Effects of transcutaneous auricular vagus nerve stimulation on associative memory, event-related potential P300 and P600: a single-blind pilot experiment on healthy adults.

Abstract

Transcutaneous auricular vagus nerve stimulation (taVNS) is attracting attention as a new neuromodulation technique to improve cognitive function. The effects of this neuromodulation technique on associative memory and its mechanisms have not been fully investigated. This crossover, single-blind, active-versus-sham design experiment examined the effects of taVNS on associative memory performance and the event-related potential P300 or P600. The experiment consisted of an associative memory task with encoding and retrieval as a set, performed three timepoints with a 10 min rest period, on 14 healthy adults. Participants received taVNS or sham during the 10 min rest between the time 1 and time 2. Event-related potentials were measured at each time of the associative memory task. The washout for this experiment was set at one week. We analyzed the effects of taVNS by means of a general linear mixed model with performance on three associative memory tasks and peak amplitude of event-related potential P300 or P600 as dependent variables. The results presented an interaction effect of taVNS and timepoints on associative memory performance. Conversely, no effects on the event-related potentials P300 and P600 were observed. This noninvasive neuromodulation technique holds potential for applications in rehabilitation for cognitive function. Further research is needed to generalize the results of this pilot study. Registration: University Hospital Medical Information Network Center (No. UMIN000055911), date: January 24, 2024 "retrospectively registered".