SEARCH · PubMed Health

Results for “GENERALIZATION 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 739 records · Page 41Linked to original sources

PubMed1971

Auditory generalization gradients for response latency in the monkey.

Two monkeys were trained to press and hold a response key in the presence of a light and to release it at the onset of a pure tone. Initially, all responses with latencies shorter than 1 sec were reinforced without regard to the frequency of the pure tone, and the intensity of the pure tone that resulted in equal latencies at each frequency was determined. The second stage of the experiment consisted of discrimination training, during which releases to one pure-tone frequency (positive stimulus) were reinforced and releases to a second frequency (negative stimulus) were extinguished. Median latencies to the negative stimulus slowly increased as did the variability of the latency distribution for the negative stimulus. There was no evidence of a concurrent decrease in latencies to the positive stimulus indicative of behavioral contrast. The third part of the experiment consisted of determining maintained generalization gradients by increasing the number of nonreinforcement stimuli. The gradients that eventually resulted showed approximately equal latencies to all frequencies of the negative stimulus and shorter latencies to the positive stimulus frequency.

Animals↗

PubMed2002

Incremental training increases the plasticity of the auditory space map in adult barn owls.

The plasticity in the central nervous system that underlies learning is generally more restricted in adults than in young animals. In one well-studied example, the auditory localization pathway has been shown to be far more limited in its capacity to adjust to abnormal experience in adult than in juvenile barn owls. Plasticity in this pathway has been induced by exposing owls to prismatic spectacles that cause a large, horizontal shift of the visual field. With prisms, juveniles learn new associations between auditory cues, such as interaural time difference (ITD), and locations in visual space, and acquire new neurophysiological maps of ITD in the optic tectum, whereas adults do neither. Here we show that when the prismatic shift is experienced in small increments, maps of ITD in adults do change adaptively. Once established through incremental training, new ITD maps can be reacquired with a single large prismatic shift. Our results show that there is a substantially greater capacity for plasticity in adults than was previously recognized and highlight a principled strategy for tapping this capacity that could be applied in other areas of the adult central nervous system.

Acoustic Stimulation↗

PubMed1977

Drug-related syndromes in clinical nephrology.

The major clinical presentations of disease to a nephrologist can be grouped into six general areas: acute renal failure, chronic renal failure, nephrotic syndrome, fluid-electrolyte disorders, acid-base disturbances, and the uremic symptom-complex. Each of these major clinical syndromes can be caused by, or related to, drugs or environmental toxins. Prototype drugs can be used to highlight the features of each drug-related syndrome. Although it is preventable, drug-related disease may present opportunities to learn about general pathophysiologic mechanisms in clinical nephrology.

Acute Kidney Injury↗

PubMedDate not supplied

Multiple motor learning experiences enhance motor adaptability.

Traditional motor learning theory emphasizes that skill learning is specific to the context and task performed. Recent data suggest, however, that subjects exposed to a variety of motor learning paradigms may be able to acquire general, transferable knowledge about skill learning processes. I tested this idea by having subjects learn five different motor tasks, three that were similar to each other and two that were not related. A group of experimental subjects first performed a joystick-aiming task requiring adaptation to three different visuomotor rotations, with a return to the null conditions between each exposure. They then performed the same joystick-aiming task but had to adapt to a change in display gain instead of rotation. Lastly, the subjects used the joystick-aiming task to learn a repeating sequence of movements. Two groups of control subjects performed the same number of trials, but learned only the gain change or the movement sequence. Experimental subjects showed generalization of learning across the three visuomotor rotations. Experimental subjects also exhibited transfer of learning ability to the gain change and the movement sequence, resulting in faster learning than that seen in the control subjects. However, transient perturbations affected the movements of the experimental subjects to a greater extent than those of the control subjects. These data demonstrate that humans can acquire a general enhancement in motor skill learning capacity through experience, but it comes with a cost. Although movement becomes more adaptable following multiple learning experiences, it also becomes less stable to external perturbation.

Adaptation, Physiological↗

PubMed1967

Stimulus generalization as signal detection in pigeons.

Pigeons that were reinforced for pecking at a single-wavelength responded to nearby wavelengths with lower rates. Response rates indicated the pigeons' certainty that the reinforced stimulus was present. The ratings yielded receiver operating characteristic functions that approximated straight lines on a double probability plot.

Animals↗

PubMed1968

Further evidence of a sensory-tonic interaction in pigeons.

