Researchers have achieved patch-clamp studies of an elusive part of mammalian myelinated nerves called the Nodes of Ranvier. At the nodes, they found unexpected potassium channels that give the myelinated nerve the ability to propagate nerve impulses at very high frequencies and with high conduction speeds along the nerve. Both qualities are necessary for fast conduction of sensations and rapid muscle control in mammals — keys to an animal’s survival in a predator-prey world.