title: Firing clamp: a novel method for single-trial estimation of excitatory and inhibitory synaptic neuronal conductances.
abstract: Understanding non-stationary neuronal activity as seen in vivo requires estimation of both excitatory and inhibitory synaptic conductances from a single trial of recording. For this purpose, we propose a new intracellular recording method, called "firing clamp." Synaptic conductances are estimated from the characteristics of artificially evoked probe spikes, namely the spike amplitude and the mean subthreshold potential, which are sensitive to both excitatory and inhibitory synaptic input signals. The probe spikes, timed at a fixed rate, are evoked in the dynamic-clamp mode by injected meander-like current steps, with the step duration depending on neuronal membrane voltage. We test the method with perforated-patch recordings from isolated cells stimulated by external application or synaptic release of transmitter, and validate the method with simulations of a biophysically-detailed neuron model. The results are compared with the conductance estimates based on conventional current-clamp recordings.
authors.affiliation: Computational Physics Laboratory, Division of Plasma Physics, Atomic Physics and Astrophysics, A.F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences St. Petersburg, Russia.
authors.forename: Anton V
authors.initials: AV
authors.lastname: Chizhov
authors.affiliation: Section for Physiology, Department of Integrative Medical Biology, Umea University Umea, Sweden.
authors.forename: Evgenya
authors.initials: E
authors.lastname: Malinina
authors.affiliation: Section for Physiology, Department of Integrative Medical Biology, Umea University Umea, Sweden ; Department of Neurodynamics and Neurobiology, Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod, Russia.
authors.forename: Michael
authors.initials: M
authors.lastname: Druzin
authors.affiliation: Neurophysiology and New Microscopies Laboratory, INSERM U603 - CNRS UMR 8154, Université Paris Descartes Paris, France.
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Graham
authors.affiliation: Section for Physiology, Department of Integrative Medical Biology, Umea University Umea, Sweden.
authors.forename: Staffan
authors.initials: S
authors.lastname: Johansson
keywords: dynamic clamp; firing-clamp; synaptic conductance estimation
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