Fig. 1

Simulation domain and model components. The domain for all simulations of this study was a cylindrical dendrite 50 μm in length with variable radius containing a centrally positioned cylindrical ER of variable radius. The rotational symmetry of the domain was used to reduce the problem to two dimensions (axial and radial position). The calcium model contains calcium in the cytosol and the ER as well as calbindin (CalB) in the cytosol. The dynamics of both are governed by a diffusive process and a buffering reaction. Calcium can cross the ER membrane through RyR channels and SERCA pumps, the plasma membrane through PMCA and NCX pumps. Each simulation was initiated by a 1 ms calcium influx through the left end of the cytosol