Combinatorial coding of odor identity and intensity


September 16, 2015 - 1:00pm
NW 243
About the Speaker
Guangwei Si and Jess Kanwal (Samuel Lab)

We perceive the structure of lights and sounds based on the combinations of wavelengths in their respective energy spectra. This perceptual characteristic is detected first by sensory receptors tuned to individual wavelength/frequency of a stimulus. But what metric describes an odor, and how is it encoded within olfactory receptors? We are using in vivo calcium imaging to map the response profile of the 21 olfactory receptor neurons (ORNs) of the Drosophila larva to a panel of odorants. We find that subgroups of co-activated ORNs respond to odorants sharing a common chemical structure. Furthermore, odor combinations can be mapped onto a low dimensional surface with axes representing odor structure. Measurement of the temporal response of ORNs reveals that receptor neurons exhibit overlapping odor-response curves, which together expand the range of odor concentrations that can be detected by the olfactory system. These experiments describe the spatial and temporal tuning of individual receptors constituting the entire olfactory input in a Drosophila larva.