Stimulate to Remember? The Effects of Short Burst of Transcutaneous Vagus Nerve Stimulation (taVNS) on Memory Performance and Pupil Dilation

The decline in noradrenergic (NE) locus coeruleus (LC) function in aging is thought to be implicated in episodic memory decline. Transcutaneous auricular vagus nerve stimulation (taVNS), which supports LC function, might serve to preserve or improve memory function in aging. However, taVNS effects are generally very heterogeneous, and it is currently unclear whether taVNS has an effect on memory. In this study, an emotional memory task with negative events involving the LC-NE system was combined with the short burst of event-related taVNS (3 s) in younger adults (N = 24). The aim was to investigate taVNS-induced changes in pupil dilation during encoding and possible taVNS-induced improvements in (emotional) memory performance for early and delayed (24 h) recognition. Negative events were associated with increased pupil dilation and better memory performance. Additionally, real as compared to sham or no stimulation selectively increased memory for negative events. Short bursts of stimulation, whether real or sham, led to an increase in pupil dilation and an improvement in memory performance over time, likely due to the attention-inducing sensory modulation of electrical stimulation.