Odour imagery, the ability to experience smell when an appropriate stimulus is absent, has widely been documented as being particularly difficult. However, previous studies have shown the beneficial effect of visual cues ( pictures or words) to facilitate performance in numerous tasks of olfactory nature. Therefore, the use of visual cues to evoke odours seems relevant. In this study, our interest is directed towards non-figurative coloured arrangements, which result from a patented technology and aim at chromatically representing any smell from its chemical composition and sensory description. The aim of this study was to characterise the neural mechanisms of odour imagery facilitated by these non-figurative coloured arrangements. Using functional magnetic resonance imaging, we recorded and compared hemodynamic responses during odour imagery facilitated by non-figurative coloured arrangements and pictures. Our findings reveal that the use of non-figurative coloured arrangements during odour imagery solicits olfactory and non-olfactory brain regions (orbitofrontal cortex, insula, hippocampus, thalamus, dorsolateral prefrontal cortex and supplementary motor area), which are mainly involved in olfactory processing and multimodal integration. Moreover, very similar cortical activity was found between the use of non-figurative coloured arrangements and pictures during odour imagery, with increased activity in the supplementary motor area during the use of coloured arrangements only. Overall, non-figurative coloured arrangements could become a robust tool to visually evoke odours without requiring prior familiarity with the depicted odour. Future studies should use psychometric measures to determine the relationships between brain activation, odour imagery ability and vividness of the generated odour images.

中文翻译：

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非象征性视觉线索诱发气味意象的神经机制

气味意象，即在缺乏适当刺激时体验气味的能力，被广泛认为是特别困难的。然而，之前的研究已经表明视觉线索（图片或文字）对于促进许多嗅觉性质的任务的执行具有有益的作用。因此，使用视觉线索来唤起气味似乎是相关的。在这项研究中，我们的兴趣集中在非象征性的彩色排列上，这种排列是由一项专利技术产生的，旨在从化学成分和感官描述中通过色彩来表现任何气味。这项研究的目的是表征这些非象征性的颜色排列所促进的气味意象的神经机制。使用功能性磁共振成像，我们记录并比较了由非象征性彩色排列和图片促进的气味图像期间的血流动力学反应。我们的研究结果表明，在气味意象中使用非比喻性的颜色排列会刺激嗅觉和非嗅觉大脑区域（眶额皮质、岛叶、海马、丘脑、背外侧前额皮质和辅助运动区），这些区域主要参与嗅觉处理和嗅觉处理。多式联运一体化。此外，在气味意象中使用非象征性的彩色排列和图片之间发现了非常相似的皮层活动，仅在使用彩色排列时辅助运动区的活动增加。总体而言，非象征性的彩色排列可以成为一种在视觉上唤起气味的强大工具，而无需事先熟悉所描绘的气味。未来的研究应该使用心理测量来确定大脑激活、气味想象能力和所生成的气味图像的生动性之间的关系。