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At least 1,747 records · Page 97Linked to original sources
PubMed2005

Instrumental learning, but not performance, requires dopamine D1-receptor activation in the amygdala.

Substantial experimental evidence exists suggesting a critical role for dopamine in reinforcer-related processes, such as learning and drug addiction. Dopamine receptors, and in particular D1 receptors, are widely considered as modulators of synaptic plasticity. The amygdala contains both dopamine terminals and dopamine D1 receptors and is intimately involved in motivation and learning. However, little is known about the involvement of D1 receptor activation in two subnuclei of the mammalian amygdala, the central nucleus and basolateral complex in instrumental learning. Following recovery from surgery and preliminary training, rats with bilateral indwelling cannulae aimed at the central nucleus or basolateral complex were trained to lever-press for sucrose pellets over 12 sessions. Infusion of the selective D1 antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (0.3 nmol and 3.0 nmol) prior to the first five training sessions dose-dependently impaired instrumental learning when compared with vehicle-infused controls. All rats were then exposed to five sessions drug-free; lever-pressing quickly reached equal levels across groups. A drug infusion prior to an 11th session revealed no effect on performance. Control experiments indicated that basic motivational processes and general motor responses were intact, such as spontaneous feeding and locomotor activity. These results show an essential role for D1-receptor activation in both the central nucleus and basolateral complex on the acquisition of lever pressing for sucrose pellets in rats, but not the performance of the behavior once conditioned. We propose that instrumental learning is dependent on plasticity in the central nucleus and basolateral complex amygdala, and that D1 receptor activation participates in transcriptional processes that underlie this plasticity.

Amygdala↗
PubMed2007

Classical reward conditioning in Drosophila melanogaster.

Negatively reinforced olfactory conditioning has been widely employed to identify learning and memory genes, signal transduction pathways and neural circuitry in Drosophila. To delineate the molecular and cellular processes underlying reward-mediated learning and memory, we developed a novel assay system for positively reinforced olfactory conditioning. In this assay, flies were involuntarily exposed to the appetitive unconditioned stimulus sucrose along with a conditioned stimulus odour during training and their preference for the odour previously associated with sucrose was measured to assess learning and memory capacities. After one training session, wild-type Canton S flies displayed reliable performance, which was enhanced after two training cycles with 1-min or 15-min inter-training intervals. Higher performance scores were also obtained with increasing sucrose concentration. Memory in Canton S flies decayed slowly when measured at 30 min, 1 h and 3 h after training; whereas, it had declined significantly at 6 h and 12 h post-training. When learning mutant t beta h flies, which are deficient in octopamine, were challenged, they exhibited poor performance, validating the utility of this assay. As the Drosophila model offers vast genetic and transgenic resources, the new appetitive conditioning described here provides a useful tool with which to elucidate the molecular and cellular underpinnings of reward learning and memory. Similar to negatively reinforced conditioning, this reward conditioning represents classical olfactory conditioning. Thus, comparative analyses of learning and memory mutants in two assays may help identify the molecular and cellular components that are specific to the unconditioned stimulus information used in conditioning.

Animals↗
PubMed1983

Matching and maximizing with concurrent ratio-interval schedules.

Animals exposed to standard concurrent variable-ratio variable-interval schedules could maximize overall reinforcement rate if, in responding, they showed a strong response bias toward the variable-ratio schedule. Tests with the standard schedules have failed to find such a bias and have been widely cited as evidence against maximization as an explanation of animal choice behavior. However, those experiments were confounded in that the value of leisure (behavior other than the instrumental response) partially offsets the value of reinforcement. The present experiment provides another such test using a concurrent procedure in which the confounding effects of leisure were mostly eliminated while the critical aspects of the concurrent variable-ratio variable-interval contingency were maintained: Responding in one component advanced only its ratio schedule while responding in the other component advanced both ratio schedules. The bias toward the latter component predicted by maximization theory was found.

Animals↗
PubMed2004

The challenges of residents teaching neurology.

BACKGROUND: Teaching is integrated into the daily practice of residents, and it is a skill necessary for practice as well as academics. The settings in which teaching and learning take place are ubiquitous but include classrooms, small groups, bedside rounds, and grand rounds. Given the learning environment of residency, neurology residents should have working knowledge of basic principles of effective teaching to make learning successful. Teaching also reinforces knowledge, and residents will likely be better practitioners if some basic skills of teaching are practiced. REVIEW SUMMARY: Neurology teaching techniques for residents are rarely addressed in the medical literature. Although information regarding teaching principles in medicine exists, there is little information regarding how residents teach. We examine and review some of the more effective methods and appreciated qualities in teachers, with a particular emphasis for the neurology resident. We also review whom neurologists need to teach and the various settings in which teaching may take place. CONCLUSIONS: Neurology residents encounter a variety of audiences in a variety of settings that require diverse teaching skills to effectively convey information to other providers as well as patients. The majority of these skills should be learned in residency to establish a foundation for teaching, regardless of future practice settings.

