Figure 2.

Variability and consistency in OSN responses. A, Electrophysiological responses of eight [Or42a-Gal4/UAS-Or83b; Or83b ^−/−] larvae to stimulation with butanol and propyl acetate. The order of presentation was rotated from larva to larva; there was a 2 min interstimulus interval. Only a single responding OSN was detected in each larva. Controls demonstrated that both OrX-Gal4 and UAS-Or83b larvae showed normal, wild-type multiunit responses (data not shown). B, Electrophysiological responses of a single OSN in a [Or42a-Gal4/UAS-Or83b; Or83b ^−/−] larva which was presented twice with propyl acetate and twice with butanol with a 2 min interstimulus interval. The Or42a OSN responded both times to propyl acetate but clearly failed to respond to the first presentation of butanol.