The five pigeons in Group 1 were given successive intradimensional discrimination training in which responses to a line of 49 degrees were reinforced on a variable-interval schedule and responses to a line of 33 degrees were not reinforced. Subsequent generalization testing with other line orientations revealed a peak shift from the positive stimulus in the direction away from the negative stimulus in all subjects. The four pigeons in Group 2 received successive discrimination training with the 49 degrees value on the key during both stimuli. During the negative stimulus, however, the floor was tilted 16 degrees counterclockwise. When tested (with the floor flat) these subjects showed peak shifts similar to those observed with Group 1. A third group of three pigeons, given successive interdimensional discrimination training with the 49 degrees line as the positive stimulus and the absence of the line as the negative, showed no peak shift in a subsequent generalization test. It was concluded that tilting the floor on which the pigeon stood systematically distorted the bird's visual perception of the orientation of the line in a manner consistent with the results of other studies in this laboratory.

Animals↗

PubMed1971

Apparent movement and real movement detection in the pigeon: stimulus generalization.

Pigeons were trained to discriminate apparent movement and real movement in visual displays showing horizontal movement. Generalization testing on the dimension of directional movement yielded gradients that sloped as movement changed from horizontal to vertical. Evidence of generalization between apparent movement and real movement was found in equivalent response rates to training displays of either type. Extremely low response rates to training displays pulsating but showing no movement eliminated flicker as the basis of the discrimination.

Animals↗

PubMed2003

Effect of service-learning on knowledge about older people and faculty teaching evaluations in a physical therapy class.

The major purpose of this study was to identify the knowledge, misconceptions, and bias regarding aging among graduate physical therapy students and to determine whether service-learning modified any of these variables. A cohort of 40 students in a graduate physical therapy program was randomly divided into an experimental (service-learning) or control (no service-learning) group. General knowledge and attitudes about aging were measured by Palmore's Facts on Aging Quiz I. The Wilson Student Evaluation of Faculty tool measured student evaluations of a faculty member at the end of the semester. Two-way analyses of variance with repeated measures revealed that all students increased their knowledge about aging, p < .05. However, students who initially had negative attitudes toward older adults significantly improved their attitudes only after the service-learning experience, p < .05. A t-test revealed that teaching evaluation scores were significantly lower in the service-learning course, p < .05. The results suggest that service-learning effectively enhanced both the knowledge and attitudes of physical therapy students toward the older adult. Although service-learning imparted better learning for the student, there was some risk to the faculty member as evidenced by lower teaching evaluations.

Adult↗

PubMed2001

Evaluation of problem-based learning: a lecturer's perspective.

INTRODUCTION: The exponential growth in medical/dental knowledge and the ever-expanding influence and sophistication of information technologies have placed a burden of responsibilities on dental educators to fashion out a curriculum that can prepare students to face the coming challenges in the new millennium. Consequently, a curriculum reform took place in the Faculty of Dentistry, National University of Singapore in 1997. Problem-based learning (PBL) was first introduced to the Faculty in 1996 as a pilot project to the 4th year. The purpose of this project was to evaluate the 4-year experience in PBL teaching and learning from the lecturers' point of view. MATERIALS AND METHODS: All 12 lecturers, who had been involved in the PBL teaching, participated in this questionnaire survey, which was composed of 17 questions with a 5-digit Likert scale. Data analysis was carried out using the Spearman's correlation, t-test, and the Mann-Whitney U test. RESULTS: Six female, 5 male and 1 unidentified lecturers were recruited into this survey with a 100% response rate. In general, lecturers learned more in teaching PBL and significantly took pleasure in the interactive learning and self-directed learning modes inherent to PBL (P = 0.004). Compared to the male lecturers, female lecturers had a greater propensity to feel that PBL teaching might not be cost-effective (P = 0.03). Senior lecturers felt more fulfilled compared with the younger ones (P = 0.026). Those lecturers who enjoyed the interactive learning experience in PBL seemed to like the self-directed learning and felt more fulfilled through teaching PBL compared to the traditional teaching (TT) (P < 0.01). They also felt that PBL may be cost-effective (P < 0.01). Lecturers did not have difficulties in being a facilitator (P = 0.04). Interestingly, lecturers who found difficulties in being a facilitator for the PBL class seemed to learn more in teaching PBL classes than in TT (P < 0.05). Overall, lecturers would like to suggest more PBL to be incorporated into the curriculum (P = 0.02). Nevertheless, lecturers were concerned about the knowledge gaps in students learning with PBL (P = 0.01) and the time constraint of students (P = 0.002). CONCLUSION: The results of this study reveal the pros and cons of the current PBL teaching method and may thus provide proper guidelines to shape the further development of PBL in our faculty.

