A genus of squid often used in neurology studies, and important in early studies uncovering the electrical properties of neurons and axons. It has a very large axon (a "Giant Axon"), which was used to great advantage in the work of J. Z. Young.

Young, a British neurologist and zoologist, found in the mid-1930s that the mantle of the squid is innervated by a giant axon up to 1 millimeter in diameter.

This huge axon made it possible to perform experimental work that proved incredibly illuminating with regard to the membrane and trans-membrane properties of neurons and their axons. This, in turn, has led to much better understanding of neuron and synapse function.

A species indigenous to the North Atlantic Ocean, Loligo Pealeii (also spelled Loligo Pealei) is said to have been used in the work of Kenneth Cole, Alan Hodgkin, and Andrew Huxley in their neurobiology experiments. Hodgkin, Huxley, and John Eccles received the Nobel Science Prize in Physiology or Medicine in 1963 for their studies of this amazing organism.

Another Loligo species often used in neurological studies is Loligo Forbesii (also spelled Loligo Forbesi - Streenstrup 1857).

Note: there is considerable confusion and disorder in this classification group (Loliginidae).