title: Simultaneous Bayesian Estimation of Excitatory and Inhibitory Synaptic Conductances by Exploiting Multiple Recorded Trials.
abstract: Advanced statistical methods have enabled trial-by-trial inference of the underlying excitatory and inhibitory synaptic conductances (SCs) of membrane-potential recordings. Simultaneous inference of both excitatory and inhibitory SCs sheds light on the neural circuits underlying the neural activity and advances our understanding of neural information processing. Conventional Bayesian methods can infer excitatory and inhibitory SCs based on a single trial of observed membrane potential. However, if multiple recorded trials are available, this typically leads to suboptimal estimation because they neglect common statistics (of synaptic inputs (SIs)) across trials. Here, we establish a new expectation maximization (EM) algorithm that improves such single-trial Bayesian methods by exploiting multiple recorded trials to extract common SI statistics across the trials. In this paper, the proposed EM algorithm is embedded in parallel Kalman filters or particle filters for multiple recorded trials to integrate their outputs to iteratively update the common SI statistics. These statistics are then used to infer the excitatory and inhibitory SCs of individual trials. We demonstrate the superior performance of multiple-trial Kalman filtering (MtKF) and particle filtering (MtPF) relative to that of the corresponding single-trial methods. While relative estimation error of excitatory and inhibitory SCs is known to depend on the level of current injection into a cell, our numerical simulations using MtKF show that both excitatory and inhibitory SCs are reliably inferred using an optimal level of current injection. Finally, we validate the robustness and applicability of our technique through simulation studies, and we apply MtKF toin vivodata recorded from the rat barrel cortex.
authors.affiliation: Neurosciences and Mental Health, Department of Physiology and the Institute of Biomaterials and Biomedical Engineering, University of Toronto, The Hospital for Sick ChildrenToronto, ON, Canada; RIKEN Brain Science InstituteSaitama, Japan.
authors.forename: Milad
authors.initials: M
authors.lastname: Lankarany
authors.affiliation: Center for Neuroscience, Biosciences Division, SRI International Menlo Park, CA, USA.
authors.forename: Jaime E
authors.initials: JE
authors.lastname: Heiss
authors.affiliation: Department of Neurobiology, Weizmann Institute of Science Rehovot, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Lampl
authors.affiliation: RIKEN Brain Science Institute Saitama, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Toyoizumi
keywords: Kalman filter; barrel cortex; current clamp; excitatory and inhibitory synaptic inputs; in vivo; synaptic conductance