PMC

EAG concentration-response (mean ± SE, n = 10) curves of Cnaphalocrocis medinalis antennae to methyl salicylate, heptanol, linalool, cyclohexanol, and 2-heptanone for one-day-old males. High quality figures are available online.

(A) Odor-induced activation maps for AA, carvone, heptanol, heptanone, hexanal, and MV. Top row: the dorsal region of the OB. Bottom row: the lateral region of the OB (1 animal, average of 3 trials). (B) Spatial odor map correlations between response amplitudes and the location along each spatial dimension of all identified glomeruli. Left: dorsal region of the OB. Right: the lateral region of the OB. Error bars are SEM (AA, heptanol, and hexanal 5 animals; all others 6 animals). (C) Across-glomerular response pattern similarities, assessed by Pearson correlations across glomerular response amplitudes. Left: for the dOB. Right: for the lOB (AA, heptanol, and hexanal 5 animals; all others 6 animals). (D) Average z-scores of glomerular response amplitudes (relative to pre-odor breathing response amplitudes). z-Scores are organized relative to MV. Left represents the dorsal region of the OB. Right: the lateral region of the OB (1 animal, 3 trials, same trials as shown in 2A). Underlying data for this figure can be found in . AA, amyl acetate; dOB, dorsal olfactory bulb; lOB, lateral olfactory bulb; MV, methyl valerate; OB, olfactory bulb.

Relative EAG responses (mean ± SE, n = 15) of Cnaphalocrocis medinalis to different compounds. Compounds numbers are: 1. CK; 2. cyclohexanol; 3. linalool; 4. tetradecane; 5. hexadecane; 6. heptadecane; 7. octadecane; 8. nonadecane; 9. eicosane; 10. henicosane; 11. (-)-α-cedrene; 12. nerolidol; 13. cedrol; 14. (Z)-farnesene; 15. ter- pinene-4-ol; 16. α-terpineol; 17. α-terpinene; 18. β-myrcene; 19. sabinene; 20. p-cymene; 21. methyl benzoate; 22. (-)-trans- caryophyllene; 23. dodecanal; 24. methyl salicylate; 25. γ-terpinene; 26. octane; 27. 2-heptanone; 28. N -phenyl-1-naphthylamine; 29. R-(+)- limonene; 30. benzaldehyde; 31. cis-2-penten-1-ol; 32. (1R)-(+)-a- pinene; 33. hexanal; 34. lonone; 35. heptanol; 36. (Z)-3-hexen-1-ol; 37. (E)-2-hexen-1-ol; 38. (E)-2-hexenal; 39. (Z)-2-hexen-1-ol. High quality figures are available online.

Schematics of delivery routes and experiment procedures. (a) The study tests whether rats can recall a learned association between a purely retronasal odorant and tastant when subsequently exposed to the odorant orthonasally. (b) Experiment 1 consists of the retronasal conditioning phase and orthonasal testing phase. After being pretrained to perform the orthonasal discrimination task with 2 odor sets, rats were transferred to 2 days of retronasal conditioning and 2 days of orthonasal testing (150 trials per session, 1 session per day) (lim, limonene; EMB, ethyl 2-methylbutyrate; MV, methyl valerate; Hex, hexanone; PP, propyl propionate; MB, methyl benzoate; AA, amyl acetate; Citron, citronelle; Hep, heptanol). (c) During a retronasal conditioning trial, a rat receives clean air when nose poking in the odor port and licks the spout twice to receive odor+taste solution. Orthonasal odorants are removed via a concentric vacuum. (d) A rat is tested on the orthonasal discrimination task where odorized air is delivered, and the rat chooses to either lick or not lick for the reinforcer solution associated with the odorant. (e) Experiment 2 examines rats’ ability to discriminate retronasal odorants. Dispensing of odorized solution is initiated by one lick, and if the rat continues licking (more than 2 licks), the sweet or bitter reinforcer is delivered.