Procedure

A venous blood sample was taken in the morning (between 9 and 10 A.M.). The same day, between noon and 2 P.M., subjects were exposed to an odor-triggered retrieval session, and the subjects were video monitored during the procedure (with their consent). The instruction was to recall and enunciate an episode from their lives that the current odor brings to memory. After each event retrieved, subjects completed the questionnaire measuring valance, vividness, and personal relevance. The procedure took ∼30 min. Six to 8 h after this session, all subjects have been scanned using resting-state functional connectivity MRI procedure.

After the Pre-training session, each subject from the experimental group underwent an autobiographical reminder training for 1 h, two times per week, for four weeks. The experimental group was stimulated to recall autobiographic memories using 15 odors. The participant took each container in his/her hand and smelled its contents through the holes in the lid. He/she waited for a maximum of 20 s to see whether a memory triggered by that smell appears. If a memory appeared, she/he described it in as much detail as possible. If not, he/she moved on to the next container. Subjects were encouraged to detail the memories as much as possible, insisting on the description of sensory, social, and emotional details. After the Pre-training session, each subject from the control group watched two short movies for 45 min, two times per week, for four weeks.

After four weeks, all subjects were exposed to the same procedure used in the Pre-training session. A venous blood sample was taken in the morning (between 9 and 10 A.M.). The same day, between noon and 2 P.M., subjects were exposed to an odor-triggered retrieval session and the subjects were video monitored during the procedure (with their consent). The instruction was to recall and enunciate an episode from their lives that the current odor brings to memory. After each event retrieved, subjects completed the questionnaire measuring valance, vividness, and personal relevance. Additionally, subjects completed the scales for spontaneous and voluntary memory retrieval in daily life, outside the lab. Six to 8 h after this session, all subjects have been scanned using resting-state functional connectivity MRI procedure.