TY - JOUR T1 - Barriers to Diffusion in Dendrites and Estimation of Calcium Spread Following Synaptic Inputs A1 - Biess, Armin A1 - Korkotian, Eduard A1 - Holcman, David Y1 - 2011/10/13 N2 - Author Summary Diffusion is one of the main transport phenomena involved in signaling mechanisms of ions and molecules in living cells, such as neurons. As the cell cytoplasmic medium is highly heterogeneous and filled with many organelles, the motion of a diffusing particle is affected by many interactions with its environment. Interestingly, the functional consequences of these interactions cannot be directly quantified. Thus, in parallel with experimental methods, we have developed a computational approach to decipher the role of crowding from binding. We first study here the diffusion of a fluorescent marker in dendrites by a one-dimensional effective diffusion equation and obtained an effective diffusion constant that accounts for the presence heterogeneity in the medium. Furthermore, comparing our experimental data with simulations of diffusion in a crowded environment, we estimate the intracellular calcium spread in dendrites after injection of calcium transients. We confirm that calcium spread is mainly regulated by fixed buffer molecules, that bind temporarily to calcium, and less by the heterogeneous structure of the surrounding medium. Finally, we find that after synaptic inputs, calcium remains restricted to a domain of 2.5 µm to each side of the input location independent of the input frequency. JF - PLOS Computational Biology JA - PLOS Computational Biology VL - 7 IS - 10 UR - https://doi.org/10.1371/journal.pcbi.1002182 SP - e1002182 EP - PB - Public Library of Science M3 - doi:10.1371/journal.pcbi.1002182 ER -