Heterogeneity and Convergence of Olfactory First-Order Neurons Account for the High Speed and Sensitivity of Second-Order Neurons
Figure 2
Pheromone-evoked spiking activities are qualitatively and quantitatively different in ORNs and PNs.
In this and all following figures ORNs are shown in blue and PNs in red. (A) Phasic-tonic activity in a single ORN at various doses C of Z7-12∶Ac from -1 to 4 log ng (bar: stimulus duration, 200 ms). Schematic representation based on spike sorting. Hexane (hex) used as control. Vertical line at Tt = 180±13 ms (mean ± SD) indicates mean time of arrival of stimulus on antenna. (B) Multiphasic activity in a PN at doses from -3 to 1 with repetitions. Same representation as in (A). (C) Instantaneous firing rates estimated with a 50 ms Gaussian kernel (see Methods) of spike trains shown in (A). (D) Instantaneous firing rates of the trains shown in (B). (E) Comparison of average instantaneous firing rates of ORNs and PNs recorded at doses -1, 0 and 1 log ng. (F) Firing rate F versus latency L pairs from the same pheromone-evoked response for all ORNs (blue) and PNs (red) recorded at dose C = −1 log ng (responses significantly different shown as filled circles; all other figures show only responses significantly different from spontaneous activity).