Fig. 2. A linked gas chromatography—single cell recording from an antennal sensillum (S5) containing two olfactory receptor neurones (ORNs). (A) Gas chromatogram (GC) of a papaya head-space sample and the corresponding single-cell recording (SC), presented in histogram form (spikes s^-1; vertical bar, 25 spikes s^-1; horizontal bar, 1 min). The two ORNs present are sensitive to different components in the papaya volatile collection. The S5A neurone responds primarily to butyl butyrate (5), but also to 1-hexanol (2) and isovaleric acid (4). The S5B neurone responds strongly to isoamyl acetate (3) and moderately to butyl acetate (1). (B) Action potential amplitudes recorded during the above experiment. The distribution of amplitudes from the recording shows the clear physiological separation of the two ORNs (S5A and S5B).