What is in a word? Neuron: Early usage and evolution in antiquity to its long-lasting current significance

ABSTRACT

Neuron, a Greek term with a rustic background, made much of its way to its current significance since antiquity, when full recognition was achieved that sensory and motor signals travel through the animal body along nerves (neura, plural). Drawing from classic and recent historical scholarship, this study identifies the successive steps toward such a major breakthrough, starting from the usage of the expression in archaic times and continuing up to the much later transference of a mature theory into the modern world. It is shown that four main consecutive stages may be distinguished in the process: (a) incorporation of the word into early anatomical terminology; (b) theorizing on material composition, origin, properties, and role of the neura in animal bodies; (c) functional association of the neura with a transmitting vehicle; (d) identification of true anatomical and physiological correspondences. Upon this over 2000-year-old foundation is still being built one of the most relevant and fascinating scientific adventures of all time.

KEYWORDS:

• Aristotle
• Diogenes of Apollonia
• Empedocles
• Erasistratus
• Galen
• Herophilus
• Hippocrates
• Leonardo da Vinci
• neuron
• neurophysiology
• nerve
• Plato
• Ramón y Cajal
• Vesalius

Acknowledgments

The author is indebted to Dr. Stanley Finger for his always pertinent and knowledgeable comments on a former version of this work. Helpful remarks by the anonymous kind reviewers also contributed to achieve the present article.

Notes

¹ The brief quote spreads over four pages as a result of its beginning at the bottom of page 160 on the convenient page-by-page, face-to-face format of scholarly translations published in the Loeb Classical Library.

² References to Plato’s works are here indicated by work title followed by page number and page-section letters, according to the standard notation based on the classic Stephanus edition, as well as with the usual page-number method for modern editions

³ Titles of Aristotle’s works are here abbreviated as follows: GA, Generation of Animals; HA, History of Animals; MA, Movement of Animals; OB, On Breath; PA, Parts of Animals. References to Aristotle's works are here indicated by work title initials followed by book number in Roman numerals, then chapter number in Arabic numerals, then page number and column letter (a or b), and finally line numbers, according to the standard notation based on the classic Bekker edition, as well as with the usual page-number method for modern editions.

⁴ Titles of Galen’s works are here abbreviated as follows: AP, Affected Parts; BA, Blood in Arteries; DHP, Doctrines of Hippocrates and Plato; DP, Differences in Pulse; MM, Movement of Muscles; NF, Natural Faculties; P, Plenitude; TPC, Tremors, Palpitations, Convulsions; UPB, Usefulness of Parts of the Body. References to Galen's works are here indicated by work title initials followed by book number in Roman numerals, and then chapter number in Arabic numerals, as well as with the usual page-number method for modern editions.