Researchers find structures that enable rapid transmission of nerve impulses in insects
An animal's brain consists of two different types of cell: neurons, which process and transmit information, and glial cells, which support the neurons in a variety of ways. In 1871, the French anatomist Louis-Antoine Ranvier demonstrated something special about neurons in vertebrates: on the extensions of these nerve cells there are ring-shaped regions which lack a surrounding sheath—the myelin formed by glial cells. Together with the electrically insulating myelin sheath, the so-called nodes of Ranvier form a basis for electrical nerve impulses to be transferred very rapidly over longer distances. They "jump" from node to node at a speed of up to 100 meters per second. This "saltatory conduction" has long been seen as being specific to vertebrates.