TY  - JOUR
AU  - Keute, Marius
AU  - Demirezen, Mustafa
AU  - Graf, Alina
AU  - Müller, Notger
AU  - Zaehle, Tino
TI  - No modulation of pupil size and event-related pupil response by transcutaneous auricular vagus nerve stimulation (taVNS).
JO  - Scientific reports
VL  - 9
IS  - 1
SN  - 2045-2322
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - DZNE-2020-07190
SP  - 11452
PY  - 2019
AB  - Transcutaneous auricular vagus nerve stimulation (taVNS) bears therapeutic potential for a wide range of medical conditions. However, previous studies have found substantial interindividual variability in responsiveness to taVNS, and no reliable predictive biomarker for stimulation success has been developed so far. In this study, we investigate pupil size and event-related pupil response as candidate biomarkers. Both measures have a direct physiological link to the activity of the locus coeruleus (LC), a brainstem structure and the main source of norepinephrine in the brain. LC activation is considered one of the key mechanisms of action of taVNS, therefore, we expected a clear increase of the pupillary measures under taVNS compared to sham (placebo) stimulation, such that it could serve as a prospective predictor for individual clinical and physiological taVNS effects in future studies. We studied resting pupil size and pupillary responses to target stimuli in an auditory oddball task in 33 healthy young volunteers. We observed stronger pupil responses to target than to standard stimuli. However, and contrary to our hypothesis, neither pupil size nor the event-related pupil response nor behavioral performance were modulated by taVNS. We discuss potential explanations for this negative finding and its implications for future clinical investigation and development of taVNS.
KW  - Adult
KW  - Depression: therapy
KW  - Ear Auricle: innervation
KW  - Electrodes
KW  - Epilepsy: therapy
KW  - Female
KW  - Healthy Volunteers
KW  - Humans
KW  - Locus Coeruleus: physiology
KW  - Male
KW  - Pupil: physiology
KW  - Skin: innervation
KW  - Transcutaneous Electric Nerve Stimulation: instrumentation
KW  - Transcutaneous Electric Nerve Stimulation: methods
KW  - Vagus Nerve: physiology
KW  - Vagus Nerve Stimulation: instrumentation
KW  - Vagus Nerve Stimulation: methods
KW  - Young Adult
LB  - PUB:(DE-HGF)16
C6  - pmid:31391505
C2  - pmc:PMC6685960
DO  - DOI:10.1038/s41598-019-47961-4
UR  - https://pub.dzne.de/record/140868
ER  -