The ability of experimentalists to perturb biological systems has traditionally been limited to rigid pre- programmed protocols or more flexible, but reflex constrained, operator-controlled protocols. In contrast, """"""""real-time control"""""""" allows the researcher to dynamically probe a biological system with parameter perturbations that are calculated functions of instantaneous system measurements, thereby providing the ability to address diverse unanswered questions that are not amenable to traditional approaches. Real-time control applications are abundant throughout biological research, including, for example, dynamic probing of ion-channel function, control of cardiac arrhythmia dynamics, and control of deep-brain stimulation patterns. Unfortunately, for a number of technical reasons, real-time control is not possible with standard computer operating systems and software. To circumvent these limitations, we have developed a fast and highly versatile real-time biological experimentation system known as Real-Time eXperiment Interface (RTXI), which is based on Real-Time Linux, is open source and free, and has been adopted by many prominent laboratories. Although RTXI is already being used successfully for a range of experiments, there remain important development avenues that would significantly expand its functionality and broaden its utility for the biological research community, and which therefore comprise the specific aims of this renewal proposal: 1. To periodically update RTXI's base code and plugins so that RTXI remains current. 2. To incorporate several new features that will facilitate the ongoing experiments of RTXI end users. 3. To broaden RTXI's real-time experiment application space to support two techniques for which real- time control is well-suited: optical mapping and two-photon imaging. 4. To broaden the experiment-design options, beyond the current options of direct source-code or script editing, by adding block-diagram and drag-and-drop visual-design tools. 5. To improve usability through the development of professional documentation and a user tutorial. By accomplishing these goals, this project will open new avenues of research and enable novel insights that are unavailable with traditional experimentation approaches.

Public Health Relevance

(Using no more than two or three sentences, describe the relevance of this research to public health.) Traditional experimentation protocols are not always capable of fully probing the mechanisms of complex biological systems. We have developed a free, open-source software system, known as Real-Time eXperiment Interface (RTXI), that enables experimentalists to perform protocols that are adapted on-the-fly to maximize or optimize information acquisition during the course of an experiment. This project, which aims to expand the functionality of RTXI in significant ways, will further the abilities of biological scientists to use such protocols to learn important information about biological systems ranging from the heart to the brain.

National Institute of Health (NIH)
National Center for Research Resources (NCRR)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-NT-K (01))
Program Officer
Friedman, Fred K
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Weill Medical College of Cornell University
Internal Medicine/Medicine
Schools of Medicine
New York
United States
Zip Code
Patel, Yogi A; George, Ansel; Dorval, Alan D et al. (2017) Hard real-time closed-loop electrophysiology with the Real-Time eXperiment Interface (RTXI). PLoS Comput Biol 13:e1005430
Ortega, Francis A; Butera, Robert J; Christini, David J et al. (2014) Dynamic clamp in cardiac and neuronal systems using RTXI. Methods Mol Biol 1183:327-54
Broicher, Tilman; Malerba, Paola; Dorval, Alan D et al. (2012) Spike phase locking in CA1 pyramidal neurons depends on background conductance and firing rate. J Neurosci 32:14374-88
Lillis, Kyle P; Kramer, Mark A; Mertz, Jerome et al. (2012) Pyramidal cells accumulate chloride at seizure onset. Neurobiol Dis 47:358-66
Kispersky, Tilman J; Fernandez, Fernando R; Economo, Michael N et al. (2012) Spike resonance properties in hippocampal O-LM cells are dependent on refractory dynamics. J Neurosci 32:3637-51
Economo, Michael N; White, John A (2012) Membrane properties and the balance between excitation and inhibition control gamma-frequency oscillations arising from feedback inhibition. PLoS Comput Biol 8:e1002354
Fernandez, Fernando R; Broicher, Tilman; Truong, Alan et al. (2011) Membrane voltage fluctuations reduce spike frequency adaptation and preserve output gain in CA1 pyramidal neurons in a high-conductance state. J Neurosci 31:3880-93
Kispersky, Tilman J; Economo, Michael N; Randeria, Pratik et al. (2011) GenNet: A Platform for Hybrid Network Experiments. Front Neuroinform 5:11
Joseph, Laveeta; Butera, Robert J (2011) High-frequency stimulation selectively blocks different types of fibers in frog sciatic nerve. IEEE Trans Neural Syst Rehabil Eng 19:550-7
Kispersky, Tilman; White, John A; Rotstein, Horacio G (2010) The mechanism of abrupt transition between theta and hyper-excitable spiking activity in medial entorhinal cortex layer II stellate cells. PLoS One 5:e13697

Showing the most recent 10 out of 24 publications