Interpolating Maps between Neural Response Spaces for Chemosensing with Fruit Fly Antenna Sensors

The odorant receptor neurons on the fruit fly antenna are highly sensitive to a broad range of chemicals. A compound signal of receptor activity on the antenna can be read out in real time with functional neuroimaging, and individual receptor responses to hundreds of odorants are available in a database. Utilizing the fruit fly antenna as chemosensor enables applications ranging from biomarker detection to identification of unknown chemicals in samples. Here, we propose to connect neural response spaces, mapping odorant responses from one fly to another and to database space. A map is defined exactly for reference odorants common to both subject and target space, while the map for the remaining odorants is estimated based on radial basis function interpolation. On a data set with chemically diverse odorants, mapping to another antenna allows identifying unlabelled subject space odorants by the proximity of their mapped position to labelled odorants in target space. Furthermore, mapping from antenna to database space predicts the individual receptor responses significantly better than a random baseline model, suggesting that receptor responses can be inferred from the compound antenna signal given a sufficiently dense net of reference odorants to support the map.