Average fluorescence changes measured from tufts 1-3 as indicated in the image of labelled tufts (see above). Time is taken as the time at which the line scan was in the center of tuft in order to compensate for scan delay between line 1 and 256 in each image. fluorescence is normalized to the average fluorescence in the 6 images prior to application of a brief puff of methyl salicylate odour to the nose. Note the differences in onset time and time to peak change in each 'tuft".