Temporal integration of nasal irritation from ammonia at threshold and supra-threshold levels.
Two experiments examined integration of perceived irritation over short-term (approximately 100-4000 ms) delivery of ammonia into the nasal cavity of human subjects. Experiment 1 examined trade-offs between time and concentration at threshold level by means of nasal lateralization, a common measure of irritation threshold. Within experimental sessions, the duration of a fixed-concentration stimulus varied to determine the shortest, detectable pulse. Subjects could lateralize increasingly weaker concentrations with longer stimulus presentations. Experiment 2 examined an analogous trade-off for supra-threshold irritation. Subjects rated irritation from presentations of ammonia that varied both in concentration and in duration. Rated intensity for a given concentration increased with stimulus duration. Hence integration occurred at both threshold and supra-threshold levels. However, more than a twofold increase in duration was required to compensate for a twofold decrease in concentration to maintain threshold lateralization or a fixed level of perceived intensity. These results suggest that an imperfect mass-integrator model may be able to describe short-term integration of nasal irritation from ammonia at both the threshold and supra-threshold levels.
Wise
Paul M
PM
Monell Chemical Senses Center, Philadelphia, Pennsylvania, 19104-3308, USA. pwise@monell.org
Canty
Thomas M
TM
Wysocki
Charles J
CJ
D000328:Adult; D000641:Ammonia / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007509:Irritants / Q000633:toxicity*; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000187:drug effects*; D012684:Sensory Thresholds
D007509:Irritants; D000641:Ammonia