Fine-grained model of the sensorimotor control underlying Drosophila larval chemotaxis
Chemotaxis is a powerful paradigm to study how sensory stimulations drive orientation behaviors in an organism. Drosophila larvae navigate odor gradients by controlling the duration of runs and the direction of turns. A turn is preceded by lateral head sweeps (“casts”) that sample the stimulus from...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/665160 |
| Acceso en línea: | http://hdl.handle.net/10803/665160 |
| Access Level: | acceso abierto |
| Palabra clave: | Sensorimotor control Chemotaxis Olfactory sensory neurons Agent-based modeling High-resolution tracking Electrophysiology Control sensorio-motor Quimiotaxis Neuronas sonsoriales del olfato Rastreador de larvas Electrofisiología 612 |
| Sumario: | Chemotaxis is a powerful paradigm to study how sensory stimulations drive orientation behaviors in an organism. Drosophila larvae navigate odor gradients by controlling the duration of runs and the direction of turns. A turn is preceded by lateral head sweeps (“casts”) that sample the stimulus from the surroundings. In addition, larvae correct their course towards the odor source during runs, a phenomenon called “weathervaning”. Peristaltic waves that propagate along the body axis drive forward run events. We showed that the peristaltic wave cycle acts as a natural unit of movement and sets a physical constraint on the amount of reorientation achieved during runs. Moreover, head-casts are strictly observed within the bounds of the peristaltic cycle that can be categorized into either runcasts or stop-casts based on the presence or absence of the peristaltic wave respectively. Integrating behavioral experiments and extracellular electrophysiological recordings from the olfactory sensory neurons (OSNs), we observed a remarkable ability of larva to sense, to process and to act at short timescales of head-casts. In particular, we found that the larval sensorimotor system is able to modulate the amplitude of stop-casts based on the changes in the OSN firing rate during casts. Finally, integrating models for OSN activity, peristaltic locomotion, and behavioral quantification, we built an agent-based model that recapitulates essential aspects of larval chemotactic behavior. Overall, our findings provide a new formalism to study larval sensorimotor control. Additionally, we developed a high spatiotemporal resolution larval tracker with an ability to detect and precisely stimulate individual sensory organs. The tracker is highly effective tool to discern neural basis of behaviors occurring at short timescales in Drosophila larvae and other model systems. |
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