title: A unique memory process modulated by emotion underpins successful odor recognition and episodic retrieval in humans.
abstract: We behaviorally explore the link between olfaction, emotion and memory by testing the hypothesis that the emotion carried by odors facilitates the memory of specific unique events. To investigate this idea, we used a novel behavioral approach inspired by a paradigm developed by our team to study episodic memory in a controlled and as ecological as possible way in humans. The participants freely explored three unique and rich laboratory episodes; each episode consisted of three unfamiliar odors (What) positioned at three specific locations (Where) within a visual context (Which context). During the retrieval test, which occurred 24-72 h after the encoding, odors were used to trigger the retrieval of the complex episodes. The participants were proficient in recognizing the target odors among distractors and retrieving the visuospatial context in which they were encountered. The episodic nature of the task generated high and stable memory performances, which were accompanied by faster responses and slower and deeper breathing. Successful odor recognition and episodic memory were not related to differences in odor investigation at encoding. However, memory performances were influenced by the emotional content of the odors, regardless of odor valence, with both pleasant and unpleasant odors generating higher recognition and episodic retrieval than neutral odors. Finally, the present study also suggested that when the binding between the odors and the spatio-contextual features of the episode was successful, the odor recognition and the episodic retrieval collapsed into a unique memory process that began as soon as the participants smelled the odors.
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Saive
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Royet
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Ravel
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Thévenet
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Garcia
authors.affiliation: Lyon Neuroscience Research Center, CNRS UMR 5292 - INSERM U1028 - University Lyon1 Lyon, France.
authors.forename: Jane
authors.initials: J
authors.lastname: Plailly
keywords: breathing; emotion; encoding; episodic memory; human; olfaction; recognition memory; visuospatial context