认知与发展心理学研究室知识库

在嗅觉感知的特征中，气味的强度和唤醒度由于较高的相关常常被研究者替换使用，实际上这两个概念阐述的是否是相同的知觉表征还尚未有定论。本论文针对嗅觉强度和唤醒度研究领域中的不足，提出三项研究，分别探讨气味强度的加工机制以及气味强度和唤醒度感知之间的关系，具体内容如下：

（1）研究一主要探究鼻内纯净空气流对气味强度感知的影响。采用行为实验和药物实验相结合的范式，通过操纵对侧鼻腔内空气流的物理量大小或者被试对空气流的感知强弱来考察对侧鼻孔的纯净空气流本身对单鼻气味强度加工的影响。结果发现气味强度感知会加权个体对空气流的感知，这表明在嗅觉领域强度感知是一种跨模态的加工，整合了嗅觉系统和三叉神经系统的信息。

（2）研究二主要从神经生理和行为角度来考察在嗅觉感知中唤醒度和强度之间的关系。通过匹配气味的愉悦度和强度来考察气味在唤醒度感知上的差异，使用静息态脑电图技术来测量不同气味所引起的大脑神经节律的差异，并引入注意瞬脱的任务范式检验不同气味条件下个体的行为表现。结果发现被感知为唤醒度更高的气味不仅可以引起高唤醒度状态的神经振荡模式，还可以提升个体在注意瞬脱任务中的表现。

（3）研究三进一步考察不同唤醒度气味影响注意瞬脱任务表现的神经机制。采用脑电图技术同步记录不同气味情境下注意瞬脱任务中被试在视觉刺激呈现之前以及视觉刺激呈现过程中的神经活动，考察不同气味条件下被试完成任务过程中神经振荡活动的差异。结果发现被知觉为唤醒度更高的气味可以通过增加被试在目标出现前的准备，减少大脑对刺激呈现频率的神经卷入和增加对目标刺激的注意资源分配来提升个体的任务表现。

Odor intensity and arousal are always alternative because of their high correlation although whether they refer to the same perceptual representation is unclear. This thesis attempts to explore the processing mechanism of intensity and arousal as well as the relationship between them in the olfactory sensory system. Specifically,

(1)Study I explored the influence of pure airflow on unilateral odor intensity perception by manipulating the physical amount or just the sensation of pure airflow in the other nostril in behavioral and drug experiments. It turned out that the intensity perception of odorants weights airflow sensation, which reflected a synergy between the olfactory and the trigeminal system.

(2) Study II probed the relationship between arousal and intensity in olfactory perception. With two odorants matched in intensity and valence, we compared the physiological arousal state mainly through resting electroencephalography (EEG) and the attentional blink task between odor conditions. The results showed that the more aroused odor induced a more aroused resting neural oscillation state and better performance in the attentional blink task.

(3) Study III further explored the neural mechanism beneath different T2 performance in the attentional blink task induced by odor arousal. EEG was applied to record the real time neural response both before and during the presentation of stimuli in different smell conditions. We found that the more aroused odor promoted task performance by increasing anticipatory preparation and attentional allocation to the targets, as well as preventing the brain from the inhibited alpha involvement.