or (in case of GCaMP imaging) immobilized with 0.5 mg/ml of the non-depolarizing
neuromuscular junction blocker mivacurium chloride (Abcam). For confocal
microscopy, animals were mounted laterally in 1% ultrapure low melting point
agarose (Invitrogen) on a glass coverslip. The coverslip was flipped over on a
glass slide with a ring of high-vacuum grease filled with a drop of
Danieau’s solution to prevent drying out of the agarose. For lightsheet
microscopy, embryos were mounted upright in low melting point agarose in a
U-shaped glass capillary (Leica). After imaging, the animals were either
sacrificed or released from the agarose using microsurgery blades and kept
individually until further use.