tDCS cranial nerve Co-stimulation: Unveiling brainstem pathways involved in trigeminal nerve direct current stimulation in rats

IF 7.6 1区医学 Q1 CLINICAL NEUROLOGY

Brain Stimulation Pub Date : 2025-02-05 DOI:10.1016/j.brs.2025.01.025

Alireza Majdi , Liyi Chen , Lars E. Larsen , Robrecht Raedt , Myles Mc Laughlin

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引用次数: 0

Abstract

Background

The effects of transcranial direct current stimulation (tDCS) are generally thought to result from the polarization of cortical neurons by the weak electric fields it creates. However, recent evidence suggests that some tDCS effects may be mediated through co-stimulation of peripheral or cranial nerves, particularly the trigeminal nerve (TN). The TN projects to key brainstem nuclei that regulate neurotransmitter release throughout the central nervous system, but the specific pathways involved are not yet well understood.

Methods

In this study, we examined the effects of acute transcutaneous TN direct current stimulation (TN-DCS) on tonic (i.e. mean spike rate) and phasic (number of bursts, spike rate per burst, burst duration, and inter-burst interval) activities while simultaneously recording single-neuron activity across three brainstem nuclei in rats: the locus coeruleus (LC; phasic and tonic activities), dorsal raphe nucleus (DRN; tonic activity), and median raphe nucleus (MnRN; tonic activity).

Results

TN-DCS significantly modulated tonic activity in the LC and DRN, with interactions between amplitude, polarity, and time affecting mean spike rates. It also influenced phasic activity in the LC, altering burst number, duration, and inter-burst intervals. In contrast, MnRN tonic activity was unchanged. Blocking TN with xylocaine eliminated the effects on tonic activity in both the LC and DRN.

Conclusions

These results suggest that tDCS may modulate the TN, altering DRN and LC activity. Differential changes in tonic and phasic LC activity highlight their roles in TN-DCS effects on the cortex. This research offers insights to improve tDCS efficacy and understanding. Keywords: tDCS; trigeminal nerve; locus coeruleus; Dorsal raphe nucleus; median raphe nucleus.

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来源期刊

Brain Stimulation 医学-临床神经学

CiteScore

13.10

自引率

9.10%

发文量

256

审稿时长

72 days

期刊介绍： Brain Stimulation publishes on the entire field of brain stimulation, including noninvasive and invasive techniques and technologies that alter brain function through the use of electrical, magnetic, radiowave, or focally targeted pharmacologic stimulation. Brain Stimulation aims to be the premier journal for publication of original research in the field of neuromodulation. The journal includes: a) Original articles; b) Short Communications; c) Invited and original reviews; d) Technology and methodological perspectives (reviews of new devices, description of new methods, etc.); and e) Letters to the Editor. Special issues of the journal will be considered based on scientific merit.