Age Factors↗

PubMed1992

Generalization peak shift for autoshaped and operant key pecks.

Pigeons acquired discriminated key pecking between 528- and 540-nm stimuli by either a response-reinforcer (operant group) or a stimulus-reinforcer (autoshaped group) contingency, with other training-schedule parameters comparable over groups. For the birds in the operant group, key pecks intermittently produced grain in the presence of one hue on the key (positive stimulus) but not in the other (negative stimulus). For the birds in the autoshaped group, pecking emerged when grain was intermittently presented independently of key pecking during one key color but was not presented during the other key color. Two independent contingency assays, peck-location comparisons and elimination of differences in reinforcement rate, confirmed the effectiveness of the two training procedures in establishing operant or respondent control of key pecking. After reaching a 10:1, or better, discrimination ratio between key pecks during the two key colors, the birds received a wavelength generalization test. Criterion baseline key-peck rates were comparable for operant and autoshaped groups prior to testing. On the generalization test, performed in extinction, all birds pecked most at a stimulus removed from the positive training stimulus in the direction away from the negative stimulus. In testing, autoshaped "peak" rates (24.5 to 64.9 pecks per minute) were from 33% to 80% higher than rates in the presence of the training stimuli. Respondent peak shift rarely has been reported heretofore, and never this consistently and robustly. These results further confirm the similarity of perceptual processing in classical and operant learning. They are discussed in terms of Spence's gradient-interaction theory and Weiss' (1978) two-process model of stimulus control.

Animals↗

PubMed2003

Effects of learning on smooth pursuit during transient disappearance of a visual target.

Previous research has demonstrated learning in the pursuit system, but it is unclear whether these effects are the result of changes in visual or motor processing. The ability to maintain smooth pursuit during the transient disappearance of a visual target provides a way to assess pursuit properties in the absence of visual inputs. To study the long-term effects of learning on nonvisual signals for pursuit, we used an operant conditioning procedure. By providing a reinforcing auditory stimulus during periods of accurate tracking, we increased the pursuit velocity gain during target blanking from 0.59 in the baseline session to 0.89 after 8 to 10 daily sessions of training. Learning also reduced the occurrence of saccades. The learned effects generalized to untrained target velocities and persisted in the presence of a textured visual background. In a yoked-control group, the reinforcer was independent of the subjects' responses, and the velocity gain remained unchanged (from 0.6 to 0.63, respectively, before and after training). In a control group that received no reinforcer, gain increased slightly after repetition of the task (from 0.63 to 0.71, respectively, before and after training). Using a model of pursuit, we show that these effects of learning can be simulated by modifying the gain of an extra-retinal signal. Our results demonstrate that learned contingencies can increase eye velocity in the absence of visual signals and support the view that pursuit is regulated by extra-retinal signals that can undergo long-term plasticity.

Acoustic Stimulation↗

PubMed2005

Auditory frequency discrimination learning is affected by stimulus variability.

We explored the effects of training set variability on learning and generalization of pure-tone frequency discrimination (FD) in three groups of untrained, normally hearing adult listeners. Group 1 trained using a fixed standard tone at 1 kHz (fixed), Group 2 on slightly varying (roving) tones around 1 kHz, and Group 3 on widely varying standard frequencies (wide-roving). Initially, two thirds of all listeners had low FD thresholds (good listeners) and one third had intermediate to high thresholds (poor listeners). For good listeners, slight variations in the training set slowed learning but wide variations did not. Transfer to untrained frequencies (up to 4 kHz) and to the fixed condition was equivalent regardless of training condition, but Group 1 listeners did not fully transfer learning to the roving condition. For poor listeners, any variation in the training condition slowed learning and impaired transfer to other frequencies but did not affect transfer to untrained conditions. Thus, the effects of training set on progress and outcome depend on set variability and individual FD ability.

Adult↗

PubMed1981

Investigations on the CNS sites of action of the discriminative stimulus effects of arecoline and nicotine.

