Review Cajal: Lessons on brain development Fernando de Castro a,b, ⁎ , Laura López-Mascaraque c , Juan A. De Carlos c a Grupo de Neurobiología del Desarrollo (Unidad de Neurología Experimental), Hospital Nacional de Parapléjicos, Finca “La Peraleda” s/n, E-45071-Toledo, Spain b Instituto de Neurociencias de Castilla y León-INCyL, Universidad de Salamanca, Avenida de Alfonso X “el Sabio” s/n, E-37007-Salamanca, Spain c Instituto Cajal (CSIC), Avenida del Dr. Arce no. 37, E-28002-Madrid, Spain ARTICLE INFO ABSTRACT Article history: Accepted 31 January 2007 Available online 6 February 2007 In 1906, Santiago Ramón y Cajal was awarded the Nobel Prize in Physiology or Medicine in recognition of his work on the structure of the nervous system. At that time, almost all of Cajal's work was carried out using the Golgi method, a technique devised by the Italian scientist Camillo Golgi, with whom he shared this prize. Cajal introduced several modifications to the method developed by Golgi and, to avoid the problems encountered in staining myelinated neurons, part of his studies were carried out on embryos and very young animals (the “ontogenetic method”). In this way, Cajal begin to describe aspects of the development of the nervous system. Here, we review some of his wonderful discoveries (for example, the description of the axonal growth cone) from which he derived some of his main theories on the anatomy and physiology of the nervous system: the chemotactic hypothesis and the neuron doctrine. © 2007 Elsevier B.V. All rights reserved. Keywords: Golgi Cajal Contents 1. Introduction ......................................................... 482 2. The Golgi method ...................................................... 482 3. The histogenesis of the cerebellum confirms the individuality of neurons ....................... 483 4. The growth cone ....................................................... 484 5. The chemotactic or neurotropic hypothesis ........................................ 485 6. Neurotropic action of the epithelia ............................................. 486 7. Cell migration ........................................................ 487 8. Conclusions.......................................................... 487 Acknowledgments ......................................................... 487 References ............................................................. 488 BRAIN RESEARCH REVIEWS 55 (2007) 481 – 489 ⁎ Corresponding author. Grupo de Neurobiología del Desarrollo (Unidad de Neurología Experimental), Hospital Nacional de Parapléjicos, Finca “La Peraleda” s/n, E-45071-Toledo, Spain. Fax: +34 925 247745. E-mail addresses: fdec@sescam.jccm.es, fdecastro@usal.es (F. de Castro). 0165-0173/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.brainresrev.2007.01.011 available at www.sciencedirect.com www.elsevier.com/locate/brainresrev