivation impairs associative learning. The impairment probably includes associations between switching stimulus and instrumental responses and configural associations between switching stimulus and discriminative stimuli.

Animals↗
PubMed1974

On the nature of non-responding in discrimination learning with and without errors.

In human subjects, discrimination learning with errors results in active responding incompatible with the reinforced response. The direction of such incompatible behavior is opposite to that of the reinforced response. Responding occurs only during the stimulus correlated with extinction. The frequency of active non-responding is maximal shortly after the start of discrimination training (the time at which the frequency of errors decreases most rapidly) and approaches zero as discrimination training continues. The magnitude of behavioral contrast is not related systematically to the number of errors. Instead it is related directly to the frequency of active non-responding. Active non-responding appears to be motivated by the aversiveness of self-produced frustration, in the sense that active non-responding allows the subject to avoid the aversiveness of non-reinforced responding.

Journal Article↗
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↗
PubMed1994

Nalorphine as a stimulus in drug discrimination learning: assessment of the role of mu- and kappa-receptor subtypes.

Using the conditioned taste aversion baseline of drug discrimination learning, animals were trained to discriminate nalorphine from distilled water. In subsequent generalization tests, the mu-opiate agonist morphine substituted for the nalorphine stimulus in a dose-dependent manner, while the kappa-opiate agonist U50,488H and the mu-opiate antagonists naloxone and naltrexone failed to do so. That the mu-agonist morphine substituted for the nalorphine stimulus while a kappa-agonist and mu-antagonists failed to substitute indicate that the discriminative control that was established with nalorphine in the present study was mu-agonist receptor-mediated. The basis for this selective control by the mu-receptor subtype may be related to the relative salience of receptor activity in opiate-naive animals. The present results suggest that discriminative control by compounds with activity at multiple receptor sites is not uniformly mediated by specific activity at all of those sites. The specific site mediating discriminative control appears to be a function of the specific training drug.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Effects of discrimination learning on the rat amygdala dopamine release: a microdialysis study.

Extracellular levels of dopamine (DA) and its metabolites were monitored with the in vivo microdialysis method in the amygdala of rats while and after they performed a discrimination learning task or a non-discrimination task. A group of rats was trained to discriminate between lamp-on and lamp-off states under an operant-type learning procedure. After a stable discriminative behavior was established, a dialysis probe was inserted into the basolateral amygdaloid nucleus of each rat. The concentrations of DA and its metabolite 3,4-dihydroxyphenylacetic acid significantly increased during the learning sessions as compared to their basal levels. In contrast, another group of rats trained on a similar, but non-discriminative task showed no such increases. These results suggest that the dopaminergic neural systems in the basolateral amygdaloid nucleus are activated during ongoing behavior maintained under the discrimination learning situation.

Amygdala↗
PubMed1993

Neonatal glutamate can destroy the hippocampal CA1 structure and impair discrimination learning in rats.

Neonatal Wistar rats were subcutaneously injected with 0.1, 1, or 2 mg/g b.wt. of monosodium glutamate (MSG) at 1, 3, 5, 7, and 9 days after birth. The animals were observed for degeneration of pyramidal cells in the hippocampus. The histological change disappeared when the animals were concurrently injected with glutamate diethyl ester (GDEE), an antagonist of the glutamate receptor. When light-dark discrimination learning was carried out at 10 weeks old, the correct response in the acquisition period was impaired in the animals given 1 and 2 mg/g of neonatal MSG. Their retention scores were also impaired in comparison with the control animal. The behavioral impairment recovered with pre-treatment with GDEE. No significant changes were observed in the concentrations of transmitter substances, including amino acids and monoamines. These results suggest that neonatal MSG destroys the hippocampus and impairs acquisition and retention of discrimination learning through the mechanism of glutamate receptors.

Animals↗
PubMed1993

Buprenorphine as a stimulus in drug discrimination learning: an assessment of mu and kappa receptor activity.

Using the conditioned taste aversion baseline of drug discrimination learning, different groups of animals were trained to discriminate either buprenorphine or morphine from distilled water. Specifically, animals were injected with buprenorphine or morphine prior to a saccharin-LiCl pairing and the drug vehicle prior to saccharin alone. By the fifth conditioning trial, animals differentially consumed saccharin on the basis of administration of the drug or its vehicle. In subsequent generalization tests, buprenorphine stimulus control generalized completely to the mu agonist morphine in four of the five subjects tested, while morphine stimulus control completely generalized to buprenorphine in two of five subjects and partially generalized in the remaining three. Buprenorphine failed to generalize to the relatively selective kappa antagonist MR2266 and the broad-based antagonist diprenorphine. Morphine also failed to generalize to MR2266, but did generalize to diprenorphine. That morphine and buprenorphine displayed some degree of cross-generalization suggests that these compounds share some stimulus property, presumably their agonist activity at the mu receptor, and that the mu activity of these compounds was used in the establishment of the discrimination, a conclusion supported by the fact that compounds with mu antagonist activity (e.g., naloxone, MR2266) blocked both buprenorphine and morphine stimulus control. That buprenorphine failed to generalize to compounds with kappa antagonist activity suggests that animals trained to discriminate buprenorphine from its vehicle do not use the kappa antagonist activity of the drug in the establishment of the discrimination. The basis for the differential ability of various receptor subtypes to mediate the discriminative properties of compounds with mixed receptor activity was discussed.

Animals↗
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↗
PubMedDate not supplied

Visual-discrimination learning ability and beta-amyloid accumulation in the dog.

Young, middle-aged, and old beagle dogs were tested on several visual-discrimination tasks: reward- and object-approach learning, object discrimination and reversal, long-term retention of a reversal problem, and a size-discrimination task. Beta-amyloid accumulation in the entorhinal, prefrontal, parietal, and occipital cortices was quantified using immunohistochemical and imaging techniques at the conclusion of cognitive testing. Middle-aged and old dogs were impaired in size-discrimination learning. In each task, a subset of aged dogs was impaired relative to age-matched peers. Beta-amyloid accumulation was age-dependent. However, not all middle-aged and old dogs showed beta-amyloid accumulation in the entorhinal cortex. The error scores from dogs tested with a nonpreferred object during visual discrimination learning and from reversal learning were correlated with beta-amyloid in the prefrontal but not entorhinal cortex. Size-discrimination and reward and object-approach learning error scores were correlated with beta-amyloid accumulation in the entorhinal but not prefrontal cortex. The results of these studies support an association between cognitive test and the location and extent of beta-amyloid pathology.

Amyloid beta-Peptides↗