The reason for this was three-fold; first, animals at 1 week of age are best and more reliable to observe and quantify the changes in fluorescently tagged α-synuclein and body bends; secondly, L4 + 7 days showed the best balance of the number of live and dead worms; and thirdly, worms at this stage of development are predicted to be the age of worm that best represents humans with PD [37,68,69]. Here, SNCA is linked to Parkinson disease.