Burghart GmbH, Wedel, Germany) through a Teflon™ tube inserted approximately 1 cm into the naris. Stimulus duration was 200 ms (not more than 50 ms rise time according to manufacturer specification). For any given session, the air stream at the exit of the olfactometer had a constant flow rate (about l/min), temperature (the measured range was 40° –44 °C at the olfactometer’s head to approximately 37 °C body temperature when entering the nasal cavity), and relative humidity (above 80%). White noise of approximately 75 dB SPL was presented binaurally via Telephonics TDH-49P earphones to preclude hearing the switching valves.
