Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “learning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 595 records · Page 33Linked to original sources
PubMed2002

Quokkas (Setonix brachyurus) demonstrate tactile discrimination learning and serial-reversal learning.

Two male quokkas (Setonix brachyurus: a herbivorous macropod marsupial) were trained to discriminate pairs of stimuli in the laboratory. Quokkas indicated their choice by pulling on 1 of 2 simultaneously presented cords. The quokkas' discrimination abilities were tested on 6 tactile and 6 visual discrimination tasks. Correct responses were rewarded with food. For both quokkas, all tactile tasks were learned to a criterion of 75% correct in up to 4 20-trial sessions. No visual task maintained criterion performance in 4 sessions. One tactile discrimination was reversed 10 times. After the 1st reversal, the error rate declined sharply and fell to a level well below the initial discrimination.

Animals↗
PubMed2002

Analysis of the perceptual learning effect in flavour aversion learning: evidence for stimulus differentiation.

Rats received exposure to two compound flavours, AX and BX, where A and B were sucrose and saline and X was acid. For group intermixed (1), exposure consisted of alternating trials with AX and BX; group blocked (B) received a block of AX trials and a separate block of BX trials. Experiment 1 showed that generalization to BX after conditioning with AX was less profound in group 1 than in group B. Separate examination of the elements of the compound showed that the source of this difference lay in the strength acquired by the X element. X acquired less strength in group 1 than in group B (Experiments 1 and 2), whereas for the A element (Experiments 3 and 4) the reverse pattern was obtained. These results support the proposal that the perceptual learning effect (restricted generalization from AX to BX in group 1) depends on a process that enhances the effectiveness of unique stimulus elements (A and B) and reduces that of common elements (such as X).

Animals↗
PubMed2001

Interference with judgements of control and learning as a result of prior exposure to controllable and uncontrollable feedback during concept-learning tasks.

Two experiments examined whether exposure to an uncontrollable relationship between an action and its outcome during a nonaversive pretreatment phase would attenuate subsequent ratings of control given to actions emitted by subjects. In Experiment 1, such an interference effect was demonstrated relative to a group that received prior training with a controllable action-outcome relationship, and relative to a group not exposed to any prior relationship. In Experiment 2, these effects were replicated, and interference was also found to occur when learning a maze task. Thus, the effects of helplessness were shown to be quite general, to be produced by a nonaversive induction procedure, and to occur most readily when the current contingency between action and outcome was weakest.

Adolescent↗
PubMed2004

AX+, BX- discrimination learning in the fear-potentiated startle paradigm: possible relevance to inhibitory fear learning in extinction.

The neural mechanisms of fear suppression most commonly are studied through the use of extinction, a behavioral procedure in which a feared stimulus (i.e., one previously paired with shock) is nonreinforced repeatedly, leading to a reduction or elimination of the fear response. Although extinction is perhaps the most convenient index of fear inhibition, a great deal of behavioral work suggests that postextinction training conditioned stimuli are both excitatory and inhibitory, making it difficult to determine whether a neural manipulation affects inhibition, excitation, or some combination thereof. For this reason we sought to develop a behavioral procedure that would render a stimulus primarily inhibitory while at the same time avoiding some of the issues raised by the traditional conditioned inhibition paradigm, namely second-order conditioning, external inhibition, and configural learning. Using the fear-potentiated startle paradigm, we adapted an AX+, BX- training procedure in which stimuli A and X were presented simultaneously and paired with shock, and stimuli B and X were presented simultaneously in the absence of shock. In testing, high levels of fear-potentiated startle were seen in the presence of A and AX and much lower levels were seen in the presence of B and AB, as would be predicted if stimulus B were a conditioned inhibitor. We believe this method is a viable alternative to the traditional conditioned inhibition training procedure and will be useful for studying the neural mechanisms of fear inhibition.

Acoustic Stimulation↗
PubMed1984

Do nutrient supplements and dietary changes affect learning and emotional reactions of children with learning difficulties? A controlled series of 16 cases.

Detailed dietary and biochemical analyses were done on 16 consecutive cases of children aged 5-15 years referred for a combined remedial reading/behaviour modification program. Each child was given an individually designed vitamin and mineral supplement. Diets were also changed to reduce sugars and refined foods and toxic metals contamination. Cases were matched in pairs with 16 other cases on the program who were given no dietary changes but who received a one-a-day vitamin/mineral capsule as part of standard procedure at the clinic. Over 22 weeks on the program, the experimental group showed significantly greater improvements than the control group in behaviour assessed at school, at home and in the clinic. The experimental group also made significantly greater gains in reading skills. Routine Stanford-Binet intelligence tests given at week 2 and week 20 or 21 showed increased IQ scores of 5 to 35 points (mean = 17.9) for the experimental group. Increases for the control group were 0-21 points (mean = 8.4). Results suggest that subtle nutritional variables exert a substantial influence on learning and behaviour.

Adolescent↗
PubMed1990

Learned self-help response to chronic illness experience: a test of three alternative learning theories.

