ID 215 – Transcutaneous trigeminal nerve stimulation induces a long-term depression-like plasticity of the human blink reflex

Abstract

Objective To test the after-effects of 20-min, cyclic transcutaneous trigeminal nerve stimulation (TNS) on the excitability of the blink reflex (BR). Methods The areas of the R1 and R2 components of the BR were measured in 20 healthy subjects before and at 0–5, 15, 20, 30 and 45 min after TNS (asymmetric biphasic square wave pulses: duration 250 μ s, intensity 1–20 mA, frequency 120 Hz, alternating 30s ON, 30s OFF for 20 min) delivered bilaterally to the infraorbitary nerve. Results The areas of the R2 components of the BR were significantly suppressed at each time interval tested after TNS ( p Conclusions 20-min TNS did not affected the R1 component of the BR, while inducing a long lasting inhibition of the R2 component, possibly through a long-term depression (LTD)-like mechanism. The different effect on the two components of the BR suggests that only polysynaptic brainstem pathways may be modulated by TNS. Key message TNS is a useful tool to investigate the LTD-like plasticity of brainstem polysynaptic circuits in healthy subjects.