MEntal Representation of ODors: from physical features to perceptual processing

大约在世纪之交，认为文明人可以没有嗅觉的想法变得过时了：这种迄今被认为对认知来说是多余的、口齿不清的感觉，本身就成了研究的焦点。它被诺贝尔奖认定为科学对象；此外，社会更加享乐主义，因此更关注气味的情感影响。气味既是快乐的源泉，也是社会纽带的源泉；它们影响我们的性行为以及与他人的关系，特别是与我们孩子的关系。它们有助于我们的情绪平衡：嗅觉损伤破坏了这种平衡。认知心理学中的一个重要问题是了解人脑如何代表气味物体。视觉对象的表示被更好地理解；我们知道视觉刺激的物理和感知属性是以分布式和分级的方式表示的，但仍然不清楚气味分子的化学性质和气味的感知方面是如何沿着人类嗅觉通路表示的。在本项目中，我们假设气味的多维表征是一种神经机制的结果，该机制处理嗅觉系统不同阶段的化学信息和感知信息的相似性。德国团队(德累斯顿技术大学的Hummel实验室)和法国团队(里昂大学和CNRS的本萨菲实验室)的努力结合在一起，将进行三组实验，包括三项任务。在第一个任务中，我们将在法国和德国在大样本参与者中进行一系列广泛的心理物理实验，以确定一组化学和感知特性不同的气味。这个气味数据库将能够选择在德累斯顿和里昂执行的两个独立实验任务中使用的气味。在第二个实验任务中，将在新手(非专家)和嗅觉专家(香水师，他们对气味有更高的辨别能力)中测试中央嗅觉区(梨状皮质、杏仁核和眶前皮质)在提取气味和气味之间的化学和感知相似性方面的作用。在第三个任务中，将探索人类嗅球(气味信息的第一个传递)在提取不同气味之间的化学相似性方面所起的作用。在第二个目标中，我们将根据该项目的原始发现，在普通公众和高等教育中促进关于嗅觉的科学文化和交流。因此，本项目旨在以最初的目标在国际竞争中定位自己。它结合了人类嗅觉和认知心理学的专业知识。它的目的是更好地理解气味的心理表征，从基本的角度破译气味的神经组织，并从教育的角度提供嗅觉心理学领域的原创课程。

Around the turn of the century the idea that civilized human beings might do without olfaction became outdated: this inarticulate sense, hitherto considered superfluous to cognition, became a focus of study in its own right. It was acknowledged as an object of science by Nobel prizes; in addition, society ecame more hedonistic, and hence more attentive to the emotional effects of odors. Odors are sources of both pleasure and social bonding; they influence our sexuality and relations with others in general and with our children in particular. They contribute to our emotional balance: olfactory damage impairs this equilibrium. An important issue in cognitive psychology is to understand how the human brain represents odor objects. Representation of visual objects is far better understood; we know that physical and perceptual attributes of visual stimuli are represented in a distributed and hierarchical manner, but it is still unclear how chemical properties of odorant molecules and perceptual aspects of odors are represented along the human olfactory pathway. In the present project, we hypothesize that the multidimensional representation of odors is the result of a neural mechanism that processes similarities of chemical information and perceptual information at various stages of the olfactory system. Three sets of experiments embedded in 3 Tasks combining the efforts of a German team (Hummel lab at the Technical Unversity of Dresden) and a French team (Bensafi lab at the University of Lyon and CNRS) will be conducted. In the first Task, we shall realize a series of extensive psychophysical experiments in both France and Germany in a large sample of participants to define a set of odorants varying in chemical and perceptual properties. This odor database will enable selection of odors used in the two following, independent experimental tasks performed in Dresden and Lyon. In the second experimental Task, the role of central olfactory areas (piriform cortex, amygdala and orbitofrontal cortex) in extracting both chemical and perceptual similarities across odorants and odors will be tested in novices (non-experts) and experts in olfaction (perfumers, who have higher discrimination abilities about odors). In the third Task, the role of the human olfactory bulb (the first relay of odor information) in extracting chemical similarities across odorants will be explored. In a second aim, we will promote scientific culture and communication on olfaction in the general public and in higher education based on the original findings from the project. Thus, the present project aims to position itself in international competition with original objectives. It combines expertise in human olfaction and cognitive psychology. It aims to better understand mental representation of smells, in a fundamental perspective for deciphering their neural organization, and in an educational perspective for providing original courses i the field of psychology of smells.