Transcutaneous vagus nerve stimulation during semantic verbal fluency tasks: a high-density diffuse optical tomography study.
4 affiliations
- 1Department of Neuroscience, Sheffield Institute of Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom.
- 2School of Psychology, University of Sheffield, Sheffield, United Kingdom.
- 3Department of Electrical Engineering, University of Cambridge, Cambridge, United Kingdom.
- 4Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
Abstract
Introduction
Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising adjunct for post-stroke language recovery. There are no established biomarkers for the neuromodulatory effects of taVNS. High-density diffuse optical tomography (HD-DOT) offers a non-invasive marker of task-related cortical activation. We explore HD-DOT in determining the effects of taVNS during a semantic verbal fluency task (VFT).Methods
Twenty-four healthy adult participants performed a semantic VFT in a block design, whilst HD-DOT was recorded across the bilateral prefrontal cortex. Participants received sham (earlobe) taVNS followed by active (tragus) taVNS. Statistical analysis was performed at a group level within condition (task-baseline) and between conditions (active taVNS vs. sham taVNS) using node-level and parcellation approaches.Results
Twenty-one participants (87.5%) met the signal quality threshold. At the uncorrected level, significant increases in task-related activity were seen in the triangular part of the left inferior frontal gyrus, during both the active and sham taVNS. Correcting for multiple comparisons, significant increases were seen in the left lateral orbitofrontal cortex during sham stimulation. No significant differences in oxygenated haemoglobin concentration increase were seen between active and sham taVNS.Discussion
Simultaneous recording of brain activity to taVNS during a semantic VFT was feasible and well tolerated. Task-related activation was seen in brain regions associated with language production and decision-making. Through this exploratory work, healthy adults do not demonstrate any significant enhancement of frontal cortical activation from taVNS. Future studies should combine whole-brain HD-DOT and taVNS in clinical cohorts.
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BibTeX
@article{illingworth2026transcutaneous,
title = {{Transcutaneous vagus nerve stimulation during semantic verbal fluency tasks: a high-density diffuse optical tomography study.}},
author = {Caitlin H Illingworth and Sheharyar S Baig and Jasmine Swalwell and Michal Holowacz and Samantha L Dorney and Sabrina Di Lonardo Burr and Emilia Butters and Daniel Blackburn and Ali Ali and Arshad Majid and Li Su},
journal = {Frontiers in human neuroscience},
year = {2026},
month = oct,
doi = {10.3389/fnhum.2026.1964706},
url = {https://europepmc.org/article/MED/42898386},
note = {CC BY},
}
RIS
TY - JOUR
TI - Transcutaneous vagus nerve stimulation during semantic verbal fluency tasks: a high-density diffuse optical tomography study.
AU - Caitlin H Illingworth
AU - Sheharyar S Baig
AU - Jasmine Swalwell
AU - Michal Holowacz
AU - Samantha L Dorney
AU - Sabrina Di Lonardo Burr
AU - Emilia Butters
AU - Daniel Blackburn
AU - Ali Ali
AU - Arshad Majid
AU - Li Su
PY - 2026
DA - 2026/10/05
JO - Frontiers in human neuroscience
DO - 10.3389/fnhum.2026.1964706
UR - https://europepmc.org/article/MED/42898386
AB - Introduction Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising adjunct for post-stroke language recovery. There are no established biomarkers for the neuromodulatory effects of taVNS. High-density diffuse optical tomography (HD-DOT) offers a non-invasive marker of task-related cortical activation. We explore HD-DOT in determining the effects of taVNS during a semantic verbal fluency task (VFT).Methods Twenty-four healthy adult participants performed a semantic VFT in a block design, whilst HD-DOT was recorded across the bilateral prefrontal cortex. Participants received sham (earlobe) taVNS followed by active (tragus) taVNS. Statistical analysis was performed at a group level within condition (task-baseline) and between conditions (active taVNS vs. sham taVNS) using node-level and parcellation approaches.Results Twenty-one participants (87.5%) met the signal quality threshold. At the uncorrected level, significant increases in task-related activity were seen in the triangular part of the left inferior frontal gyrus, during both the active and sham taVNS. Correcting for multiple comparisons, significant increases were seen in the left lateral orbitofrontal cortex during sham stimulation. No significant differences in oxygenated haemoglobin concentration increase were seen between active and sham taVNS.Discussion Simultaneous recording of brain activity to taVNS during a semantic VFT was feasible and well tolerated. Task-related activation was seen in brain regions associated with language production and decision-making. Through this exploratory work, healthy adults do not demonstrate any significant enhancement of frontal cortical activation from taVNS. Future studies should combine whole-brain HD-DOT and taVNS in clinical cohorts.
SN - 1662-5161
ER -