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meeting posters and abstracts [ posters presented at meetings and their abstracts ]
| Operant and classical components interact hierarchically in Drosophila predictive learning | |||
| Author | Björn Brembs | ||
| Author email | bjoern©brembs.net | ||
| Author website | http://brembs.net | ||
| Description | Program#/Poster#: 813.26/U5, SfN 2006. The relationship of operant and classical components in associative learning is subject to a long-standing debate. The duration of the debate can in part be explained by the fact that most learning situations comprise operant and classical components to some extent (composite conditioning): one or more initially neutral stimuli (conditioned stimulus, CS), the animal’s behavior (BH) and the reinforcer (unconditioned stimulus, US) being contingent on both. Fixed flying Drosophila melanogaster at the torque meter provide one of the very few systems where this issue can be studied with the necessary rigor. At the torque meter, flies modulate their yaw torque over a wide range attempting to turn right and left. A behavior (BH, one of two domains of yaw torque) and a stimulus (CS, one of two colors) are arranged to coincide with punishment (US, heat) in a differential operant conditioning paradigm. During training, one half of the fly’s yaw torque range is coupled with, say, green panorama illumination, while the other half is coupled with blue illumination. These yaw torque domains approximately correspond to left and right turns in free flight. A punishing heat-beam is associated with one of the colors/yaw torque domains, such that the animal learns, for instance, that turning left (BH) causes both blue illumination (CS) and heat (US), while turning right switches both the color to green and the heat off. Importantly, wildtype flies can also learn the classical color-heat (CS-US) component alone as well as the operant yaw torque-heat (BH-US) component alone. This composite BH+CS+US training is more effective than pure operant BH-US training in which only the yaw torque domain is coupled to heat without a color cue. Experiments with wildtype and rutabaga mutant flies suggest that there is a hierarchical interaction between stimuli and behavior which makes composite conditioning more effective than the operant and classical components alone. Moreover, the experiments show that the Rutabaga protein, a type 1 adenylyl cyclase that is necessary for most learning tasks flies have been subjected to, is not required for pure operant conditioning. This result shows that operant and classical conditioning can be separated not only at the behavioral and neural, but also at the molecular level. Our experiments suggest that classical or composite conditioning paradigms may not be sufficient for investigating the general neurobiological principles underlying learning and memory. | ||
| Image | no image available | ||
| Filesize | 1.81 MB | ||
| Downloads | 4510 | ||
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