Clinical Competence↗
PubMed2004

Why cooperate? An economic perspective is not enough.

Cooperation is usually explained from an economic perspective focused mainly on the tangible outcomes received by individuals that are also dependent on the behavior of others, with little reference to the actual behaviors used when cooperating. The potential consequences of social dimensions associated with cooperative behaviors are minimized in Skinnerian and game-theory models by means of anonymous subjects that behave individually while physically isolated in separate chambers. When cooperation and non-cooperation occur in the real world, however, they are often associated not only with different outcomes but also with different behaviors. Unlike non-cooperation, cooperative behaviors are usually intrinsically social, influenced by the presence and behaviors of familiar partners. Research is described that addresses whether the social dimensions of cooperative actions go beyond mere description of behaviors to also explain why cooperation occurs. One way to resolve the relative importance of economic and social factors for explanations of cooperation is to measure choice between the options of cooperation and non-cooperation. The economic perspective, linked to models derived from game theory, frames the question as a choice determined by differences in tangible outcomes such as food or money that, in evolutionary terms, are surrogates for gains in fitness. From a behavioral perspective, the choice between cooperation and non-cooperation is also determined by social dimensions associated only with cooperation. The influence of social cooperation on preference was examined by means of two rectangular chambers interconnected by a T-maze. In one chamber, pairs of laboratory rats were reinforced with saccharin solution for coordinating back-and-forth shuttling; in the second chamber, a single animal was reinforced for back-and-forth shuttling performed in isolation. With outcomes equalized between the two options, cooperation was preferred by the majority of subjects. Moreover, variation in the relative rate of reinforcement during cooperation was not a strong predictor of choice whereas the level of intra-pair coordination was positively related to preference. Implications of this result are discussed for both method and theory, including the hypothesis that the preference is influenced by intrinsic reinforcements evoked by cooperating. The consequences for evolutionary fitness would then arise not only from tangible outcomes but from the relationships that develop when cooperating even when immediate and tangible pay-offs are absent, insufficient or sub-optimal. The impact of cooperative relationships on fitness may therefore not occur immediately but in the future, and perhaps in another context, when they influence outcomes that have a significant impact on survival and reproduction.

Animals↗
PubMed1998

Setting generalization of question-asking by children with autism.

We examined whether motivational procedures incorporated into teaching question-asking to children with autism, who lack verbal initiations, would result in generalization without additional teaching, prompting, or reinforcement in other settings. Specifically, we assessed whether such children could learn to use questions and whether the spontaneous use of question-asking would generalize across stimuli, settings, and people. All children learned to use questions in relation to items they had previously been unable to label and demonstrated generalization of spontaneous question-asking to new items and to their home environments with their mothers, with concomitant gains in expressive vocabulary. Results were discussed in terms of teaching response strategies, such as question-asking, to promote spontaneous child-initiated social interactions and expressive language development.

Autistic Disorder↗
PubMed1982

The health belief model and nutrition education.

Five axioms of learning explain the stability of dietary practices and suggest approaches to teaching more healthful habits. These axioms include the influence of prior beliefs and attitudes upon people's interpretations, the fact that effective learning is incremental, the value of reinforcement, the habitual nature of much behavior, and the fact that learning includes both cognitions and skills. The Health Belief Model (HBM), a specification of the first axiom, holds that people are likely to follow health recommendations if they are motivated about their health and if they believe that they are susceptible to an ill health condition; that the occurrence of that condition would have serious impact on their lives; that following a particular set of health recommendations would be beneficial in reducing either their susceptibility to or the severity of the condition; and that the psychological benefits of following the health recommendation outweighs its costs. Educational diagnosis may be made by identifying peoples' status on each variable in the HBM and then formulating an educational plan directed toward modifying beliefs, as needed, taking into account the other learning axioms. An ethical stance is adopted that holds that informed individuals should be entitled to maintain the practices they prefer.

Attitude to Health↗
PubMed1996

Developing and evaluating the student assessment system in the preclinical problem-based curriculum at Sherbrooke.

