1976 Volume 79 Issue 1 Pages 70-75
Recording of odorant evoked response from the human scalp has been reported by Finkenzeller (1966), Allison (1967), Giesen (1970) and Herberhold (1972). It is technically difficult in the chemical senses.
This report presents two methods of odorant presentation in human odorant evoked response.1) A teflon tube was inserted into the olfactory region and the odorous substance was blasted by activating the electromagnetic valve. The electromagnetic valve was connected with the trigger circuit of an analog averager, for stimulus-locked aveaging. Twenty responses were averaged.
2) The phototransistor and a light source were set up in the rectiline at the nostril The filterpaper dipped in the odorous substance was put in between the phototransistor and the light source during the inspiratory phase. The phototransistor was connected with the trigger circuit of the analog averager. When the light source was interrupted by the filter paper, a trigger pulse to the analog averager was activated. Twenty responses were averaged.
Results were as follows:
1) By the first method, the average evoked response to the odorant stimulation (dl-camphor) was recorded, and the response was obtained even in the case of no odorant stimulation. The response was consisted of a wave with peak latency of 200 msec, in both experiments.
It was supposed that this average evoked response was the auditory response to the click produced by the electromagnetic valve, or to the blast by opening of the valve.
2) By the second method, the average evoked response to the odorant stimulation (dl-camphor)has been recorded, and it was consisted of a wave with peak latency of 400 msec.
The click and pressure sensation on the mucous membrane in the olfactory region by the blast are supposed to give some effects on EEG.
The second method has advantage over the first one to exclude these adverse effects.