The purpose of this study was to generate a self-help model depicting the essential dynamics of learned response to chronic illness experience. The method used to generate a self-help model was based on theoretical triangulation, as discussed by Houts, Cook, and Shadish (1986), Mitchell (1986), and Reichardt and Cook (1979). Theoretical triangulation, incorporating multiple perspectives and hypotheses in the same study, is a form of critical multiplism leading to testing of multiple rival hypotheses rather than single ones (Popper, 1972; Stinchcombe, 1968) and to construction of complex multivariate causal models instead of simple univariate ones (Blalock, 1961). Strong relationships were found between enabling skill, self-help, and life quality.

Adolescent↗
PubMed1988

Effects of signaling inescapable shock on subsequent escape learning: implications for theories of coping and "learned helplessness".

The present experiments reveal that shuttle-escape performance deficits are eliminated when exteroceptive cues are paired with inescapable shock. Experiment 1 indicated that, as in instrumental control, a signal following inescapable shock eliminated later escape performance deficits. Subsequent experiments revealed that both forward and backward pairings between signals and inescapable shock attenuated performance deficits. However, the data also suggest that the impact of these temporal relations may be modulated by qualitative aspects of the cues because the effects of these relations depended upon whether an increase or decrease in illumination (Experiment 2) or a compound auditory cue (Experiment 4) was used. Preliminary evidence suggests that the ability of illumination cues to block escape learning deficits may be related to their to reduce contextual fear (Experiment 3). The implications of these data for conceptions of instrumental control and the role of fear in the etiology of effects of inescapable shock exposure are discussed.

Adaptation, Psychological↗
PubMed2005

The learning curve for investigational surgery: lessons learned from laparoscopic diaphragm pacing for chronic ventilator dependence.

BACKGROUND: Electrical stimulation of the phrenic nerve motor point of the diaphragm through laparoscopic implantation of a pacing system is an option for high spinal cord-injured patients with chronic respiratory insufficiency. This study assesses the operative learning curve for the initial series of patients. METHOD: A series of six patients underwent laparoscopic placement of a diaphragm pacing system. The operative procedure was divided into the following four steps for analysis and rapid adjustment after each operation: exposure of the diaphragm, mapping of the phrenic nerve motor point, implantation of the pacing electrodes, and final routing of the wires to the external system. RESULTS: The first case required two operations, and the second case was unsuccessful because of a nonfunctioning phrenic nerve that led to a change in the preoperative screening criteria. The operative time decreased from 469 min for the first operation to 165 min for the sixth operation. The significant time decrease can be attributed to changes in the mapping and routing aspects of the operation. Key changes during this series that helped to reduce the operative time include abandonment of a software-dependent mapping technique, development of a grid algorithm for mapping, software improvement to increase the speed of stimulation and mapping, refinement of the mapping probe to maintain adequate suction on the diaphragm, shortening of the electrode lengths, and experience with the implantation of connections to the external electrodes. Presently, all five of the successfully implanted patients can be maintained on prolonged ventilatory support with the device. CONCLUSION: Analysis of every step of this investigational procedure enabled us to make rapid changes in surgical protocol, leading to decreases in operative times and expectant improvements in patient safety and efficacy. In this series, analysis was the key to developing a low-risk cost-effective outpatient diaphragm pacing system.

Adult↗
PubMed2006

Innovations in problem-based learning: what can we learn from recent studies?

This article aims at discussing the six papers included in this special issue on innovations in Problem-based learning (PBL). The papers address different aspects related to the implementation and the development of PBL. This discussion article highlights the relevance of the theme explored by each of the papers, the contributions emerging from the study to what is already known about that topic, and its limitations, particularly those that suggest directions for future research. Emphasis is given to new insights brought by the papers for better understanding tutorial group processes and self-study phase in PBL. The contributions provided by the papers are discussed in the light of pertinent literature and also in relation to their companion articles in this issue when indicated.

Cooperative Behavior↗
PubMed1983

Frequency judgment accuracy as a function of age and school achievement (learning disabled versus non-learning-disabled) patterns.

The accuracy of children's judgments of relative situational frequency was examined in two experiments. In Experiment 1 children with normal achievement in Grades 2 and 3 were compared with such children in Grades K and 5, as well as with three groups of low-achieving children in Grades 2 and 3. These latter groups consisted of children low in reading achievement, those low in math achievement, and those identified as learning disabled. Frequency judgment accuracy increased from kindergarten to Grades 2 and 3. No other comparisons yielded significant differences. Experiment 2 confirmed both the above age difference and the absence of any frequency judgment deficiency on the part of the low-achieving groups.

Achievement↗
PubMedDate not supplied

Lay midwife to nurse-midwife. Perceived learning needs and attitudes toward the learning experience.

This descriptive study was designed to identify the perceived learning needs of students with midwifery experience who enter nurse-midwifery education programs. Instruments were developed to gather data from nurse-midwifery educators and CNMs who had been experienced lay midwives (LM/CNMs). Results indicate that LM/CNMs and educators recognize the importance of identification of knowledge and skills gained before entering the educational program, but a variety of factors inhibit the implementation of creative, individualized curriculums. Issues related to nurse-midwifery education, including identification of valid knowledge and the need for a midwifery rather than obstetric model of teaching, are discussed.

