title: Estimation of the individual firing frequencies of two neurons recorded with a single electrode.
abstract: When monitoring neurons with a single extracellular electrode, it is common to record action potentials from different neurons. A recurring problem with such recordings is to identify which neuron is active. Sorting spikes into separate classes is possible if each neuron discharge spikes differing by their shapes and sizes. However, this approach is not applicable when the spikes are indistinguishable. In this paper, we develop a method for estimating the respective firing frequencies of two neurons, producing indistinguishable spikes. It is based on the fact that, when a neuron fires a spike, there is an interval of time during which the probability of generating a second spike is very low. If a spike occurs during this 'silent period', it is likely to be generated from another neuron and the number of occurrences of such 'doublets' can be used to estimate the respective frequencies of two spike trains. We demonstrate here that a simple relation holds between the frequency of doublets d, the respective frequencies of the two neurons A and B, fA and fB, and a chosen value Delta shorter than the silent period, d=2fAfBDelta. This relation holds for a wide class of firing processes. We used this method to analyze responses from Drosophila taste sensilla. We first checked if the method was consistent with results obtained with stimuli that elicit responses of two taste neurons firing distinguishable spikes. We then applied this method to the study of a pair of taste neurons involved in the coding for salt taste in Drosophila melanogaster.
authors: Unité de Phytopharmacie et Médiateurs chimiques, INRA, F-78026 Versailles Cedex, France.
authors: Nicolas
authors: N
authors: Meunier
authors: Frédéric
authors: F
authors: Marion-Poll
authors: Petr
authors: P
authors: Lansky
authors: Jean Pierre
authors: JP
authors: Rospars
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D004331:Drosophila melanogaster / Q000187:drug effects / Q000502:physiology; D004566:Electrodes; D004594:Electrophysiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D015203:Reproducibility of Results; D012107:Research Design; D012492:Salts / Q000494:pharmacology; D013649:Taste / Q000187:drug effects / Q000502:physiology; D013652:Taste Threshold; D013997:Time Factors
chemical_list: D012492:Salts