Effects of transcutaneous auricular vagus nerve stimulation on reversal learning, tonic pupil size, salivary alpha‐amylase, and cortisol.

Saved in:

Bibliographic Details
Title:	Effects of transcutaneous auricular vagus nerve stimulation on reversal learning, tonic pupil size, salivary alpha‐amylase, and cortisol.
Authors:	D'Agostini, Martina (AUTHOR), Burger, Andreas M. (AUTHOR), Franssen, Mathijs (AUTHOR), Claes, Nathalie (AUTHOR), Weymar, Mathias (AUTHOR), von Leupoldt, Andreas (AUTHOR), Van Diest, Ilse (AUTHOR)
Source:	Psychophysiology. Oct2021, Vol. 58 Issue 10, p1-20. 20p. 1 Color Photograph, 2 Diagrams, 3 Charts, 2 Graphs.
Subjects:	Hydrocortisone, Alpha-amylase, Saliva, Ear, Learning, Vagus nerve stimulation
Abstract:	This study investigated whether transcutaneous auricular vagus nerve stimulation (taVNS) enhances reversal learning and augments noradrenergic biomarkers (i.e., pupil size, cortisol, and salivary alpha‐amylase [sAA]). We also explored the effect of taVNS on respiratory rate and cardiac vagal activity (CVA). Seventy‐one participants received stimulation of either the cymba concha (taVNS) or the earlobe (sham) of the left ear. After learning a series of cue‐outcome associations, the stimulation was applied before and throughout a reversal phase in which cue‐outcome associations were changed for some (reversal), but not for other (distractor) cues. Tonic pupil size, salivary cortisol, sAA, respiratory rate, and CVA were assessed at different time points. Contrary to our hypothesis, taVNS was not associated with an overall improvement in performance on the reversal task. Compared to sham, the taVNS group performed worse for distractor than reversal cues. taVNS did not increase tonic pupil size and sAA. Only post hoc analyses indicated that the cortisol decline was steeper in the sham compared to the taVNS group. Exploratory analyses showed that taVNS decreased respiratory rate but did not affect CVA. The weak and unexpected effects found in this study might relate to the lack of parameters optimization for taVNS and invite to further investigate the effect of taVNS on cortisol and respiratory rate. Contrary to our hypotheses, we did not observe enhancing effects of transcutaneous auricular vagus nerve stimulation (taVNS) on reversal learning and noradrenergic markers. Our findings question whether a commonly used parameter‐setup of taVNS can activate the vagus nerve and modulate noradrenergic activity. These results add to a growing body of zero findings and call for more basic taVNS research regarding optimal stimulation parameters and locations. [ABSTRACT FROM AUTHOR]
	Copyright of Psychophysiology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database:	Psychology and Behavioral Sciences Collection

Description
Abstract:	This study investigated whether transcutaneous auricular vagus nerve stimulation (taVNS) enhances reversal learning and augments noradrenergic biomarkers (i.e., pupil size, cortisol, and salivary alpha‐amylase [sAA]). We also explored the effect of taVNS on respiratory rate and cardiac vagal activity (CVA). Seventy‐one participants received stimulation of either the cymba concha (taVNS) or the earlobe (sham) of the left ear. After learning a series of cue‐outcome associations, the stimulation was applied before and throughout a reversal phase in which cue‐outcome associations were changed for some (reversal), but not for other (distractor) cues. Tonic pupil size, salivary cortisol, sAA, respiratory rate, and CVA were assessed at different time points. Contrary to our hypothesis, taVNS was not associated with an overall improvement in performance on the reversal task. Compared to sham, the taVNS group performed worse for distractor than reversal cues. taVNS did not increase tonic pupil size and sAA. Only post hoc analyses indicated that the cortisol decline was steeper in the sham compared to the taVNS group. Exploratory analyses showed that taVNS decreased respiratory rate but did not affect CVA. The weak and unexpected effects found in this study might relate to the lack of parameters optimization for taVNS and invite to further investigate the effect of taVNS on cortisol and respiratory rate. Contrary to our hypotheses, we did not observe enhancing effects of transcutaneous auricular vagus nerve stimulation (taVNS) on reversal learning and noradrenergic markers. Our findings question whether a commonly used parameter‐setup of taVNS can activate the vagus nerve and modulate noradrenergic activity. These results add to a growing body of zero findings and call for more basic taVNS research regarding optimal stimulation parameters and locations. [ABSTRACT FROM AUTHOR]
ISSN:	00485772
DOI:	10.1111/psyp.13885