Influence of Ionic Conductances on Spike Timing Reliability of Cortical Neurons for Suprathreshold Rhythmic Inputs

• Published in: Journal of neurophysiology Vol. 91; no. 1; pp. 194 - 205
• Main Authors: Schreiber, Susanne, Fellous, Jean-Marc, Tiesinga, Paul, Sejnowski, Terrence J
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.01.2004
• Subjects: Animals; Cerebral Cortex - cytology; Cerebral Cortex - physiology; Electric Stimulation; Electrophysiology; Humans; Ion Channels - physiology; Models, Neurological; Neural Conduction - physiology; Neurons - physiology; Oscillometry; Reaction Time; Reproducibility of Results; Synaptic Transmission; Time Factors
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00556.2003

1 Sloan-Swartz Center for Theoretical Neurobiology, Salk Institute, La Jolla, California 92037 2 Howard Hughes Medical Institute, and Computational Neurobiology Lab, Salk Institute, La Jolla, California 92037 3 Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 4 Department of Biology, University of California San Diego, La Jolla, California 92037 5 Institute for Theoretical Biology, Humboldt-University Berlin, D-10115 Berlin, Germany Submitted 9 June 2003; accepted in final form 15 September 2003 Spike timing reliability of neuronal responses depends on the frequency content of the input. We investigate how intrinsic properties of cortical neurons affect spike timing reliability in response to rhythmic inputs of suprathreshold mean. Analyzing reliability of conductance-based cortical model neurons on the basis of a correlation measure, we show two aspects of how ionic conductances influence spike timing reliability. First, they set the preferred frequency for spike timing reliability, which in accordance with the resonance effect of spike timing reliability is well approximated by the firing rate of a neuron in response to the DC component in the input. We demonstrate that a slow potassium current can modulate the spike timing frequency preference over a broad range of frequencies. This result is confirmed experimentally by dynamic-clamp recordings from rat prefrontal cortical neurons in vitro. Second, we provide evidence that ionic conductances also influence spike timing beyond changes in preferred frequency. Cells with the same DC firing rate exhibit more reliable spike timing at the preferred frequency and its harmonics if the slow potassium current is larger and its kinetics are faster, whereas a larger persistent sodium current impairs reliability. We predict that potassium channels are an efficient target for neuromodulators that can tune spike timing reliability to a given rhythmic input. Address for reprint requests and other correspondence: T. J. Sejnowski, Computational Neurobiology Laboratory, The Salk Institute, 10010 N. Torrey Pines Road, La Jolla, CA 92037 (E-mail: terry{at}salk.edu ).