title: Effects of memory age and interval of fear extinction sessions on contextual fear extinction.
abstract: Fear extinction is a major task in our understanding of the biological mechanisms of exposure therapy, one of the most used treatments for stress-related disorders. It was recently reported that an extinction of 5 consecutive days prevents spontaneous recovery of fear memory. Memory age and the timing of fear extinction influence the effect of fear extinction. In this study, we used contextual fear extinction in adult male mice to examine whether memory age influences an extinction of 5 consecutive days and whether consecutiveness is necessary to prevent spontaneous recovery. Our results showed that, although fear memory was not affected by the passage of time, the old fear memory (28 days after fear conditioning) was more sensitive to fear extinction than the young fear memory (7 days after fear conditioning). Additionally, we demonstrated that consecutiveness of extinction sessions is not necessary to prevent spontaneous recovery. Instead, fear extinction sessions at spaced intervals were found to be more effective than consecutive extinction sessions for young fear memory. Our results suggest that taking memory age and the interval of fear extinction sessions into consideration would help to optimize exposure therapy.
authors.affiliation: Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan. Electronic address: matsutsuma@gmail.com.
authors.forename: Shingo
authors.initials: S
authors.lastname: Matsuda
authors.affiliation: Department of Cognitive Behavioral Physiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan; Research Center for Child Mental Development, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Matsuzawa
authors.affiliation: Department of Cognitive Behavioral Physiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ishii
authors.affiliation: Department of Cognitive Behavioral Physiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan.
authors.forename: Haruna
authors.initials: H
authors.lastname: Tomizawa
authors.affiliation: Department of Cognitive Behavioral Physiology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan; Research Center for Child Mental Development, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D003214:Conditioning, Classical; D005108:Extinction, Psychological; D005239:Fear / Q000523:psychology*; D008297:Male; D008568:Memory; D011939:Mental Recall; D051379:Mice; D008810:Mice, Inbred C57BL; D013997:Time Factors
keywords: Fear conditioning; Fear extinction; Fear incubation; Memory age; Spontaneous recovery