These programs (VCLAMP and CCLAMP), written by J.R. Huguenard and D.A. McCormick, are designed to simulate thalamic relay neuron behavior in both Voltage Clamp and Current Clamp modes, and are based on biophysical data obtained from voltage clamp experiments. The software is written in Turbo C and will work on any PC based system. Performance will be enhanced if a mathe- matical coprocessor is detected. Currently EGA, VGA, and Hercules modes are supported, but the programs should work with any graphics display as long as an appropriate BGI driver is available. The installation program should be invoked by typing INSTALL followed by the name of the drive and directory where the models are to reside. For example, INSTALL C: \MODELS will install the models in the MODELS subdirectory of the C drive. Please specify both drive and directory for the rudimentary installa- tion program. The programs are included in a self-extracting archive file named GROW_PRG.EXE. Please direct any comments or questions to JH at John.Huguenard@stanford.edu.