Fig. 6.

Effect of the duration of the oscillation period of the gain values of ON ORNs (orange) and OFF ORNs (blue) for the instantaneous odorant concentration and its rate of change. a In both types of ORNs, the gain for the instantaneous odorant concentration decreases, sign ignored, with increasing duration of the oscillation period. b Conversely, the gain of both ORNs for the rate of concentration change increases when the period length increases, with due consideration of the sign. The negative gain values are due to the downward direction of the concentration change, resulting in an increase in impulse frequency of the OFF ORN. Mean values and standard deviation attained from 16 ON and 16 OFF ORNs are indicated. The number of measurements, n, used to determine gain is 16 for the oscillation periods in the range between 3 and 120 s, n = 14 for the 180-s period, n = 12 for the 240-s period, n = 10 for the 300-s period, and n = 8 for the 360-s period. Differences in gain values between adjoining oscillation periods were tested for statistical significance by the paired Student’s t test, *P < 0.05. For periods with n < 14, significance was not tested.

Adapted from Burgstaller and Tichy (2012)