http://precedings.nature.com/users/da2f172d3bdf79ce7a2c44b1d215806c/ Documents posted by Björn Brembs Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://dx.doi.org/10.1038/npre.2009.2926.1 Learning about the consequences of our actions (operant learning) is one of the major ways in which we learn to understand the world we live in. Despite our recent advances in the neurobiology of learning and memory, this “learning-by-doing” has largely withstood neurobiological scrutiny. This proposal aims to elucidate the molecular and neurobiological mechanisms of spontaneous behavioral choice and how decision-making is modulated by the consequences of such actions. This research will be done in a genetically amenable model system, the fruit fly Drosophila. We will use state-of-the-art genetic and behavioral techniques to identify the circuitry and molecular processes involved in generating spontaneous turning behavior and its modulation by operant learning. Operant learning is only one system among many which govern the organization of behavior. The long-term prospect of this research beyond this application is to understand how multiple memory systems interact to accomplish adaptive behavioral choice and decision-making. http://dx.doi.org/10.1038/npre.2009.2926.1 Fri, 06 Mar 2009 17:24:26 UTC The neurobiology of spontaneous actions and operant learning in Drosophila doi:10.1038/npre.2009.2926.1 2009-03-06 Björn Brembs Nature Precedings 2009-03-06T17:24:26Z Presentation Neuroscience http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2009.2801.1 A short intro into the impact factor and its limitations and potential successors. http://dx.doi.org/10.1038/npre.2009.2801.1 Wed, 21 Jan 2009 14:46:03 UTC Reputation, authority and incentives. Or: How to get rid of the Impact Factor doi:10.1038/npre.2009.2801.1 2009-01-21 Björn Brembs Nature Precedings 2009-01-21T14:46:03Z Presentation Chemistry Molecular Cell Biology Bioinformatics http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.2171.1 Our past experience is one of the primary sources of information when faced with a choice. We ask ourselves: “what will happen if I do this?” Accurately predicting the consequences of our actions is usually modeled by operant (instrumental) learning experiments. These types of experiments are often contrasted with classical (Pavlovian) conditioning experiments in a dichotomy. And indeed, different brain circuits mediate the acquisition of skills and habits (via operant/instrumental learning) and the acquisition of facts (via classical/Pavlovian learning). However, realistic learning situations always comprise interactions of skill- and fact-learning components (composite learning). Fixed flying Drosophila melanogaster at the torque meter provide one of the very few systems where the relationship of operant and classical predictors in composite learning can be studied with sufficient rigor. The latest experiments show that the textbook operant/classical dichotomy is misleading and that instead composite learning consists of multiple interacting memory systems. These interactions between predictive stimuli (classical component) and goal-directed actions (operant component) make composite conditioning more effective than the operant and classical components alone (learning-by-doing, generation effect). Rutabaga (rut) mutants are impaired in learning about the (classical) stimuli, but show improved (operant) behavior learning. This is the first evidence that operant and classical conditioning differ not only at the circuit, but also at the molecular level. The interaction between operant and classical components is reciprocal and hierarchical, such that the classical suppresses the operant component. Experiments with transgenic flies demonstrate that this suppression of operant learning is mediated by the mushroom-bodies and serves to ensure that the classical memories can be generalized for access by other behaviors. Extended training can overcome this suppression and transforms goal-directed actions into habitual responses. This interaction leads to efficient learning, enables generalization and prevents premature habit-formation. http://dx.doi.org/10.1038/npre.2008.2171.1 Wed, 17 Sep 2008 12:49:48 UTC Mushroom-bodies regulate habit formation in Drosophila doi:10.1038/npre.2008.2171.1 2008-09-17 Björn Brembs Nature Precedings 2008-09-17T12:49:48Z Presentation Genetics & Genomics Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1354/version/1 At the heart of learning-by-doing lies a well-known psychological phenomenon: information will be remembered better if it is actively generated rather than passively read or heard. First described in humans, this generation effect can also be observed in various animal models. However, the neurobiological mechanisms underlying the generation effect are unknown. Here we show that two reciprocal interactions between its active and passive components contribute to the generation effect in flies. One interaction consists of the active (skill-learning) component facilitating the passive (fact-learning) component. Fact-learning, on the other hand, inhibits skill-learning. Experiments with adenylyl cyclase I deficient rutabaga mutant flies revealed that the fact- but not the skill-learning component requires this evolutionarily conserved learning gene. Using mushroom-body deficient transgenic flies we observed that the mushroom-bodies mediate the inhibition of skill-learning. This inhibition also enables generalization and prevents premature habit formation. Extended training in wildtype flies produced a phenocopy of mushroom-body impaired flies, such that generalization was abolished and goal-directed actions were transformed into habitual responses. Thus, our results identify various neural processes underlying learning-by-doing, delineate some of their synergisms and provide a framework for further dissecting them in a genetically tractable model system. http://precedings.nature.com/documents/1354/version/1 Tue, 20 Nov 2007 18:16:18 UTC Dissecting the mechanisms of learning-by-doing in Drosophila hdl:10101/npre.2007.1354.1 2007-11-20 Björn Brembs Nature Precedings 2007-11-20T18:16:18Z Manuscript Genetics & Genomics Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/905/version/1 Different brain circuits mediate the acquisition of skills and habits (via operant/instrumental learning) and the acquisition of facts (via classical/Pavlovian learning). Realistic learning situations always comprise interactions of skill- and fact-learning components (composite learning). So far, these interactions have escaped thorough scrutiny. Fixed flying Drosophila melanogaster at the torque meter provide one of the very few systems where the relationship of operant and classical predictors in composite learning can be studied with sufficient rigor. Experiments with wildtype, mutant and transgenic flies show that there is an interaction between predictive stimuli (classical component) and goal-directed actions (operant component) which makes composite conditioning more effective than the operant and classical components alone. Rutabaga (rut) mutants are impaired in learning about the (classical) stimuli, but show improved (operant) behavior learning. This is the first evidence that operant and classical conditioning differ not only at the circuit, but also at the molecular level. The interaction between operant and classical components is reciprocal and hierarchical, such that an impaired classical component (in rut flies) suppresses retrieval and an intact classical component suppresses acquisition of the operant component. Experiments with transgenic flies demonstrate that this suppression of operant acquisition is mediated by the mushroom-bodies and serves to ensure that the classical memories can be generalized for access by other behaviors. Extended training can overcome this suppression and transforms goal-directed actions into habitual responses. In conclusion, composite conditioning consists of two components with reciprocal, hierarchical interactions. Acquisition of the rut-dependent classical component suppresses acquisition of the rut-independent operant component via the mushroom-bodies. The operant component facilitates acquisition of the classical component via unknown, non-mushroom-body pathways. This interaction leads to efficient learning, enables generalization and prevents premature habit-formation. Habit formation after extended training reveals the gate-keeping role of the mushroom-bodies, allowing only well-rehearsed behaviors to consolidate into habits. http://precedings.nature.com/documents/905/version/1 Tue, 04 Sep 2007 12:04:55 UTC Mushroom-bodies mediate hierarchical interactions between fact- and skill-learning in Drosophila hdl:10101/npre.2007.905.1 2007-09-04 Björn Brembs Nature Precedings 2007-09-04T12:04:55Z Manuscript Genetics & Genomics Neuroscience http://creativecommons.org/licenses/by/2.5/