Does the heart forget? Modulation of cardiac activity induced by inhibitory control over emotional memories

The subjective construction surrounding the perception of negative experience is partly build upon bodily afferent information, comprising heart, gut or respiratory signals. While this bottom-up influence has been extensively described, the opposite pathway, the putative influence of cognitive processes over autonomic response, is still debatable. However, emotion regulation and the ability to control maladjusted physiological response associated with thoughts and memories is a recurrent concern for most psychiatric disorders and mental health as a whole. Memory suppression (i.e. exerting inhibitory control toward unwanted memories) has been proposed as a possible solution to perform such regulation. However, this method also holds debates as it could putatively worsen distressing reactions when unsuccessful, or simply be ineffective on the physiological roots of emotions. Here, we tested the hypothesis that memory suppression can influence the physiological markers of emotions in two studies using the "Think/No-Think" paradigm. We measured in healthy participants the aftereffect of suppressing negative memories on their cardiac reaction toward the excluded memories. Results of Study 1 revealed that an efficient control of memories was associated with a long-term inhibition of the cardiac deceleration normally induced by disgusting stimuli. Study 2 replicated this finding and critically showed that it was linked to the decrease of the 5-9 Hz frequency band, a prominent electrophysiological markers of memory suppression. These results support the notion that cognitive control over unwanted emotional memories can influence in parallel autonomic processes to achieve emotional regulation, and open new avenues for possible interventions focused on training this suppression mechanism to reduce the impact of distressing intrusive memories on mental health.