Human Evoked Response and EEG Changes to Odorant Stimulation

点击翻译按钮获取中文摘要

The summary of the results of our study which took place from 1987 to 1988 are described. An apparatus was developed allowing control of stimulation for recording odorant evoked response from the human scalp. The characteristics of the apparatus were as follows. 1) A sensor was attached to the nostril allowing translation of the subject's respiration into electrical signals. 2)The period and timing of odorant stimuli were adjustable allowing stimuli to be given synchronous with respirations. 3)The intervals of odorant stimulation could be arbitrarily selected to occur every 1 to 9 respiration(s) allowing avoidance of adaptation to the given odor.Odorant evoked responses were obtained in 84.6% of the 26 normal subjects tested. The responses were classified into three types, with a peak latently of 300 msec, 700 msec, and both latencies. The scalp distribution of responses revealed that the region of high potentials were widely spread over the vertex, and that latency with distance towards the occipital region. A response was not recordable from a patient with anosmia. However, more study is necessary to apply this finding to objective olfactometry because that the responses were not recorded in all normal subjects.The EUG changes during odorant stimulation were investigated using the technique of SPN (significance probability mapping). The findings allowed that alpha _1, delta and rheta waves were decreased in the occipital region and that alpha_2 wave was increased at the frontal region. These EEG changes may reflect activity of the olfactory central system in the frontal region.