Neuromuscular junction (NMJ) electrophysiology is performed on Drosophila third instar larvae to study human diseases characterized by abnormal electrophysiology, such as epilepsy and ALS. The larva is fileted down the length of its body to expose the ventral nerve cord and body wall muscles. Electrodes are then inserted into a motor neuron and a corresponding body wall muscle. This method of studying the NMJ is accurate, but difficult and labor-intensive, so electrophysiology is combined with genetic screens to fully characterize NMJ mutations.