Human Evoked Response and EEG Changes to Odorant Stimulation

本文对1987年至1988年的研究结果进行了总结。开发了一种装置，可以控制刺激，记录人类头皮的气味诱发反应。该仪器的特点如下。一个传感器连接在鼻孔上，可以将受试者的呼吸转换成电信号。2)气味刺激的周期和时间是可调节的，使刺激与呼吸同步。3)气味刺激的间隔可以任意选择为每1到9次呼吸(s)，以避免对给定气味的适应。在26名正常受试者中，有84.6%的人产生了气味诱发反应。响应分为三种类型，峰值潜伏期为300毫秒，700毫秒，两种潜伏期都有。头皮反应分布表明，高电位区域广泛分布于顶点，且潜伏期随距离向枕区延伸。嗅觉缺失患者的反应不可记录。然而，需要更多的研究将这一发现应用于客观嗅觉测定，因为并不是所有正常受试者的反应都被记录下来。采用显著性概率映射（SPN）技术研究了气味刺激时EUG的变化。结果表明，α _1、δ和δ波在枕区减弱，α _2波在额区增强。这些脑电图变化可能反映了额叶区嗅觉中枢系统的活动。

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.