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Serge Faumont "Bases génétiques, moléculaires et neuronales de la genèse de stratégies comportementales adaptatives chez C. elegans".

Abstract :

C.elegans is an emerging system in the neurophysiological analysis of behavior.
It is an experimental organism whose genetics, development, and nervous system are unusually well described at the cellular and molecular levels: it has a compact nervous system of only 302 neurons, a nearly complete anatomical wiring diagram, and a wide range of genetic and physiological techniques for linking genes and molecules to behavior

Our objective is to understand the neuronal basis of chemotaxis behavior in C. elegans. Chemotaxis, the ability of an animal to orient its locomotion with respect to a chemical gradient, is a simple, yet widespread, form of spatial orientation behavior. The chemotaxis behavior of C. elegans raises, in simplified form, the key question of how the nervous system transforms sensory input into motor output to regulate a goal-directed response

In this seminar I will first present a characterization of the sensorimotor transformation underlying chemotaxis. We used this sensorimotor transformation to build a kinetic model of C. elegans chemotaxis behavior, and showed that our model can account for the behavior. We next showed that the transformation can be dissected into components to which identified neurons can be assigned, and that specific genes can alter parts of the transformation. Finally, I will present recent and mostly unpublished data showing the activity of some of the neurons involved in chemotaxis. We were able to record simultaneously behavior and neuronal activity in semi-restrained animals, using the genetically-encoded calcium sensor Cameleon, and thereby correlate parameters of the neuronal activity with behavioral parameters.

The use of C. elegans as an experimental model allows us to combine genetic and molecular biology tools with neurophsysiological analysis and behavioral analysis, paving the way for a comprehensive explanation of spatial orientation that spans the molecular, cellular, network, and behavioral levels of organization.

Selected publications

Faumont S, Lockery SR (2005). The awake behaving worm: simultaneous imaging of neuronal activity and behavior in intact animals at millimeter scale. J Neurophysiol. 95:1976-81.
Faumont S, Miller AC, Lockery SR (2005). Chemosensory behavior of semi-restrained Caenorhabditis elegans. J Neurobiol. 65:171-8.
Miller AC, Thiele TR, Faumont S, Moravec ML, Lockery SR (2005). Step-response analysis of chemotaxis in Caenorhabditis elegans. J Neurosci. 25:3369-78.
Zariwala HA, Miller AC, Faumont S, Lockery SR (2003). Step response analysis of thermotaxis in Caenorhabditis elegans. J Neurosci. 23:4369-77.

Daniel Cattaert