Differential effects of immediate vs. delayed extinction training and the variation of the time interval between extinction training and test on the return of fear: neural and peripheral-physiological correlates

• Applicant: Professor Dr. Tim Klucken
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 396254081

Conditioning and extinction processes are considered important models for the development, maintenance, and treatment of psychiatric disorders. While fear conditioning has previously been examined in considerable detail, the investigation of extinction processes has only gained increasing attention over the last years. An important factor in the context of relapses is the return of fear during a retention test after initially successful extinction training; a phenomenon considered to have important practical implications for clinical relapses. Understanding which factors contribute to such long-term stability or instability of fear extinction processes is therefore an important research aim for clinical psychology.One often neglected factor in this context is the exact timing of extinction training. Extinction training is usually either conducted immediately after fear acquisition or with a 24h delay. Animal research as well as current memory models postulate that the exact timing (immediate vs. delayed) of extinction training may have an important impact on the magnitude of the return of fear effect. In addition, previous results showed that the time interval between extinction training and the testing of extinction retention might also impact the return of fear in interaction with the used extinction training. For instance, robust extinction results could be observed when conducting a delayed extinction training and a short time interval to the retention test.The aim of this DFG-project is to investigate the similarities and differences between immediate and delayed extinction training and the impact on the return of fear. In addition, the effect of the time interval between extinction training and test should be also investigated as well as the time course within each extinction session and the underlying neural processes. Finally, it is planned to identify potential factors that are related to robust extinction success. A differential extinction paradigm will be conducted to compare extinction processes and the return of fear between four groups. In two groups, extinction learning will be conducted directly after fear acquisition, while a 24h-delayed extinction learning paradigm will be performed in the other two groups. In addition, the time interval between extinction training and retention test will be varied between the groups (1 day vs. 7 days) to compare the return of fear of the groups.The submitted project will provide valuable and currently still lacking information, bridging the gap between animal research and the corresponding neurobiological processes in humans.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Rudolf Maria Stark