Mental activity in sleep often involves visual and auditory content. Chemosensory (olfactory and gustatory) experiences are less common and underexplored. The aim of the study was to identify olfaction-related factors that may affect the occurrence of chemosensory dream content. Specifically, we investigated the effects of all-night exposure to an ambient odour, participants’ appraisal of their current olfactory environment, their general propensity to notice odours and act on them (i.e., odour awareness), and their olfactory acuity. Sixty pre-screened healthy young adults underwent olfactory assessment, completed a measure of odour awareness, and spent three nights in weekly intervals in a sleep laboratory. The purpose of the first visit was to adapt to the experimental setting. On the second visit, half of them were exposed to the smell of vanillin or thioglycolic acid and the other half to an odourless control condition. On the third visit, they received control or stimulation in a balanced order. On each visit, data were collected twice: once from the first rapid eye movement (REM) stage that occurred after 3 a.m., and then shortly before getting up, usually from a non-REM stage. Participants were asked to report the presence of sensory dream content and to assess their current olfactory environment. Neither exposure, nor participants’ assessments of the ambient odour, or olfactory acuity affected reports of chemosensory dream content but they were more frequent in individuals with greater odour awareness. This finding may have implications for treatment when such experiences become unwanted or bothersome.

中文翻译：

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睡眠实验室中影响化学感觉梦内容的嗅觉相关因素

睡眠中的心理活动通常涉及视觉和听觉内容。化学感觉（嗅觉和味觉）体验不太常见且尚未得到充分探索。该研究的目的是确定可能影响化学感觉梦内容发生的嗅觉相关因素。具体来说，我们调查了整夜暴露在环境气味中的影响、参与者对当前嗅觉环境的评估、他们注意到气味并采取行动的一般倾向（即气味意识）以及他们的嗅觉敏锐度。六十名经过预先筛选的健康年轻人接受了嗅觉评估，完成了气味意识测量，并每周在睡眠实验室呆了三个晚上。第一次来的目的是为了适应实验环境。在第二次访问时，其中一半暴露在香草醛或巯基乙酸的气味中，另一半暴露在无气味的对照条件下。在第三次访问时，他们以平衡的顺序接受控制或刺激。每次访问时，数据都会收集两次：一次是在凌晨 3 点后发生的第一个快速眼动 (REM) 阶段，然后是起床前不久，通常是非快速眼动阶段。参与者被要求报告感官梦内容的存在并评估他们当前的嗅觉环境。暴露、参与者对环境气味或嗅觉敏锐度的评估都不会影响化学感应梦内容的报告，但在气味意识较强的个体中，这种情况更为常见。当此类经历变得不受欢迎或令人烦恼时，这一发现可能会对治疗产生影响。