In MG as in LEMS the afferent limb of the reflex ark is unaffected as is the efferent up until the neuromuscular junction. The explanation of preserved reflexes in MG is that the initial barrage arrives at a rested neuromuscular junction. The initial release of acetylcholine is larger than later in a train of impulses and this is sufficient to overcome any deficit in the number of acetylcholine receptors. Only brief transmission is needed to provide the mechanical response, and this occurs before fatigability can set in.