A High-Bandwidth Dual-Channel Olfactory Stimulator for Studying Temporal Sensitivity of Olfactory Processing.

Animals encounter fine-scale temporal patterns of odorant mixtures that contain information about the distance and number of odorant sources. To study the role of such temporal cues for odorant detection and source localization, one needs odorant delivery devices that are capable of mimicking the temporal stimulus statistics of natural odor plumes. However, current odorant delivery devices either lack temporal resolution or are limited to a single odorant channel. Here, we present an olfactory stimulator that features precise control of high-bandwidth stimulus dynamics, which allows generating arbitrary fluctuating binary odorant mixtures. We provide a comprehensive characterization of the stimulator's performance and use it to demonstrate that odor background affects the temporal resolution of insect olfactory receptor neurons, and we present a hitherto unknown odor pulse-tracking capability of up to 60 Hz in Kenyon cells, which are higher order olfactory neurons of the insect brain. This stimulator might help investigating whether and how animals use temporal stimulus cues for odor detection and source localization. Because the stimulator is easy to replicate it can facilitate generating the same odor stimulus dynamics at different experimental setups and across different labs.