Hindawi Publishing Corporation Neural Plasticity Volume 2010, Article ID 769207, 29 pages doi:10.1155/2010/769207 Review Article Dendritic Spines and Development: Towards a Unifying Model of Spinogenesis—A Present Day Review of Cajal’s Histological Slides and Drawings Pablo Garcıa-L´ opez,´ Virginia Garcıa-Mar´ ın,´ and Miguel Freire Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain Correspondence should be addressed to Miguel Freire,
[email protected] Received 23 September 2010; Accepted 14 November 2010 Academic Editor: Michael Stewart Copyright © 2010 Pablo Garcıa-L´ opez´ et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Dendritic spines receive the majority of excitatory connections in the central nervous system, and, thus, they are key structures in the regulation of neural activity. Hence, the cellular and molecular mechanisms underlying their generation and plasticity, both during development and in adulthood, are a matter of fundamental and practical interest. Indeed, a better understanding of these mechanisms should provide clues to the development of novel clinical therapies. Here, we present original results obtained from high-quality images of Cajal’s histological preparations, stored at the Cajal Museum (Instituto Cajal, CSIC), obtained using extended focus imaging, three-dimensional reconstruction, and rendering. Based on the data available in the literature regarding the formation of dendritic spines during development and our results, we propose a unifying model for dendritic spine development. 1. Introduction established at dendritic spines [9, 10], even though excitatory connections can also end on dendritic shafts [11, 12].