The role of the dorsal hippocampus (DH) and mesencephalic reticular formation (MRF) in mediating the discriminative stimulus (DS) effects of nicotine and arecoline was assessed. In rats trained to discriminate nicotine (1.14 mg/kg) from saline, peripherally administered nicotine generalized to injection of nicotine, but not arecoline, directly into the DH and MRF. The stimulus effect of centrally administered nicotine was antagonized by peripherally administered mecamylamine, but not atropine. Response rate decreases were also observed after nicotine injection into either site. In rats trained to discriminate arecoline (1.74 mg/kg) from saline, peripherally administered arecoline did not generalize to the direct injection of arecoline into the DH and MRF. However, a decrease in response rates was observed after arecoline injection into either site. Thus, The DH and MRF are important in mediating the DS effect of nicotine but not arecoline.

Animals↗

PubMed1996

Detection of seizure activity in EEG by an artificial neural network: a preliminary study.

Neural networks, inspired by the organizational principles of the human brain, have recently been used in various fields of application such as pattern recognition, identification, classification, speech, vision, signal processing, and control systems. In this study, a two-layered neural network has been trained for the recognition of temporal patterns of the electroencephalogram (EEG). This network is called a Learning Vector Quantization (LVQ) neural network since it learns the characteristics of the signal presented to it as a vector. The first layer is a competitive layer which learns to classify the input vectors. The second, linear, layer transforms the output of the competitive layer to target classes defined by the user. We have tested and evaluated the LVQ network. The network successfully detects epileptiform discharges (EDs) when trained using EEG records scored by a neurologist. Epochs of EEG containing EDs from one subject have been used for training the network, and EEGs of other subjects have been used for testing the network. The results demonstrate that the LVQ detector can generalize the learning to previously "unseen" records of subjects. This study shows that the LVQ network offers a practical solution for ED detection which is easily adjusted to an individual neurologist's style and is as sensitive and specific as an expert visual analysis.

Adolescent↗

PubMed2004

Spermidine/spermine N1-acetyltransferase overexpression in mice induces hypoactivity and spatial learning impairment.

The present work addresses the role of polyamines in learning and general behavior by subjecting transgenic mice overexpressing polyamine catabolic enzyme, spermidine/spermine N(1)-acetyltransferase (SSAT) and their syngenic littermates to neurobehavioral profiling assessment (SHIRPA) and to radial eight-arm maze. The general health and physiological conditions as well as the entire behavioral battery comprising of 34 parameters were recorded. The eight-arm radial maze (8-RAM) task included an initial acquisition task for 9 days followed by a 2-day retention test after a 2-week break. In addition, blood samples were taken for hormone analysis. Transgenic mice, which showed reduced motor activity, aggression and muscle tone, spent more time in the radial maze during initial acquisition and retention tasks as compared with syngenic mice. Moreover, the learning performance of transgenic females was significantly inferior to syngenic females. Interestingly, the levels of several hormones were significantly altered in SSAT transgenic mice; circulating adrenocorticotropic hormone (ACTH) and corticosterone levels were markedly increased while testosterone and thyroidal hormone levels were decreased. These changes may be related to the dramatic increase in brain putrescine levels in SSAT-overexpressing (SSAT-OE) mice, but it is likewise possible that the behavioral changes and learning impairment are attributable to more peripheral mechanisms (such as alterations in steroid hormone metabolism), which in turn, could be a consequence of the disturbed polyamine homeostasis.

Acetyltransferases↗

PubMedDate not supplied

[Evaluation of the effect of the health education intervention project "Healthy School"].

