S11-02 Activity and signalling in the development of neural morphology and locomotion

Abstract

Whole animal behaviors require precise wiring of the nervous system. Yet how neuronal wiring translates into defined behaviors is not well understood. To study the interplay between nervous system development and behavior, we focus on neuronal wiring (axonal guidance and synapse formation) controlling defined motor behaviors. In genetic screens for motor axon guidance and synapse formation, we have identified a series of genes that have allowed us to dissect at the molecular and cellular level how motor axons navigate from the spinal cord to their muscle targets, and how they form the first neuromuscular synapses [1– 3]. In parallel, we have conducted genetic screens to identify genes controlling the modulation of motor behaviors. We have focused on the startle response, which is a evolutionary conserved and well-characterized motor behavior modulated by sensory stimuli. For example, the display of a sub-threshold stimulus (i.e. a stimulus too weak to elicit a response on its own) just prior to a startling stimulus, suppresses the startle response through neural processing called sensorimotor gating. Despite its importance (patients with schizophrenia have severe sensorimotor deficits) the molecular and cellular pathways underlying sensorimotor are not very well understood. We have recently established the zebrafish as a model to study sensorimotor gating, and in a genetic screen we have identified several mutants with specific defects in this process [4]. We will discuss our ongoing efforts to integrate neuronal wiring (axonal guidance and synapse formation) during development with the function of neural circuits controlling defined motor behaviors (sensorimotor gating, phototaxis).