Access to emotional memories: Evidence for a vagal route to boost memory retrieval using non-invasive taVNS

Remembering emotionally significant events is critical for the organisms' behavior and survival. While the mechanisms underlying formation of such memories are well understood and closely linked to the vagus nerve and the brain's arousal system, less is known about its contribution to memory retrieval. The current study tested whether non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) applied during a long-term recognition memory task influenced retrieval of unpleasant and neutral scenes that have been incidentally encoded one week earlier. Results showed that taVNS, compared to a sham condition, selectively enhanced the recollection of unpleasant images. Despite a modest effect size (d = 0.33), these findings provide first human evidence for a direct link of the vagus nerve in emotional memory retrieval, thus extending current theoretical models of emotional memory retrieval and opening a new pathway for memory modulation and non-invasive therapeutic interventions.