Odors were delivered using an 8-channel air-dilution olfactometer based on the design of Lorig et al. (1999), and as previously used and described in Kareken et al. (2004). Briefly, odor delivery was computer-controlled using Dasylab® software (IO-Tech, Inc., Cleveland, OH) and a Personal Daq/56 module (IOTech, Inc., Cleveland, OH). Air was delivered to the subject’s nose via a small polytetrafluoroethylene tube at 2.0 liters per minute (lpm).This airstream was composed of a constant 1.0 lpm stream into which was injected either a second 1.0 lpm stream of clean air (between odorant stimulation), or an airstream that had been passed through one of 6 glass vials containing the odorants used in the study. In this manner, the odorants were delivered without any change in flow rate or somatosensory stimulation at the nose.
