Development is driven by robust processes across scales and functions. Physics of liquid crystals reveals as fruithfull in describing the evolution of spindle-shaped cells such as myoblasts. We focus on muscle precursors to create multicellular capillary bridges and to apply forces on these nematic-like micro-tissues in 3D. This mechancal constraints allows to obtain multilayererd actin structure mostly aligned. The internship aims to explore how competiting electrical cues mimicking motoneurons stimulation can interfere in this architecture. The project involves monitoring actin filament dynamics using 2-photon microscopy, and identify applying optogenetic stimulation.