PSICS: a new tool for simulation of stochastic ion channels in neurons with complex dendritic and axonal morphologies

How a neuron processes its inputs is profoundly influenced by the distribution of ion channels on its axons and dendrites. Although a great deal is know about the gating of single ion channels, relatively few models of signal processing in neurons account for stochastic fluctuations in single ion channel activity. It has been particularly difficult to investigate the consequences of stochastic ion channel gating in the fine dendritic and axonal processes of neurons with complex morphologies, yet these areas of the cell are where stochastic fluctuations may have greatest functional impact. Here we introduce Parallel Stochastic Ion Channel Simulator (PSICS), a new computational tool that enables efficient and straightforward generation, simulation and visualization of models containing stochastic ion channels distributed across dendritic or axonal structures. PSICS allows arbitrary distribution of individual ion channels while also substantially reducing the time required for accurate stochastic simulations of electrical activity in neurons with complex morphologies. We demonstrate the use of PSICS by evaluating the consequences of stochastic ion channel gating in neurons with distinct dendritic architectures.