Ultrasound transcutaneous auricular vagus nerve stimulation enhances semantic processing
Youbin Kang, Marcus Kaiser, JeYoung Jung
2026 · 10.64898/2026.02.20.707135
Abstract
Efficient access to conceptual knowledge is central to everyday cognition, yet the effects of non-invasive neuromodulation on semantic retrieval remain insufficiently characterised. Transcutaneous auricular vagus nerve stimulation (taVNS) offers a mechanistically distinct route to modulate distributed cognitive systems via ascending vagal afferent pathways, but its effects on semantic processing has not been explored. Here, we tested whether ultrasound-based taVNS delivered to the right cymba conchae can acutely enhance semantic retrieval efficiency in healthy adults. Twenty-seven participants completed a single blind, sham-controlled study comprising two counterbalanced sessions (active vs. sham) in a within-subject design, separated by at least five days. In each session, participants performed a semantic association task and a number-judgement control task before and immediately after 30 minutes of stimulation. Active taVNS produced selective post-stimulation improvements in semantic retrieval performance relative to sham and baseline, while performance on the control task remained unchanged. Adverse effects were minimal and did not differ between active and sham conditions. These findings provide causal evidence that ultrasound-based taVNS can acutely improve the efficiency of semantic processing, expanding the cognitive profile of taVNS beyond predominantly episodic and emotional memory domains and supporting its feasibility as a scalable approach for memory enhancement.
Abstract via europepmc.
Exposures
Exposure 1: Active U-taVNS (ultrasound taVNS, right cymba conchae)
Target: vagus nerve — “auricular branch of the vagus nerve (right cymba conchae)”
Device: other named manufacturer · NeurGear Inc. · ZenBud ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 5,300 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 12.1951 ms (not stated by the paper) | ⚑ |
| Pulse repetition frequency (Hz) | 41 | ✓✓✓ |
| Duty cycle (%) | 50 | ✓✓✓ |
| Sonication duration (s) | 1,800 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Pressure, domain unspecified (kPa) | 1,030 | ✓✓✓⚑ |
| Isppa, domain unspecified (W/cm²) | 0.081 | ✓✓✓ |
Participants received 30 minutes of taVNS (active or sham) after the pre-stimulation session; the semantic association task and a number-judgement control task were repeated immediately after stimulation (post-stimulation session).
Consistency checks: intensity pressure inconsistent unspecified domain.
Flags from extraction
sham_type— The paper states there was an 'active stimulation session and a sham session' but does not describe the sham device/mechanism (unlike the companion Kang emotional-bias paper), so sham mechanism is unspecified.exposures[0].unspecified_domain.pressure_kpa— Sentence gives 'an average pressure amplitude of 1.03 MPa' alongside a separately labelled 'peak mechanical output of 0.081 W/cm2'; domain (free-field vs in-situ) is not stated for either value.exposures[0].timing.pulse_duration_ms— Only duty cycle (50%) and PRF (41 Hz) are stated; per-pulse duration is not explicitly reported and was not computed from DC/PRF.readout_timing— Tasks were performed before and immediately after the 30-minute stimulation period; no assessment during stimulation is described, so timing is classified as offline.