Channels -------- Simulations that illustrates the application of simple kinetic models for the most current types of receptors: AMPA and NMDA glutamatergic, GABA-A and GABA-B gabaergic. These simulations are related to the following book chapter- generates figures similar to fig 1.4 p19: Alain Destexhe, Zachary F. Mainen and Terrence J. Sejnowski Kinetic models of synaptic transmission In: Methods in Neuronal Modeling , 2nd Edition, Edited by Koch, C. and Segev, I., MIT Press, Cambridge, MA, 1998, pp. 1-25. These papers are related: Destexhe, A., Mainen, Z.F. and Sejnowski, T.J. An efficient method for computing synaptic conductances based on a kinetic model of receptor binding Neural Computation 6: 10-14, 1994. Destexhe, A., Mainen, Z.F. and Sejnowski, T.J. Synthesis of models for excitable membranes, synaptic transmission and neuromodulation using a common kinetic formalism, Journal of Computational Neuroscience 1: 195-230, 1994. (see postscript files synapse.ps.Z and markovSynapse.ps.Z) Destexhe, A., Mainen, Z.F. and Sejnowski, T.J. Fast kinetic models for simulating AMPA, NMDA, GABA(A) and GABA(B) receptors. In: Computation and Neural Systems, Vol. 4, Kluwer Academic Press, in press, 1995. (see postscript file cns94.ps.Z) The present directory contains all the files needed to run the simulations using the Interviews version of NEURON. These files are commented and should run straighforwardly, provided the NEURON simulator is installed properly. The kinetic synapse mechanism ----------------------------- This mechanisms has the following properties: 1. It is based on a simple kinetic scheme of binding of transmitter on postsynaptic receptors. This description has the advantage that it is fully compatible with the level of description used for other mechanisms (Hodgkin-Huxley currents, calcium diffusion, etc). 2. The mechanism gives EPSP's or IPSP's from a pulse of transmitter. The waveform of these PSP's is very close to EPSP's or IPSP's measured experimentally, and the decay is monoexponential. The user can set all the parameters corresponding to the rising phase, decay, amplitude, etc... (see .mod files) 3. Summation of consecutive PSP's is handled automatically by the mechanism without need for an explicit event cue. 4. Each synapse has a state variable corresponding to the fraction of postsynaptic receptors in the open state. However, the kinetics are first order, and so can be solved exactly. This has the important advantage that it can be fit very easily to experimental recordings (see J. Computational Neurosci. paper). 5. Finally, this mechanism is very fast to compute. It does not require solving any differential equations; at any given time only one exponential is calculated per synapse. Thus, the mechanism is as fast to compute as optimized versions of alpha function-based models. How to run the simulation ------------------------- This directory contains the files necessary to run a simulation of each type of receptor mentioned above. The parameters have been obtained by fitting the model to whole-cell recordings of the various types of synaptic response (see individual .oc and .mod files for details). To compile the demo, NEURON and INTERVIEWS must be installed and working on the machine you are using. Just type "nrnivmodl" to compile the mechanisms given in the mod files (glutamate.mod and gaba.mod are the mechanisms for glutamate and gaba synapses, and HH.mod is the Hodgkin-Huxley kinetics). Then, execute one of the four example files by typing: nrngui <ocfile> where <ocfile> stands for either: demo_ampa.oc : AMPA/Kainate glutamatergic receptors demo_nmda.oc : NMDA glutamatergic receptors demo_gabaa.oc : GABA-A receptors demo_gabab.oc : GABA-B receptors Once the menu and graphics interface has appeared, click on "Init and Run" button to start the simulation... All these simulations were done using the NEURON simulator written by Michael Hines, and which is available freely on internet via anonymous ftp from neuron.neuro.duke.edu:/neuron. For more information about how to get NEURON and how to install it, please refer to the following sites: http://neuron.duke.edu/ http://www.neuron.yale.edu/ For further information, please contact: Alain Destexhe CNRS, UNIC (Bat-33), Avenue de la Terrasse, 91198 Gif-sur-Yvette, France email: Destexhe@iaf.cnrs-gif.fr http://cns.iaf.cnrs-gif.fr 20071004 changed all synapse mod files so that they now use the counter mechanism. -Destexhe. 20110411 changed solve method to cnexp in gabab.mod as per "Integration methods for SOLVE statements" topic in the NEURON forum http://www.neuron.yale.edu/phpBB/viewtopic.php?f=28&t=592 -ModelDB Administrator 20110412 corrected solve method to derivimplicit in gabab.mod (for systems with kinetics)