research_aim1

Basic mechanisms of visual maps formation

The Problem: 

Visual connectivity within the superior colliculus requires a complex and precise organization of neuronal connections, also called topographic visual maps. The mechanisms controlling the development of visual maps are still under intense investigation in our lab and others. Several families of chemical guidance cues are involved and more recently it has been shown that a physical parameter is also important – the density of the brain tissue, sensed by a novel type of molecules, mechanosensors. The general hypothesis is that all these components interact to organize the visual network however nothing is known about these interactions.

The Questions:

What are the mechanisms of interaction? What is the relative importance of chemical cues versus mechanosensors? Can we model these interactions so that we can predict network formation as it has been previously done with chemical guidance cues only?

The Approach:

Using neuronal tracing coupled to state-of-the-art brain imaging (high-resolution, 2-photons and light sheet microscopy), mouse genetics (conditional knock-out and knock-in animals) and computational neurosciences (modelling in MatLab), we will study the mechanisms of visual network development in multiple animal models devoid of either chemical guidance cues, mechano-sensors or both. We will then model these mechanisms using existing or newly designed algorithms to predict visual maps development.

Discoveries and Innovation:

Savier E. and Reber M. (2018) Visual maps development: reconsidering the role of retinal Efnas and basic principle of map alignment. Front. Cel. Neurosci. 12, 77-80.

Savier E, Eglen S, Perraut M, Barthelemy A, Pfrieger FW, Lemke G and Reber M. (2017) A Molecular Mechanism for the Topographic Alignment of Convergent Neural Maps. eLife 6:e20470.

Hjorth JJ, Savier E, Sterratt DC, Reber M* and Eglen SJ*. (2015) Estimating the location and size of retinal injections from orthogonal images of an intact retina. BMC Neurosci. 16, 80.

Bevins N, Lemke G and Reber M. (2011) Genetic dissection of ratiometric EphA receptor signaling in the formation of topographic neural maps. J. Neurosci. 31, 10302-10310.

Claudepierre T, Koncina E, Pfrieger FW, Bagnard D, Aunis A and Reber M. (2008) Implication of Neuropilin 2 / Semaphorin 3F in Retinocollicular Map Formation. Dev. Dyn. 273, 3394-34403.

Lemke G and Reber M. (2005) Retinocollicular mapping: new insights from molecular genetics. Ann. Rev. Cell Dev. Biol. 21, 551-580.

Reber M, Burrola P and Lemke G. (2004) A relative signaling model for the formation of a topographic map. Nature 431, 847-853.