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At least 1,135 records · Page 63Linked to original sources
PubMed2005

Effect of intermittent exercise on multiple-choice reaction times of soccer players.

The influence of intermittent exercise on a choice-response time task was investigated. Two groups of 8 male soccer players (M age = 20.9, SD = 2.0) participated. They spent 4.4 (SD = 1.3) weekly hours on soccer training and had been playing soccer for 13 (SD = 3.3) years. Multiple-choice reaction speed and response accuracy were measured four times. Between measurements, one group performed 8-min. blocks of intermittent exercise on a bicycle ergometer and one group rested. Analysis showed that reaction speed and response accuracy were not significantly different between the two groups. Furthermore, there were significant faster reaction times and a larger number of correct reactions through Block 2 in both the exercise and control group (p < .05), probably a result of learning processes and familiarization with the task procedures. Further research towards the specific influence of mode of exercise, intensity, work-rest ratio and duration of intermittent exercise, and the sensitivity of reaction time tasks will be necessary to clarify the relationship between intermittent exercise and cognitive performance.

Adult↗
PubMed1996

No-scalpel technique for vasectomy.

This review aims to describe the development of the no-scalpel technique and to summarize the available results. An attempt is made to simplify the training of surgeons in the no-scalpel vasectomy technique. This technique uses the method described by Dr Li Shunqiang, utilizing a dedicated vas-grasping forceps; a sharp dedicated dissecting forceps, scissors and sutures are all that are required in addition. In a simple comparative study in Bangkok involving 1203 patients, it was found that the no-scalpel technique was faster. In the 19 cases of complications of symphysis and hemorrhage, 16 occurred using the standard technique (3.1 per 100 patients) and three from the no-scalpel technique (0.4 per 100 patients). The no-scalpel technique is probably more difficult to learn but requires fewer resources. The operation is nearly twice as fast as the standard technique with approximately one-eighth of its complications.

Clinical Competence↗
PubMedDate not supplied

Procedural learning in schizophrenia: further consideration on the deleterious effect of neuroleptics.

Deficits in procedural learning remain a controversial issue in schizophrenia. This may be related to the nature of the neuroleptic treatment of schizophrenic patients as conventional neuroleptics may be more deleterious than new atypical neuroleptics. However, there is no comparative study on the effect of specific neuroleptics on procedural learning. In this study, three groups of patients treated with different neuroleptics were compared to normal controls on two procedural learning tasks. In a visuo-motor task, patients and controls showed similar learning rates, although schizophrenic patients showed generally lower performances than normal controls. However, patients treated with a conventional neuroleptic, but not those treated with the atypical neuroleptics, showed many fluctuations during the initial learning phase. In a problem-solving task, all groups were comparable in performance and learning fluctuations, but learning rates were lower in patients treated with the neuroleptic showing the higher incidence of extrapyramidal symptoms. This suggests that procedural learning abilities may be significantly affected by neuroleptics in schizophrenia, although the effect may differ between tasks and the specific neuroleptics. Fluctuations in the initial learning phase of the visuo-motor task probably results from a frontal dysfunction while reduced learning rates, such as those observed in the problem solving task, may be attributed to a striatal dysfunction. This is concordant with the differential pharmacological actions of the conventional and atypical neuroleptics in these two cerebral areas.

Adult↗
PubMedDate not supplied

Physiological significance of long-term potentiation.

Long-term potentiation (LTP) is a form of synaptic plasticity that follows repetitive, high frequency stimulation of excitatory presynaptic fibers. It produces a long-lasting enhancement of synaptic strength that is usually revealed as an increased size of excitatory postsynaptic potentials. It is most prominent in the hippocampus, although it may be evoked in other brain regions. Use-dependent modifications in synaptic function are probably the basis of learning and memory, thus the study of LTP may represent a useful model for investigating the physiological mechanisms underlying the process of information storage.

Animals↗
PubMed1992

[Microcephalic children without mental retardation].

