Dendritic Spines and Development: Towards a Unifying Model of Spinogenesis—A Present Day Review of Cajal's Histological Slides and Drawings
Figure 5
Development of dendritic spines, visual cortex, 19-day-old mouse according to Freire [16, Figures 1, 2, and 3], using serial section electron microscopy. (1a) and (1b) show two medial sections through a dendritic spine in phase 1 of development, the synaptic zone is not developed, but it is contacted by one axon (arrows), no cistern (sacs) of the spine apparatus is present, 19-day-old mouse reared in the dark. (2a) and (2b) show two medial sections through a phase 2 spine, a synaptic zone has appeared (arrows) but is not sacs of the spine apparatus, 19-day-old normal mouse. (3a) and (3b) show two medial sections through a phase 3 dendritic spine with cisterns in its spine apparatus (SA), and a well-developed synaptic zone (arrows).
