| 1. |
- Root, Cory M., et al.
(författare)
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A presynaptic gain control mechanism fine-tunes olfactory behavior
- 2008
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Ingår i: Neuron. - 0896-6273. ; 59:2, s. 311-21
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Tidskriftsartikel (refereegranskat)abstract
- Early sensory processing can play a critical role in sensing environmental cues. We have investigated the physiological and behavioral function of gain control at the first synapse of olfactory processing in Drosophila. Olfactory receptor neurons (ORNs) express the GABA(B) receptor (GABA(B)R), and its expression expands the dynamic range of ORN synaptic transmission that is preserved in projection neuron responses. Strikingly, each ORN channel has a unique baseline level of GABA(B)R expression. ORNs that sense the aversive odorant CO(2) do not express GABA(B)Rs and do not have significant presynaptic inhibition. In contrast, pheromone-sensing ORNs express a high level of GABA(B)Rs and exhibit strong presynaptic inhibition. Furthermore, pheromone-dependent mate localization is impaired in flies that lack GABA(B)Rs in specific ORNs. These findings indicate that different olfactory receptor channels employ heterogeneous presynaptic gain control as a mechanism to allow an animal's innate behavioral responses to match its ecological needs.
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| 3. |
- Söderlind, Gustaf, et al.
(författare)
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Evaluating Numerical ODE/DAE Methods, Algorithms and Software
- 2006
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Ingår i: Journal of Computational and Applied Mathematics. - : Elsevier BV. - 0377-0427. ; 185:2, s. 244-260
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Tidskriftsartikel (refereegranskat)abstract
- Until recently, the testing of ODE/DAE software has been limited to simple comparisons and benchmarking. The process of developing software from a mathematically specified method is complex: it entails constructing control structures and objectives, selecting iterative methods and termination criteria, choosing norms and many more decisions. Most software constructors have taken a heuristic approach to these design choices, and as a consequence two different implementations of the same method may show significant differences in performance. Yet it is common to try to deduce from software comparisons that one method is better than another. Such conclusions are not warranted, however, unless the testing is carried out under true ceteris paribus conditions. Moreover, testing is an empirical science and as such requires a formal test protocol; without it conclusions are questionable, invalid or even false. We argue that ODE/DAE software can be constructed and analyzed by proven, ''standard'' scientific techniques instead of heuristics. The goals are computational stability, reproducibility, and improved software quality. We also focus on different error criteria and norms, and discuss modifications to Daspk and Radau5. Finally, some basic principles of a test protocol are outlined and applied to testing these codes on a variety of problems.
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