8 microcephalic children, mean age 3.06 years, with head circumferences -3.5 SD to -6 SD, achieved IQ scores of 79-115 on the Thermann, WPPSI, WISC-R, and/or Columbia tests. They had no dysmorphic features nor congenital anomalies, and their fundi were normal. 7 had congenital microcephaly, associated with proven autosomal dominant heritage in 3, 1 had suspected autosomal recessive heritage, 1 had intrauterine growth retardation (overall smallness), 1 had cerebral palsy, and in 1 there was an unknown prenatal cause. 6 of these children had 1 or 2 developmental disabilities, including neurosensory deafness, cerebral palsy, short attention span, perceptual dysfunctions, and learning disability. Microcephaly, most probably secondary to malnutrition in early infancy, was diagnosed in 1 child without developmental disabilities. However, our data support the concept that some microcephalic children with significantly small head circumference, who function without mental retardation, have a high incidence of other developmental disabilities.

Child↗
PubMed1984

[Individual characteristics of the behavior, learning and adaptation of rats exposed to extreme conditions].

Techniques of open field, instrumental food conditioning and acute hypoxic hypoxia were used in experiments on white rats which had been divided into three groups: low--(I), middle--(II) and high-entropy (III). The III group rats were characterized by high motor activity, various postures and states which seemed to account for fast instrumental conditioning of these rats. Rats of the II and III groups (67% of all the rats) proved most resistant against hypoxia and therefore more adaptable to extreme factors.

Acute Disease↗
PubMed1997

[Insulin therapy in type II diabetes].

The results of conventional intensified insulin therapy (4 injections per day) in type II diabetics correspond more to those of conventional therapy (2 injections per day). Compared to a conventionally treated collective with strict dietetic regimen the intensified treated type II diabetics did not lead to an improved metabolic control. The frequency of hypoglycemic episodes did not differ in both collectives. Intensified insulin therapy is associated with subjectively increased comfort and increased life quality despite the seldom use of the advantages of the therapy. The management of the intensified therapy probably has to be learned in an earlier stage of life and requires repeated and more intensified education in elderly patients. The regression of typical late complications of diabetes mellitus as seen in the DCCT may possibly be achieved by a greater effort in therapy and empowerment of the patient.

Aged↗
PubMed1993

Neural networks, nativism, and the plausibility of constructivism.

Recent interest in PDP (parallel distributed processing) models is due in part to the widely held belief that they challenge many of the assumptions of classical cognitive science. In the domain of language acquisition, for example, there has been much interest in the claim that PDP models might undermine nativism. Related arguments based on PDP learning have also been given against Fodor's anti-constructivist position--a position that has contributed to the widespread dismissal of constructivism. A limitation of many of the claims regarding PDP learning, however, is that the principles underlying this learning have not been rigorously characterized. In this paper, I examine PDP models from within the framework of Valiant's PAC (probably approximately correct) model of learning, now the dominant model in machine learning, and which applies naturally to neural network learning. From this perspective, I evaluate the implications of PDP models for nativism and Fodor's influential anti-constructivist position. In particular, I demonstrate that, contrary to a number of claims, PDP models are nativist in a robust sense. I also demonstrate that PDP models actually serve as a good illustration of Fodor's anti-constructivist position. While these results may at first suggest that neural network models in general are incapable of the sort of concept acquisition that is required to refute Fodor's anti-constructivist position, I suggest that there is an alternative form of neural network learning that demonstrates the plausibility of constructivism. This alternative form of learning is a natural interpretation of the constructivist position in terms of neural network learning, as it employs learning algorithms that incorporate the addition of structure in addition to weight modification schemes. By demonstrating that there is a natural and plausible interpretation of constructivism in terms of neural network learning, the position that nativism is the only plausible model of acquisition can no longer be defended. Indeed, I briefly discuss a number of learning-theoretic reasons indicating that constructivist models so characterized uniquely possess a number of important learning characteristics.

Cognition↗
PubMed1999

[Evaluation of factors affecting early and late outcome of 225 kidney transplantations].

