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
PubMed1983

Concept discrimination learning by preschool children using facial stimuli differing in age, sex, race, and eyeglasses.

In two experiments, the relative salience of the variables age, sex, race, and eyeglasses was determined with the use of a discrimination learning task and preschool-age Ss. The stimuli for the task were 112 frontal head and shoulder color photographs arranged in pairs. In both experiments, sex discrimination was the easiest to learn, followed by race and age, which did not differ from each other. Each of the variables of sex, age, and race, however, proved to be more salient than glasses which was not learned by any of the 19 Ss who were given a glasses discrimination problem in Experiment 1. Interestingly, specific cue salience may be a more valid concept than dimensional salience for preschool children. This was indicated by the asymmetry in performance on the black and white racial discrimination problems and on the male and female sexual discrimination problems: both black and male were significantly easier to learn.

Age Factors↗
PubMed1988

Conditional discrimination learning in Aplysia californica.

Two experiments examined whether the relation between a conditioned stimulus (CS) and an unconditioned stimulus (US) might be brought under the control of contextual stimuli in the invertebrate Aplysia californica. Subjects received exposure to 2 different contexts. In both experiments, a tactile CS was paired with a shock US in one of those contexts. In the other context, that tactile CS was either nonreinforced (Experiment 1) or explicitly unpaired with the shock US (Experiment 2). Responding to the CS during a subsequent test was greater in the context in which that CS had been paired with the US compared with the context in which it had been nonreinforced or unpaired. These findings are discussed in terms of theories of conditional discrimination learning.

Animals↗
PubMed1975

Form preferences in successive discrimination learning of young chicks.

In four experiments the effects of form and orientation pecking preferences of 1- and 3-day old Vantress X Arbor Acre chicks on successive discrimination learning were determined, using heat reinforcement. Major findings were as follows: (a) The young chick has both circle and verticle orientation pecking preferences that are present during at least the first 3 days after hatching; (b) when either of these preferred cues is the nonreinforced cue, the young chick has difficulty in learning not to respond to it but learns quickly not to respond to an unpreferred cue (e.g., triangle and horizontal oriented dots or bar); and (c) these pecking preferences can be modified by heat reinforcement, and the effects of this conditioning is evidenct in subsequent extinction and retention tests. The main conclusion from these experiments is that form and orientation preferences, like brightness and color preferences, are important developmental constraints on conditioning of the young chick.

Age Factors↗
PubMed1979

Aging in the rhesus monkey: effects on visual discrimination learning and reversal learning.

The behavior of aged rhesus monkeys (18 years and older) was compared to that of young monkeys (3 to 6 years old) to evaluate their relative abilities to learn a series of visual discrimination and discrimination reversal problems. Using a subject-paced, automated experimental procedure designed to optimize stimulus control and facilitate execution of choice responses, no consistent age-related differences were observed in the ability to learn new color and pattern discrimination problems of varying difficulty. However, a severe and consistent deficity on reversal learning did occur. A detailed analysis of this deficit revealed that not only did the aged monkeys take longer to extinguish the old habit and return to chance performance, but they continued to display a deficit in establishing accurate performance at above-chance levels as well. Since no reliable age differences were observed on the original discrimination learning problems, these data suggest that aging impairs mechanisms involved with response rigidity and/or susceptibility to intertrial proactive interference, more severely than those involved with the simple formation of new associations.

Aging↗
PubMed1995

Nitric oxide synthase inhibition does not impair visual or spatial discrimination learning.

Nitric oxide (NO) is a candidate retrograde messenger involved in synaptic plasticity, and is linked to the cholinergic system in the brain. We examined the role of NO in the acquisition of visual and spatial discriminations by daily administration of either saline or 1-nitroarginine methyl ester (L-NAME), an NO synthase inhibitor. Brains were assayed for NO synthase activity and two presynaptic cholinergic markers: hemicholinium-3 (HC-3) binding, which determines the number of sodium-dependent high-affinity choline uptake sites, and activity of choline acetyltransferase (ChAT), which is the synthetic enzyme for acetylcholine. In both behavioral tasks, the acquisition rate was not different between groups. L-NAME reduced NO synthase activity by 85% in all brain areas assayed and HC-3 binding by 38% in hippocampus and 48% in posterior cortex. ChAT activity was not different between groups in any region assayed. These data suggest that NO does not play a role in visual or spatial discrimination learning. However, NO synthase inhibition may play a role in the regulation of cholinergic activity.

