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At least 1,297 records · Page 72Linked to original sources
PubMed1997

Synaptic vesicle ultrastructural changes in the rat hippocampus induced by a combination of alpha-linolenate deficiency and a learning task.

Rats fed either a safflower oil (alpha-linolenate-deficient) or a perilla oil (alpha-linolenate-sufficient) diet through two generations (F1) showed significant differences in the brightness-discrimination learning task. In this task, correct responses were lever-pressing responses, which were reinforced with dietary pellets, and incorrect responses were those with no reinforcement. The inferior learning performance in the safflower oil group was caused mainly by the inferior ability to rectify the incorrect responses through the learning sessions. In the safflower oil group after the learning task, the average densities of synaptic vesicles in the terminals of the hippocampus CA1 region were decreased by nearly 30% as compared with those in the perilla oil group, and it is notable that this difference was not detected without the learning task. These results suggest that dietary oil-induced morphological changes in synapses in the hippocampus of rats are related to the differential learning performance and that the turnover rate of synaptic vesicles in the hippocampus may be an important factor affecting learning performance.

Animals↗
PubMed1984

Curiosity and demographic factors as determinants of children's probability-learning strategies.

Children's curiosity, gender, activity level, and socioeconomic status (SES) were related to their performance on a partially reinforced discrimination-learning task. The 38 boys and 37 girls were in the first grade and were all white. Three factors of curiosity (manipulatory, conceptual, and about the complex) were assessed. Performance on the learning task was scored for the number of correct responses (maximizing) and for the frequency of three-step sequences reflecting variability, systematic patterning, and perseveration. In general, the three curiosity factors related negatively to maximizing and perseveration and positively to variability. (The same effects were found for activity level.) Systematic patterning related positively to one curiosity type and negatively to another. Girls used less maximizing and more systematic patterning than boys. The response choices of girls were affected more by differences in conceptual curiosity and those of boys by differences in curiosity about the complex. Activity level was unrelated to gender but differed with SES. The findings demonstrate the role of different curiosity factors in shaping response sequences and suggest some reasons for children's choice of probability-learning strategies.

Child↗
PubMed1965

DISCRIMINATED TIME-OUT AVOIDANCE IN PIGEONS.

Performances of two pigeons were studied on a concurrent discriminated TO avoidance-VR schedule. Each avoidance response postponed a TO from a VR 140 for a specified RS interval. The warning stimulus on the TO avoidance schedule was a discontinuous clock which consisted of a series of discrete color changes that varied systematically with the RS interval. Experimental manipulations established that the avoidance behavior was under the control of the avoidance schedule and the discontinuous clock. Five-min TOs maintained higher avoidance rates than shorter TO durations; a 15-min TO maintained less avoidance responding than the 5-min TO. Chlorpromazine hydrochloride increased TO avoidance behavior and decreased concurrent VR behavior.

Animals↗
PubMed1963

Sodium chloride deprivation: development of sodium chloride as a reinforcement.

The effects of deprivation of dietary sodium chloride on operant behavior reinforced by water and sodium chloride were studied. Rats responded at high rates for sodium chloride reinforcements only after they had been fed an inadequate diet for 40 days. These effects were specific to the deprived element of the diet.

Animals↗
PubMed2002

Dopamine D2L receptor knockout mice display deficits in positive and negative reinforcing properties of morphine and in avoidance learning.

The dopamine D2 receptor (D2) is implicated in drug addiction, learning and memory. Two isoforms of the D2 receptor, termed D2L (long form) and D2S (short form), have been identified. We previously generated mice lacking D2L (D2L-/-), but expressing functional D2S. In this study, we investigated the role of D2L in the positive and negative reinforcing properties of abused drugs and electrical stimuli, using D2L-/- mice as a model system. Mice were trained in three associative learning tasks: conditioned place preference to morphine and cocaine, conditioned place aversion to naloxone-precipitated morphine withdrawal, and active avoidance. D2L-/- mice, like wild type mice, developed a place preference to cocaine. In contrast to wild type mice, D2L-/- mice did not develop a place preference to morphine, nor did they attain a place aversion to morphine withdrawal. D2L-/- mice also failed to acquire avoidance behavior in response to electrical stimuli. There were no significant differences between D2L-/- and wild type mice in mu-opioid receptor density, morphine-induced locomotor stimulation and morphine withdrawal symptoms. These results suggest that D2L may have a greater impact than D2S on the rewarding aspects of morphine, and the aversive properties of morphine withdrawal and electrical stimulus. These findings also suggest that the presence of D2L is critical in the acquisition (learning) and/or retention (memory) of context-stimulus associations in certain situations. On the other hand, D2L is not essential for the rewarding aspects of cocaine and for the development of morphine dependence. Thus, these studies reveal distinct functional roles of D2L and/or D2S in drug addiction and avoidance learning, which may lead to a better understanding of the neurobiological basis underlying these behaviors.

Animals↗
PubMedDate not supplied

[Learning to differentiate microintervals of time using verbal feedback].

Reaction time (RT) and the number of correct estimations of time microintervals (10 and 180 ms) between two visual stimuli were recorded in healthy subjects. It has been shown that 10 ms interval is better estimated when the stimuli are presented in the right visual field, i.e. when they are addressed directly to the left hemisphere. At the same time the number of correct estimations of 180 ms interval is greater and their RT is less when the stimuli are addressed directly to the right hemisphere. This points to different hemispheric mechanisms of time microintervals estimation. Study of the influence of different forms of verbal reinforcement on this learning has shown that after positive reinforcement (the word "good") the number of correct estimations is on average by 10% greater than after negative reinforcement (the word "error"). This may be connected with such processes as isolation and identification of erroneous reaction.

Adult↗
PubMed1971

Caudate nucleus stimulation retroactively impairs complex maze learning in the rat.

Rats, with permanent electrodes implanted bilaterally in the caudateputamen complex, were stimulated with single pulses after reinforcement of each maze learning trial or were stimulated with multiple pulses after each choice point or after reinforcement. Single pulses retarded the development of learning only when stringent learning criteria were required, whereas multiple pulses interfered with acquisition when the criteria for learning were less difficult.

Age Factors↗
PubMed1981

Clinical biofeedback: a behavioral analysis.

Clinical biofeedback studies have shown that patients can learn to control highly specific physiological responses such as relaxation of the internal anal sphincter, contraction of the external anal sphincter, heart rate and intracardiac conduction patterns, or blood pressure. Findings from a number of studies indicate that the ability to learn to control abnormal responses is highly reinforcing and facilitates further learning. Other findings indicate that learning tends to be specific to the response being trained. If it is desirable to teach patients to control more than one response, it may be necessary to teach each response independently.

Behavior Therapy↗