The aim of this study was to evaluate some chosen factors affecting early and late outcome of 225 renal transplantations performed in the Department of General and Transplantation Surgery of the Pomeranian Medical Academy in Szczecin from 1985 to 1995. Analysed groups were elected from this number in a way as to be comparable and their demographic data were discussed. Factors taken into consideration were: the impact of transplantation team experience, operator, graft perfusion method, preservation solution, multiple renal arteries, uretheral stent, multiorgan harvesting and donor sex. The early outcome was estimated as: immediate function, delayed function and nonfunction. The late outcome was: 3 months, 1 year and 3 years graft and patient survival. Analysed groups were compared as far as an incidence of following surgical postoperative complications: urological, vascular, septic, graft rupture, bleeding, fluid collections and other surgical complications, is concerned. The data base was statistically elaborated using t-Student and Chi 2 test taking as statistically significant p less than 0.05. Results show that the impact of transplantation team experience was an important factor (Tab. 1, 2, 3). The comparison of three following groups of transplantations (75 cases each) elucidates that after learning period came a stabilisation period, in which the outcome is close to that achieved in other Polish transplantation centers. While investigating the factor of operator two groups of transplantations performed by seniors and one "learning group" were compared and no statistically significant difference was found. This is probably because each transplantation done by learning surgeon was assisted by one of above seniors. The perfusion method impact was investigated comparing two small groups (in situ and ex situ perfusion) and no benefit of any was proved. The difference between outcomes of groups in which UW or Eurocollins was used, was statistically significant as far as three years graft survival is concerned. In UW group it was 55.9%, whereas in Eurocollins group it was 29.4%. The probable explanation is that the possibility of longer cold ischemia time, given by UW solution, implicates more time to find better suited recipient for particular graft. The impact of multiple renal arteries on the outcome of transplantation was analysed by comparing group of 105 grafts with one artery and 25 multiple arterias grafts. The immediate function occurred in 92% of group with multiple and 62.9% of group with one artery. The difference was statistically significant. The factor of indwelling uretheral stent was investigated comparing the group of 94 transplantations where it was used and the group of 35 transplantations without it. There was no difference as far as urological complications are concerned. Multiorgan harvesting plays a very important role facing serious organ shortage in all developed countries. The comparison of 37 multiorgan and 95 kidney harvestings showed no negative implications of the first one for the outcome of renal transplantations. Evaluation of donor sex factor did not show any essential differences while comparing group of 162 grafts taken from male and the group of 63 grafts taken from female donors. Following conclusions were established after discussion of above results: the most important factor was the impact of transplantation team experience; preservation by UW solution caused better late outcome of treatment; there was no negative influence of transplanting grafts with multiple arteries; the impact of operator, donor sex, perfusion method, multiorgan donation and use of uretheral stent was not proved.

Evaluation Studies as Topic↗
PubMed2006

Anatomy of a decision: striato-orbitofrontal interactions in reinforcement learning, decision making, and reversal.

The authors explore the division of labor between the basal ganglia-dopamine (BG-DA) system and the orbitofrontal cortex (OFC) in decision making. They show that a primitive neural network model of the BG-DA system slowly learns to make decisions on the basis of the relative probability of rewards but is not as sensitive to (a) recency or (b) the value of specific rewards. An augmented model that explores BG-OFC interactions is more successful at estimating the true expected value of decisions and is faster at switching behavior when reinforcement contingencies change. In the augmented model, OFC areas exert top-down control on the BG and premotor areas by representing reinforcement magnitudes in working memory. The model successfully captures patterns of behavior resulting from OFC damage in decision making, reversal learning, and devaluation paradigms and makes additional predictions for the underlying source of these deficits.

Animals↗
PubMed1964

ATTITUDE STATEMENTS AS POSITIVE AND NEGATIVE REINFORCEMENTS.

The finding that attraction is a function of attitude similarity has been interpreted as a special case of the effect of positive and negative reinforcements on attraction. A simple discrimination learning task was employed in which the reinforcements were attitude statements similar and dissimilar to the opinions of the subject. The presentation of similar attitude statements after each correct response and dissimilar attitude statements after each incorrect response significantly changed response probability. The hypothesis that such statements could be used as reinforcers in a learning situation was thus confirmed.

Attitude↗
PubMed1978

T-maze shock avoidance in the hermit crab Dardanus arrosor.

Specimens of the hermit crab Dardanus arrosor go indistinctively towards any of the arms of a T-maze if lighting is uniform. The difference between the probabilities of going towards one arm rather than the other tends to zero as the number of trials is increased. If only one of the arms is lightened, hermits go preferably towards the dark one: The difference between the two probabilities tends to 0.500. If the animals attracted by the dark zone are electroshocked (60 V, 2.5 seconds) near their oral zone, the probability of going towards the light zone increases (statistically significant). Differences between the learning abilities of both sexes are not significant.

Animals↗