Animals↗
PubMed1981

Inheritance of discrimination learning ability and retention in BA and DBA mice.

Male house mice from two inbred strains, DBA/2 and BA, and their F1 and F2 crosses and backcrosses, B1 and B2, were tested for black-white discrimination learning and 24-hr response retention in a water maze. The BA strain exhibited an inferior learning performance. Nonparametric and biometrical genetic analyses provided only weak evidence of unifactorial inheritance of acquisitions, but somewhat stronger evidence in the case of retention.

Animals↗
PubMed1993

Long-term potentiation in rat piriform cortex following discrimination learning.

The behavioral conditions for induction of long-term potentiation (LTP) elicited by unilateral patterned electrical stimulation of the lateral olfactory tract (LOT) was studied in piriform cortex. A group of animals was trained to discriminate two natural odors while another group was trained to discriminate a patterned stimulation (bursts of 4 pulses at 100 Hz repeated at 160-ms intervals) used as an olfactory cue, versus a natural odor. Both groups were successful in the discrimination and no statistical significant difference was observed in behavioral data between these two groups on series of 5 successive daily training sessions. With animals trained to perform the task with the artificial cue, monosynaptic responses evoked by single pulse stimulation of the LOT were collected, prior to and just after each of the successive training sessions. Comparisons with behavioral data collected at the beginning and the end of a training session revealed that the population synaptic responses increased with the percentage of correct responses performed by the animals. This increase (LTP) was progressive and present only when significant discrimination between the two cues was observed. A positive correlation was found between the increase in monosynaptic responses and the level of performance. Responses elicited by control electrodes were slightly depressed at the end of the discrimination learning series. In addition, when a group of naive animals was pseudoconditioned, giving the patterned electrical stimulation for the same number of sessions but without any olfactory training, no LTP was recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Autoshaped discrimination learning in chicks incubated under normobaric hyperoxia.

White Leghorn chicken eggs were exposed to either 60% O2 or room air (21% O2) for the first 19 days of incubation. Chicks that hatched from these eggs were then tested in discrimination learning tasks in which keypecking was autoshaped to colored lights that were paired with either access to food (Experiment 1) or heat (Experiment 2). Chronic prenatal exposure to 60% O2 reduced hatchability but did not affect mean hatching time. Although previous research has shown that hyperoxic treatment accelerates growth in chick embryos until the 18th day of incubation, experimental chicks weighed either the same (Experiment 1) or less (Experiment 2) than controls at hatching. Prenatal exposure to hyperoxia depressed rate of acquisition, but not final performance level in both discrimination tasks. The initial performance deficit appeared to reflect a temporary depression of activity or arousal, possibly due to a relatively greater hypothermia in experimental chicks. This general pattern of results was attributed to premature depletion of essential nutrients within the egg as a result of oxygen-induced growth acceleration.

Animals↗
PubMed1987

Qualities and locations of stimuli and responses affecting discrimination learning of chinchillas (Chinchilla laniger) and pigeons (Columba livia).

Chinchillas and pigeons were used as subjects in separate experiments to study interactions among stimulus and response characteristics in discrimination learning. Both the stimuli and the responses could differ with respect to their "quality" and their "location." Bright versus dim lights and upper versus lower lights served as the stimulus qualities and stimulus locations for the chinchillas, respectively. Red versus green lights and upper versus lower lights served as the stimulus qualities and stimulus locations for the pigeons, respectively. Respond versus no-respond and respond-left versus respond-right served as the response qualities and response locations, for both species, respectively. In both experiments, response-quality performance was superior when the discriminative stimuli differed in quality than when they differed in location, whereas response-location performance was superior when the discriminative stimuli differed in location than when they differed in quality. These results were interpreted within the framework provided by a general law of learning, that is, the "quality-location hypothesis."

Animals↗
PubMed1981

Drug discrimination learning in lead-exposed rats.

Lead acetate (0.02 or 0.5 percent) was administered to dams throughout the lactation period with half of the litters continuing on lead after weaning. Drug thresholds for d-amphetamine were determined by using the drug-discrimination learning paradigm. All the offspring that had been exposed to lead were less sensitive to the stimulus properties of d-amphetamine irrespective of whether or not they had continued on lead after weaning.

Animals↗
PubMed1995

Shifting behavior: an analysis of response patterns of Parkinson patients in discrimination learning.