UNLABELLED: Contemporary health-education intervention programs are increasingly used as a tool for improving health of school children [1-4]. Since 1992 a Network of 13 elementary Health Promoting Schools established in Yugoslavia (though not yet admitted to the European Network) has been operational. The Project was approved by the Ministries of Health, Education and Ecology from the very beginning, and financially supported by the Government of Serbia since 1995. The team of up to 40 health professionals, school principals and school project managers worked together for four years to change the working conditions in schools knowledge, attitudes and behaviour of school children and staff in order to improve their health [5]. The goal of this paper is to present results of health education intervention in changing of hygienic conditions in schools, as well as some of the attitudes, behaviour and knowledge of pupils and their parents. METHOD: The study took place before and after the intervention--at two points in time--during 1993 and 1996. The tri-angular approach including (1) pupils, (2) schools (teachers, school environment), and (3) parents, was used. A random pretest and post-test study design with control group (12 experimental and two control schools) has been implemented. The multiphase cluster sample was employed in order to represent all of the country typical regions. Six types of especially designed questionnaires were used to provide comparable variables in the sample of pupils, their parents and teachers. Exception were 1st-graders and 4th-graders for whom information were gathered by means of a "draw-and-write" investigation technique [6]. The response rate was 88.70% before and 98.28% after intervention. Data were analyzed by descriptive and inferential statistics using SPSS/PC software. RESULTS: Schools are somewhat less overcrowded, much cleaner and better maintained after the four-year intervention. Toilets are in a better condition, but there is still much more to be done. The 1st- and 4th-graders, surveyed by the draw-and-write method, mentioned numerous ways of keeping and improving health, which were summarized as fifteen health-improvement measures (Graph 1). The most frequently mentioned measures were nutrition, physical activity, general hygiene, oral and dental hygiene, sleeping and fresh air. Each of these measures was mentioned by over 20% of the surveyed pupils. Eleven of 15 variables showed significant increase in frequencies (at the level of at least p < 0.01) after the intervention. As an indicator of a nutrition behaviour, the regularity of main meals is analyzed (Graph 2). The majority of children eat regularly and the difference before and after intervention is significant only for the school meal (c2 = 30.715, p < 0.001). Although over 70% of children learn that general hygiene is good for health in junior graders, only about little more than 30% of senior graders have a bath or shower every day, while others only once or twice a week. The differences are significant before and after the intervention (c2 = 10.648, p < 0.05) only for everyday practice. More than 90% of senior-grade pupils brush their teeth at least once or several times a day. Over 60% of children in our survey go in for sport, whereas about 20% never do so. It seems that the intervention contributed symbolically to this practice important for health, though before-after difference is significant (c2 = 6.673, p < 0.05). However, in the control group schools children have much less physical activity in 1996, and this difference is significant (c2 = 14.070, p < 0.010). The psycho-emotional status of Yugoslav young people is strongly influenced by the situation in the country the war, the economic disaster and the impact of international sanctions. Consequently, more than one-fourth of the children complained of frequent exhaustion and concentration problems, which their parents also noticed. (ABSTRACT TRUNCATED)

Child↗

PubMed2003

Episodic memory in schizophrenic patients and their relatives.

BACKGROUND: Memory dysfunction among healthy relatives of patients with schizophrenia suggests that genetic liability to the disorder can also be manifested as cognitive impairment. This study was designed to further elucidate the nature of the memory dysfunction being transmitted. METHOD: Memory function was assessed in 62 schizophrenic patients, 98 of their healthy relatives and 66 controls. Material-specific immediate/delayed recall and percentage retention were investigated using the Logical Memory and Visual Reproduction tests of the Wechsler Memory Scale (WMS). A third subtest of the WMS, the Associate Learning and a visual analogue of it, the Abstract Paired Associates, were used to measure verbal and visual learning. Current general intellectual function was assessed using a five-subtest short-form of the Wechsler Adult Intelligence scale-Revised (WAIS-R). RESULTS: Schizophrenic patients performed significantly worse than controls on nearly all measures. Their relatives also showed significant deficit on the immediate and delayed recall of the Logical Memory, immediate recall of the Visual Reproduction, and the Abstract Paired Associates tests. Logical memory was substantially more impaired than the other measures for both patients and relatives. The deficit in immediate recall of the Logical Memory remained significant even after excluding those relatives with an Axis I diagnosis and schizotypal personality disorder. These findings were despite the relatives having an equivalent level of general intellectual function to that of controls. CONCLUSION: Familial, presumed genetic, liability to schizophrenia may be expressed as dysfunction in verbal memory.

Adolescent↗

PubMed1985

The quantal nature of controlling stimulus-response relations as measured in tests of stimulus generalization.

This paper is a selective review of research that addresses the validity of two interpretations of stimulus generalization. One interpretation, referred to as the descriptive stimulus-control interpretation, proposes that during stimulus generalization a continuous relation exists between stimulus and response dimensions. The other interpretation, referred to as the quantal interpretation, proposes that a stimulus-response relation functions as a unit that may or may not occur. From the latter viewpoint, the continuity typically obtained during generalization tests is deemed to be artifactual and to result from averaging across multiple controlling stimulus-response relations. Studies examining the contribution of these multiple relations to generalization gradients are reviewed. With few exceptions, the quantal interpretation appears to better characterize the results of these studies. Implications for peak shift, selection of analytical level, and identification of the behavioral unit are discussed, as well as factors that may determine the acceptability of the quantal interpretation.

Animals↗