%A Morales,Juan %A Alonso-Nanclares,Lidia %A Rodriguez,José-Rodrigo %A Defelipe,Javier %A Rodriguez,Ángel %A Merchan-Perez,Angel %D 2011 %J Frontiers in Neuroanatomy %C %F %G English %K 3D Reconstruction,focused ion beam,quantification,Scanning electron microscopy,segmentation,Software,Synapses %Q %R 10.3389/fnana.2011.00018 %W %L %M %P %7 %8 2011-March-18 %9 Methods %+ Dr Angel Merchan-Perez,Universidad Politécnica de Madrid,Laboratorio de Circuitos Corticales (CTB),Edificio Anexo a Genómica de Plantas,Campus Montegancedo S/N,Pozuelo de Alarcón,28223,Madrid,Spain,angel.merchan@upm.es %+ Dr Angel Merchan-Perez,Universidad Politécnica de Madrid,Dept. Arquitectura y Tecnología de Sistemas Informáticos,Campus Montegancedo S/N,Pozuelo de Alarcón,Pozuelo de Alarcón,28223,Madrid,Spain,angel.merchan@upm.es %+ Dr Angel Merchan-Perez,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas,CIBERNED,Madrid,Spain,angel.merchan@upm.es %# %! ESPINA: automated segmentation of synapses %* %< %T Espina: A Tool for the Automated Segmentation and Counting of Synapses in Large Stacks of Electron Microscopy Images %U https://www.frontiersin.org/articles/10.3389/fnana.2011.00018 %V 5 %0 JOURNAL ARTICLE %@ 1662-5129 %X The synapses in the cerebral cortex can be classified into two main types, Gray's type I and type II, which correspond to asymmetric (mostly glutamatergic excitatory) and symmetric (inhibitory GABAergic) synapses, respectively. Hence, the quantification and identification of their different types and the proportions in which they are found, is extraordinarily important in terms of brain function. The ideal approach to calculate the number of synapses per unit volume is to analyze 3D samples reconstructed from serial sections. However, obtaining serial sections by transmission electron microscopy is an extremely time consuming and technically demanding task. Using focused ion beam/scanning electron microscope microscopy, we recently showed that virtually all synapses can be accurately identified as asymmetric or symmetric synapses when they are visualized, reconstructed, and quantified from large 3D tissue samples obtained in an automated manner. Nevertheless, the analysis, segmentation, and quantification of synapses is still a labor intensive procedure. Thus, novel solutions are currently necessary to deal with the large volume of data that is being generated by automated 3D electron microscopy. Accordingly, we have developed ESPINA, a software tool that performs the automated segmentation and counting of synapses in a reconstructed 3D volume of the cerebral cortex, and that greatly facilitates and accelerates these processes.