Adult↗
PubMed2006

Impairment of the spatial learning and memory induced by learned helplessness and chronic mild stress.

Increasing evidences indicate the concurrence and interrelationship of depression and cognitive impairments. The present study was undertaken to investigate the effects of two depressive animal models, learned helplessness (LH) and chronic mild stress (CMS), on the cognitive functions of mice in the Morris water maze task. Our results demonstrated that both LH and CMS significantly decreased the cognitive performance of stressed mice in the water maze task. The escaping latency to the platform was prolonged and the probe test percentage in the platform quadrant was reduced. These two models also increased the plasma corticosterone concentration and decreased the brain derived neurotrophic factor (BDNF) and cAMP-response element-biding protein (CREB) messenger ribonucleic acid (mRNA) levels in hippocampus, which might cause the spatial cognition deficits. Repeated treatment with antidepressant drugs, imipramine (Imi) and fluoxetine (Flu), significantly reduced the plasma corticosterone concentration and enhanced the BDNF and CREB levels. Furthermore, antidepressant treated animals showed an ameliorated cognitive performance compared with the vehicle treated stressed animals. These data suggest that both LH and CMS impair the spatial cognitive function and repeated treatment with antidepressant drugs decreases the prevalence of cognitive impairments induced by these two animal models. Those might in part be attributed to the reduced plasma corticosterone and enhanced hippocampal BDNF and CREB expressions. This study provided a better understanding of molecular mechanisms underlying interactions of depression and cognitive impairments, although animal models used in this study can mimic only some aspects of depression or cognition of human.

Animals↗
PubMed2004

Learning at a distance I. Statistical learning of non-adjacent dependencies.

In earlier work we have shown that adults, young children, and infants are capable of computing transitional probabilities among adjacent syllables in rapidly presented streams of speech, and of using these statistics to group adjacent syllables into word-like units. In the present experiments we ask whether adult learners are also capable of such computations when the only available patterns occur in non-adjacent elements. In the first experiment, we present streams of speech in which precisely the same kinds of syllable regularities occur as in our previous studies, except that the patterned relations among syllables occur between non-adjacent syllables (with an intervening syllable that is unrelated). Under these circumstances we do not obtain our previous results: learners are quite poor at acquiring regular relations among non-adjacent syllables, even when the patterns are objectively quite simple. In subsequent experiments we show that learners are, in contrast, quite capable of acquiring patterned relations among non-adjacent segments-both non-adjacent consonants (with an intervening vocalic segment that is unrelated) and non-adjacent vowels (with an intervening consonantal segment that is unrelated). Finally, we discuss why human learners display these strong differences in learning differing types of non-adjacent regularities, and we conclude by suggesting that these contrasts in learnability may account for why human languages display non-adjacent regularities of one type much more widely than non-adjacent regularities of the other type.

Adult↗
PubMed1987

Spatial learning in the rat: impairment induced by the thiol-proteinase inhibitor, leupeptin, and an analysis of [3H]glutamate receptor binding in relation to learning.

Rats were given continuous intraventricular infusion of saline or the thiol-proteinase inhibitor leupeptin, via subcutaneously implanted osmotic minipumps, while being trained on a spatial learning water task using spaced trials. Leupeptin caused overnight forgetting during training, but performance eventually reached asymptote in both groups. A retention test conducted 48 h later to assess spatial memory revealed no significant group differences, but did cause, in saline-treated rats only, a disruption of subsequent retraining back to the correct spatial location. The groups showed no differences in Cl-dependent [3H]glutamate receptor binding to hippocampal or entorhinal cortex membranes subsequent to training. In a second experiment, normal rats trained on the same task also showed no differences in Cl-dependent [3H]glutamate binding relative to rats exposed to the water task but given random spatial position training and handled controls. The results are discussed in relation to the hypothesis of Lynch and Baudry (Science (1984) 224, 1057-1063) that a calcium-dependent thiol proteinase is involved in memory formation through its ability to modify glutamate receptor distribution and dendritic spine shape.

Animals↗
PubMed2003

An exploration of tutors' experiences of facilitating problem-based learning. Part 2--implications for the facilitation of problem based learning.

This paper is the second of two parts exploring a study that was undertaken to investigate the role of the tutor in facilitating problem-based learning (PBL). The first part focussed on the methodological underpinnings of the study. This paper aims to focus on the findings of the study and their implications for the facilitation of PBL. Six essential themes emerged from the findings that described the facilitation role. The tutors believed that their facilitation role was essentially structured around the decision of when to intervene and how to intervene in the PBL process. Modelling and non-verbal communication were seen as essential strategies for the facilitator. Underpinning these decisions was the need to trust in the philosophy of PBL. However, within many of the themes, there was a divergence of opinion as to how the role should actually be undertaken. Despite this, these findings have implications for the future role of PBL facilitators in Health Professional Education.

Attitude of Health Personnel↗