Parkinson patients often show decreased performance on what is generally referred to as "shift tasks." This does not necessarily imply that Parkinson patients have problems with shifting, since task performance reflects not only shifting but also other factors. Using a discrimination learning task, we analyzed response patterns to determine the decision rules used. As well, we varied the manner of problem alternation (implicit versus explicit) and the type of problem alternation (extradimensional versus intradimensional shifts). In accordance with the literature, we found that Parkinson patients needed more trials to solve the problems. However, the response patterns of the Parkinson patients and controls were practically the same. An important finding was that Parkinson patients did not hold on longer to a rule, which was correct in a former problem, than controls did. Therefore, we concluded that Parkinson patients are able to shift from one decision rule to another.

Adult↗
PubMed1985

Visual discrimination learning with variable irrelevant cues in autistic children.

Ten autistic children and 10 normal nursery school children, matched for mean developmental age of 4 years 9 months, were presented with figure stimuli that had variable irrelevant cues in two-choice simultaneous discrimination learning. The first condition was a control condition in which an irrelevant cue was held constant throughout the experiment. The second condition had an irrelevant cue varied between trials. The third condition varied irrelevant cues both within and between trials. The autistic group showed roughly equivalent performances in the three conditions except that the performance tended to be higher in the second than in the third condition. The normal group, on the other hand, showed the best performance in the first control condition and the poorest performance in the third condition. In the present experiment, the performance of the autistic group did not vary as a function of irrelevant variability. It was suggested that this result was due to the poor performance of the first control condition and was discussed in terms of ability of stimulus compounding of autistic children.

Attention↗
PubMed1993

Cognitive strategies and hypothesis testing during discrimination learning in Parkinson's disease.

This study investigated the nature and extent of impairments in the use of hypotheses and cognitive strategies in medicated subjects with idiopathic Parkinson's disease (PD) and matched control subjects. PD subjects did not differ from controls in solving one- or two-dimensional discrimination learning problems, but showed impairment on four-dimensional problems which did not appear to be attributable to memory deficits. They achieved fewer correct solutions, used fewer hypotheses, and were less likely to use appropriate lose-shift strategies following negative feedback. The pattern of findings was similar to those previously reported for subjects with frontal lobe lesions.

Aged↗
PubMed1989

Y-chromosomal effects on discrimination learning and hippocampal asymmetry in mice.

From a four-way cross between unrelated inbred strains of mice, a random-breeding line was developed that segregated at two coat-color loci and carried Y chromosomes from different sources. Adult males were used for measurements of black-white discrimination learning and 7-day response retention in a water maze, body weight, brain weight, and left- and right-side hippocampus weight. Clear evidence was obtained of Y-linked influences on response acquisition, body weight, right-side hippocampus weight, and hippocampal asymmetry, whereas direct effects of autosome 9 were indicated with regard to right-side hippocampus weight only. However, epistatic interactions of the Y chromosome with autosome 9 were found for response acquisition and body weight and with autosome 4 for hippocampal asymmetry.

Animals↗
PubMed1989

The effects of haloperidol on discrimination learning and behavioral symptoms in autistic children.

This double-blind and placebo-controlled clinical trial in autistic children had three objectives: (a) to replicate earlier findings that haloperidol administration is associated with a significant reduction of behavioral symptoms; (b) to further assess its safety when given on a short-term basis; and (c) to assess whether it has an effect on discrimination learning. Forty-five children, 2.02 to 7.58 years old (M = 4.49), completed this crossover design, with random assignment to treatment sequences. Haloperidol was shown to be a powerful therapeutic agent when administered for 4 weeks and free of side effects; at doses ranging from 0.25 to 4.0 mg/day (M = 0.844), there was a clinically and statistically significant reduction of a variety of symptoms. Under the given conditions, the children failed to learn on either haloperidol or placebo.

Autistic Disorder↗
PubMed1994

Magnetic field effects on spatial discrimination learning in mice.

A magnetic sense has been demonstrated in several species, including mice. It has been suggested that the basis of this sense, and its role in navigation, rests on the existence of ferromagnetic materials in the brain. Several researchers have shown changes in navigation during exposure to relatively weak magnetic fields, which presumably interact with magnetite in the brain. In this study, mice were exposed to the powerful magnetic field of an MRI scanner and their left-right discrimination learning was compared with a control group. Results indicate a significant decrement in such learning ability immediately after exposure. Suggestions for future research are presented.

Animals↗