BACKGROUND: Students' learning was used as an outcome measure in the first phases of the major curriculum reform started in 1987 by the Université de Sherbrooke Faculty of Medicine, which shifted from a traditional to a student-centered, problem-based learning (PBL) and community-oriented program. The system for evaluating preclinical students' learning is intended to reinforce the integration of basic and clinical sciences. METHOD: To discover whether the evaluation system was fulfilling its intended goals, the authors used data from the classes of 1991-1993 to assess the reliability and validity of three evaluation instruments. The three instruments were (1) written examinations composed of multiple-choice questions (MCQs), short-answer questions (SAQs), and problem-analysis questions (PAQs); (2) PBL tutor rating forms that evaluate students' reasoning skills, communication and group-interaction skills, and autonomy and humanism; and (3) clinical skills evaluations, including objective structured clinical examinations (OSCEs). The weights allocated to the instruments reflected how the faculty valued each evaluation dimension in each of the three phases of the preclinical curriculum. RESULTS: Reliability indexes improved throughout the system implementation. The written examinations proved to have content validity according to the PBL learning objectives. As evaluated by students, the PAQs were found to be at a taxonomic level that assessed ability to analyze information a third of the time in the first year of implementation of the PBL curriculum and 17% in the second year. Variations and correlations of students' mean performances across instructional units and between the evaluation instruments led to the development of a student longitudinal performance profile to be used before yearly promotion decisions are proposed. The profile was introduced in the fifth year of PBL implementation. CONCLUSION: The system allows students to learn higher-taxonomic-level content and fulfills the institution's social responsibility of judging program outcomes and promoting qualified students, although evaluation by PBL tutors is still psychometrically questionable and the measurement of students' reasoning and ability to analyze problems is still an unfinished evaluation task.

Clinical Competence↗
PubMed1983

Cyclic adenosine 3':5'-monophosphate phosphodiesterase and its role in learning in Drosophila.

Drosophila carrying the X-linked mutation dunce (dnc) showed poor learning in a negative reinforcement olfactory conditioning paradigm (Dudai, Y., Y.-N. Jan, D. Byers, W.G. Quinn, and S. Benzer (1976) Proc. Natl. Acad. Sci. U.S.A. 73: 1684-1688). More recently, dnc flies were shown to have reduced activity for one of two cAMP phosphodiesterases (PDEs) present in normal flies, PDE II, whereas PDE form I was unaffected (Byers, D., R. L. Davis, and J. A. Kiger, Jr. (1981) Nature 289: 79-81). A micro-assay technique is described that allows the separate measurement of PDE I and PDE II in crude extracts, based on specific inhibition of PDE I [3H]cAMP hydrolysis by cGMP. Using this technique, PDE II is shown to occur normally at high specific activity in the nervous system, consistent with the hypothesis that this enzyme plays a role in neuronal function. Reduced PDE II activity correlates with poor learning in dnc flies at three developmental stages (first and third instar larva and adult), as well as in response to genetic modification of dnc gene activity. Biochemical and genetic experiments fail to reveal any abnormal regulation of PDE II in dnc. The specific activity of PDE II is shown to correlate in a one to one fashion with the level of normal dnc gene (dnc+) activity at five different doses of dnc+. These results support the hypothesis that PDE II represents the primary product of the dnc gene, indicating a role for this enzyme in Drosophila learning.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2000

Differential outcome effect in the horse.

Three horses were trained with a discrimination task in which the color (blue or yellow) of a center panel signaled the correct (left or right) response (lever press). Reinforcing outcomes for the two correct color-position combinations (blue-left and yellow-right) were varied across phases. Discrimination performance was better when the combinations were differentially reinforced by two types of food (chopped carrot pieces and a solid food pellet) than when the combinations were randomly reinforced by these outcomes or when there was a common reinforcer for each of the correct combinations. However, the discrimination performance established by the differential outcome procedure was still 80% to 90% correct, and an analysis of two-trial sequences revealed that the stimulus color of the preceding trial interfered with discrimination performance on a given trial. Our demonstration of the differential outcome effect in the horse and its further analysis might contribute to more efficient control of equine behavior in the laboratory as well as in horse sports.

Animals↗
PubMed1989

Behavioral asymmetries in visual learning of young chickens.

Two-week-old chicks were trained in a simultaneous color discrimination learning task using food reinforcement. They had to discriminate between two discs of a different color whose right-left position was alternated at random. Results showed that chicks made more errors when the nonreinforced color was placed on the left with respect to the animal's body rather than when it was placed on the right. When chicks were trained on a right-left discrimination with two discs of identical color the asymmetry disappeared. Results are discussed in relation to current evidence for functional lateralization in the avian brain.

Animals↗