Reconstruction of firing rate from Ca2+ fluorescence signal

DAMIAN ERNESTO OLIVA , DANIEL TOMSIC , ALEJANDRO DELORENZI

Cordoba

Congreso; SAN- Taller Argentino de Neurociencias 2012; 2012

SAN

Sensory SystemsPoster Number 193 / Session IIReconstruction of firing rate from Ca2+ fluorescence signalDamian Ernesto Oliva , Daniel Tomsic , Alejandro Delorenzi 1 Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes,Roque Sáenz Peña 352, Bernal (B1876BXD), Buenos Aires, Argentina2 Laboratorio de Neurobiología de la Memoria, Departamento Fisiología,Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales,Universidad de Buenos Aires, IFIBYNE-CONICET, Pabellón 2 CiudadUniversitaria (1428),Ciudad de Buenos Aires, Argendoliva@unq.edu.arIn this study, we present a simple algorithm for the reconstruction of firing ratefrom Ca2+ fluorescence signal. The basic idea of this method is that actionpotentials (APs) open voltage-gated Ca2+ channels and produce unitary Ca2+transients with a fast rise and a stereotyped, usually exponential, decay. Duringtrains of APs, individual transients summate and generate complex temporalvariations in Ca2+ concentration. These processes can be approximated by afirst order linear system and the Ca2+ signal can be generated by a convolutionof the AP train with the waveform of the unitary Ca2+ transient. Wesimultaneously recorded voltage and fluorescence signal for different giantneurons in the crab Neohelice granulata and investigated whether a neurondischarge can be extracted with reasonable precision from single trials usingdF/F recorded. To quantify the accuracy of the proposed algorithm, we calculatethe cross-correlation between the measured and the predicted neuronal firingrate. We obtained maximum correlation values above 0.9 in all neurons tested.We conclude that this method of firing rate reconstruction, from spiking neurons,is simple and accurate.