Optical recordings from the human nasal mucosa in response to olfactory stimulation

Using the intrinsic optical signal the present study aimed to investigate changes in blood flow at the nasal epithelium in response to specific olfactory stimulation. Recording equipment included an endoscope, a CCD camera, and a light source of 617 nm. Two concentrations of the specific olfactory stimulant H2S (2.8 and 5.6 ppm), generated by a computer-controlled olfactometer, were used for olfactory stimulation. Eight healthy normosmic volunteers participated. Using 5.6 ppm H2S stimuli, responses were typically recorded from the olfactory cleft, middle turbinate, and middle meatus while responses were less pronounced for 2.8 ppm H2S stimuli. Response areas were significantly larger for the 5.6 ppm H2S stimuli. While further experiments are needed, recordings of the intrinsic optical signal may be used to obtain responses from the nasal cavity to specific olfactory stimuli.