Real Time NEURON Simulation for Experimental Applications

The goal of this proposal is to combine the power of the NEURON mathematical modeling software with the Cybercyte “plug and play” dynamic clamp system. Our product will enable all neuronal electrophysiologists to be able to perform sophisticated NEURON model based dynamic clamp experiments, without any requirement for programming, engineering, or mathematical modeling skills. Our product is an integrated package of hardware and software specifically for neuroscience applications, focusing on the specific stability and reliability needed for routine neuronal electrophysiology and the large array of ion channels found in the nervous system. The four aims of this project are: Aim 1. Implement and Test Electronic Expression Mode. In this aim, the patch clamp amplifier is used in current clamp mode to run cell-based action potentials from live cells, augmented with computer models of specific channels. Artificial ion channels generated by computer models are used to inject an equivalent current to mimic the effects of channel mutations, gain of function, state dependent drug binding etc., to reveal their mechanisms of action on the excitability of real neurons. This can be thought of as an inexpensive “short cut” to the painstaking process of generating genetic models of ion channels and other electrophysiological models. Aim 2. Implement and Test Synthetic Cell Mode. In synthetic cell mode, all of the component currents, except for the one of interest, are modelled, along with membrane action potentials. The current of interest is then generated in, for example, an HEK cell expressing the channel of interest and controlled by a voltage-clamp amplifier. The command input to the voltage clamp is the simulated action potential from the dynamic clamp system with the synthetic cell. For example, real drugs can be added to the cloned channel of interest or the consequences of a real kinetic mutation can be analyzed. Aim 3. Implement and Demonstrate Cell Coupling Mode. Cell coupling mode was arguably the first form of dynamic clamp invented. Originally it used analog circuitry to mimic gap junctional resistance between cells. With NEURON, we can implement complex forms of cell to cell coupling, including synaptic transmission and interneurons. Aim 4. Implement and Test Diagnostics and Experimental Safeguards. A major limitation of dynamic clamp applications in research and development, particularly in commercial applications, is the difficulty in maintaining quality control. This aim helps automate the process of quality control to make the system accessible to non- specialist users.Completion of these aims will result in a commercial advanced dynamic clamp system with an interface to NEURON, which is powerful, reliable, but plug and play to install, and simple to use.