The polymer thick film organic substrate (PTFOS) flexible electrode set.

<p>(<b>A</b>) Image, (<b>B</b>) layout and (<b>C</b>) sectional cut of the PTFOS. The 4 layers are made of dielectric, carbon, silver and Gelfilm.</p

Stimulation studies of the PTFOS electrodes set.

<p>Comparison between 50 Hz current stimulation with a pulse duration of 1 ms for stainless steel set (<b>A</b> and expanded in <b>C</b>) and the PTFOS (<b>B</b> and expanded in <b>E</b>) and 0.1 ms for stainless steel set (<b>D</b>) and the PTFOS (<b>F</b>). Comparison between 50 Hz voltage stimulation with a pulse duration of 1 ms for stainless steel set (<b>G</b>) and the PTFOS (<b>I</b>) and 0.1 ms for stainless steel set (<b>H</b>) and the PTFOS (<b>J</b>).</p

Electrical Impedance spectroscopy study of the traces.

<p>Resistivity of the PTF traces from 100 Hz to 200 MHz.</p

The geometric model used in the electromagnetic simulations.

<p>(<b>A</b>) The shield, MRI birdcage coil and phantom model used in the Finite Differences Time Domain (FDTD) simulations. Detail model of the (B) PTFOS electrode set and (C) the standard Platinum electrode set.</p

Electrical properties and mass density of the electrodes.

<p>Electrical properties and mass density of the electrodes.</p

Results of the electromagnetic simulations.

<p>The <b>B₁</b> field distribution in a plane inside the head coil and phantom containing: (<b>A</b>) no electrodes, (<b>B</b>) platinum and (<b>C</b>) PTFOS electrodes. The 0dB (red) scale corresponds to a reference value of 3.8 10⁻⁷ T.</p

Validation analysis of the electromagnetic simulations.

<p>Numerical estimation (top) vs. AFI measurements (bottom) of the flip angle in the: (<b>A</b>) xy (<b>B</b>) xz and (<b>C</b>) yz planes.</p

Resistivity @100Hz of each electrode/lead.

<p>Numbers refer to drawings in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041187#pone-0041187-g001" target="_blank"><b>Fig. 1</b></a>. (*) Electrode 9 was retested after 3 months in saline solution and exhibited a 5.1 kΩ resistivity.</p

Recordings studies of the PTFOS electrodes set.

<p>Comparison between electrical recording of a Sin(x)/x function with amplitude of 300 µV of a stainless steel set (<b>A</b> and expanded in <b>C</b>) and the PTFOS (<b>B</b> and expanded in <b>D</b>). Comparison between power density spectrum (PSD) of silent (only noise) recording of a stainless steel set (<b>E</b>) and the PTFOS (<b>F</b>).</p

DataSheet1_Short-pulsed micro-magnetic stimulation of the vagus nerve.pdf

Vagus nerve stimulation (VNS) is commonly used to treat drug-resistant epilepsy and depression. The therapeutic effect of VNS depends on stimulating the afferent vagal fibers. However, the vagus is a mixed nerve containing afferent and efferent fibers, and the stimulation of cardiac efferent fibers during VNS may produce a rare but severe risk of bradyarrhythmia. This side effect is challenging to mitigate since VNS, via electrical stimulation technology used in clinical practice, requires unique electrode design and pulse optimization for selective stimulation of only the afferent fibers. Here we describe a method of VNS using micro-magnetic stimulation (µMS), which may be an alternative technique to induce a focal stimulation, enabling a selective fiber stimulation. Micro-coils were implanted into the cervical vagus nerve in adult male Wistar rats. For comparison, the physiological responses were recorded continuously before, during, and after stimulation with arterial blood pressure (ABP), respiration rate (RR), and heart rate (HR). The electrical VNS caused a decrease in ABP, RR, and HR, whereas µM-VNS only caused a transient reduction in RR. The absence of an HR modulation indicated that µM-VNS might provide an alternative technology to VNS with fewer heart-related side effects, such as bradyarrhythmia. Numerical electromagnetic simulations helped estimate the optimal coil orientation with respect to the nerve to provide information on the electric field’s spatial distribution and strength. Furthermore, a transmission emission microscope provided very high-resolution images of the cervical vagus nerve in rats, which identified two different populations of nerve fibers categorized as large and small myelinated fibers.</p