Fig. 5.
Chemical tuning of individual glomeruli to aliphatic aldehydes. a, Optical response plotted as a function of the carbon chain length of the odorant. Each plot represents one of the glomeruli of Figure 4 and contains four curves measured at increasing odor concentrations D = 0.0001, 0.001, 0.01, and 0.1. The vertical axis is scaled for each glomerulus to the maximum response observed. b, Response as a function of odor concentration, D, for two of the glomeruli in a. Bold lines are measurements for the six different odorants, scaled to the maximal response; thin lines are fits of the first-order binding model (Eq. 1) to the data. Note that the model contains only seven parameters for fitting 28 data points. c, Comparison of the actual response and the response predicted by Equation 1 for all 10 glomeruli in a. Dotted line is the identity. Colors indicate odorants as in b.d, Sensitivity (solid line) plotted as a function of the odorant's carbon chain length, for each of the glomeruli in a. Sensitivity is the reciprocal of the half-saturating concentration, determined from the fits of Equation 1in b. Shown for comparison is the response measured at high concentration (D = 0.1, froma), normalized to the same maximum value (dotted line).