KeywordsNeuronal Circuit, Synaptogenesis, Optic Tectum, Axonal Transport, Zebrafish
Neuronal circuits represent the cellular substrate of complex behaviors. Understanding their development and function constitutes therefore a central question in neuroscience. We use the zebrafish visual system as a model to understand neuronal circuit formation taking advantage of its small size and transparency. Our studies will provide crucial information to unravel the function of more complex brains such as ours, and perhaps to better understand the origin of many neurological disorders.
|A major goal of modern neuroscience is the complete understanding of neuronal circuits development and function in an intact behaving animal. Our group examines the formation and function of the visual system of zebrafish larvae using in vivo time-lapse microscopy and state-of-the-art “connectomic” and “optogenetic” approaches to monitor and perturb neuronal activity. We apply complementary cellular and molecular analysis to dissect this circuit and identify the neuronal substrate of visual behaviors.|
Neuronal circuit development in the zebrafish optic tectum
We focus our analysis on the zebrafish optic tectum. This midbrain structure has emerged as a potentially tractable visuomotor transformer, which integrates visual and other sensory inputs to produce a motor response. We apply anatomical and functional studies to a better understand of how behavior can be controlled by neuronal circuits. The tectum sits at the surface of the larval brain, located just under a single-layed epithelial tissue, and is divided into two main areas, the stratum periventriculare (SPV), which contains the cell bodies of most tectal neurons (PVNs), and the synaptic neuropil area, which contains their dendrites and axons, as well as the axons of retinal afferents.
Analysis of SIN connectivity and function
We are particularly interested in understanding the function, development and connectivity of a newly characterized class of inhibitory interneurons located in the superficial part of the tectal neuropil named SINs (superficial inhibitory interneurons). Our previous work based on functional imaging has placed SINs at the center of a tectal micro-circuit for size tuning of visual stimuli. We will dissect this working model by analyzing the physiological properties of SINs and their development and connectivity at the level of single synapses by imaging these cells in vivo using fluorescent reporters in transgenic animals.
Axonal transport function in retinotecal axonal development and synaptogenesis.
We are interested in investigating the effects of mutations in molecular motors on axonal branching and synaptogenesis. We focus our analysis to the retinotectal system to unravel the molecular processes that control its development. Using single cell loss-of-function experiments we want to perturb the expression or the activity of molecular motors and associated proteins. Given the links that have already been made between many of these proteins and human neurodegenerative and psychiatric disorders, our studies will provide novel insights into the underlying molecular mechanisms.