Strengthened Hippocampal Circuits Underlie Enhanced Retrieval of Extinguished Fear Memories Following Mindfulness Training

Gunes Sevinc,Britta K Hölzel,Jonathan Greenberg,Tim Gard,Vincent Brunsch,Javeria A Hashmi,Mark Vangel,Scott P Orr,Mohammed R Milad,Sara W Lazar

doi:10.1016/j.biopsych.2019.05.017

Abstract

BackgroundThe role of hippocampus in context-dependent recall of extinction is well recognized. However, little is known about how intervention-induced changes in hippocampal networks relate to improvements in extinction learning. In this study, we hypothesized that mindfulness training creates an optimal exposure condition by heightening attention and awareness of present moment sensory experience, leading to enhanced extinction learning, improved emotion regulation, and reduced anxiety symptoms. MethodsWe tested this hypothesis in a randomized controlled longitudinal study design using a 2-day fear conditioning and extinction protocol. The mindfulness training group included 42 participants (28 women) and the control group included 25 participants (15 women). ResultsWe show that mindfulness training is associated with differential engagement of the right supramarginal gyrus as well as hippocampal-cortical reorganization. We also report enhanced hippocampal connectivity to the primary sensory cortex during retrieval of extinguished stimuli following mindfulness training. ConclusionsThese findings suggest hippocampal-dependent changes in contextual retrieval as one plausible neural mechanism through which mindfulness-based interventions enhance fear extinction and foster stress resilience.

Highlights

The role of hippocampus in context-dependent recall of extinction is well recognized
Mindfulness Training Leads to Improvements in Anxiety and Emotion Regulation
Relying on the role of the hippocampus in retrieval of contextual information to signal safety [5], we postulated that mindfulness training would promote changes in the hippocampus and thereby enhance extinction memory retrieval

Summary

Introduction

The role of hippocampus in context-dependent recall of extinction is well recognized. Little is known about how intervention-induced changes in hippocampal networks relate to improvements in extinction learning. We hypothesized that mindfulness training creates an optimal exposure condition by heightening attention and awareness of present moment sensory experience, leading to enhanced extinction learning, improved emotion regulation, and reduced anxiety symptoms. METHODS: We tested this hypothesis in a randomized controlled longitudinal study design using a 2-day fear conditioning and extinction protocol. We report enhanced hippocampal connectivity to the primary sensory cortex during retrieval of extinguished stimuli following mindfulness training. CONCLUSIONS: These findings suggest hippocampal-dependent changes in contextual retrieval as one plausible neural mechanism through which mindfulness-based interventions enhance fear extinction and foster stress resilience

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Conclusion