AUTOMATIC REGISTRATION OF HISTOLOGICAL SECTIONS Ignacio Arganda-Carreras Biocomputing Unit, National Centre of Biotechnology (CSIC). Madrid, SPAIN Escuela Politicnica Superior. Universidad Autonoma de Madrid. Madrid, SPAIN Three-dimensional reconstructions of biological structures from histological sections involve diverse difficulties. The first problem in such a process is the need of recovering the original tissue alignment, which was lost in the sectioning process and distorted due to the tissue staining and mounting process. Different complex methods have been proposed to solve the registration problem in 2D, based on fiduciary markers, elastic deformations of the images, piece-wise registration, warping, etc. However, their complexity makes these methods not practical for large images. We will expose in this informal seminar all the methods applied with this aim by the student in his search for the most efficient and reliable registration algorithm. Ignacio Arganda-Carreras is a PhD student in the PhD program in "Computer Science and Telecommunications" of the Polytechnic School in the Universidad Autonoma of Madrid. He is a member of the Biocomputing Unit in the National Centre of Biotechnology, an interdisciplinary team of people working on Computational and Structural Biology and Bioinformatics. He developed all his image registration research in the group lead by Carlos Ortiz-de-Solsrzano, focused on the study of the breast cancer progression (http://carlos.lbl.gov).