Spike timing precision of pheromone sensitive neurons in the antennal lobe of the moth Agrotis ipsilon
Résumé
In order to locate their mates, male moths have to detect and interpret specific blends of odours -pheromones- released by the females and dispersed by the wind. In male moths, sex pheromones are detected by specialized olfactory receptor neurons situated in cuticular sensilla on the antennae and processed within the Macro-Glomerular Complex (MGC) of the antennal lobe. In this study, we show a detailed analysis of the spike timing precision in pheromone sensitive neurons in the antennal lobe of the moth Agrotis ipsilon. We performed simultaneous extracellular recordings within the MGC from several neurons in vivo and identified individual spike trains using spike sorting algorithms. To analyse spike timing precision, a statistical tool was developed to segment and characterize individual spike trains. Our analysis reveals that MGC neurons have a stereotyped and synchronized response in the presence of pheromones. From repeated measurements of single odor stimulations, we show that the response is both precise (temporal jitter of spikes over trials < 4ms) and robust (probability of loosing spikes over trials < 0.1). Moreover, experiments conducted using different stimulation protocols with pheromone pulses reveal how the temporal pattern of a response to previous puffs could affect the responses to the following ones. Based on the stereotyped response and its extreme precision we draw conclusions on intrinsic properties of MGC neurons.