Michael Bodo, Ryan Sheppard, Aaron Hall, Martin Baruch, Melissa Laird, Shravalya Tirumala and Richard Mahon
by the Walter Reed Army Institute of Research (DataLyser). Data were acquired at a 200 Hz sampling rate.
The head of each rat was secured by a gas anesthesia head holder (designed for rats) of the stereotaxic frame (David Kopf Instruments, Tujunga, CA). The skin was removed to expose the cranium between the sutura frontalis and the sutura lambda. The exposed bone was rinsed with hydrogen peroxide in preparation for the application of acrylic adhesive. Four burr holes (0.8 mm) were drilled for insertion of intracranial electrodes (E 363 / 1, Plastics One, Roanoke
Kathrin Badstübner, Marco Stubbe, Thomas Kröger, Eilhard Mix and Jan Gimsa
most important target regions for the treatment of PD in humans. The tip coordinates relative to bregma were: anterior-posterior (AP) = -3.5 mm, medial-lateral (ML) = 2.4 mm and dorsalventral (DV) = -7.6 mm (Paxinos and Watson, 2007). The electrodes were fixed to the skull by an adhesive-glue bridge of dental acrylic (Pontiform automix 10:1, Müller & Weygandt GmbH, Büdingen, Germany), including an anchor screw that was tightened to the skull on the left hemisphere. Figure 4 illustrates the unipolar electrode model.
Implanted unipolar DBS electrode
Michael Bodo, Leslie D. Montgomery, Frederick J. Pearce and Rocco Armonda
the right side of skull above and below the fronto-parietal sutura.
Electrodes were fixed to the skull with Vetbond tissue adhesive (3M, St. Paul, MN) and instant adhesive 454 (Loctite, Hartford, CT). Data were sampled with 200 Hz analogue digital conversion rate using a DREW system (Institute of Surgical Research, San Antonio, TX) and a DASH-18 (Astro-Med, West Warwick, RI) with an analogue digital converter card (PCI 6052E, National Instruments, Austin, TX) with 16 bit resolution. Serial port data sampling rate was 12 samples per minute. Data were processed
Parvind K Grewal, Majid Shokoufi, Jeff Liu, Krishnan Kalpagam and Kirpal S Kohli
the 1 mA safe current limit was never exceeded, in accordance with the American National Standard: Safe current limits for electromedical apparatus guidelines [ 15 ]. The highest impedance variability at low frequencies coming from “stratum corneum” was compensated by use of pre-gelled Ag/AgCl electrodes with conductive adhesive hydrogel from Kendall TM that were non-polarizable and generate less than 10μV noise, hence preferred for skin surface measurements. Prior skin preparation was done as the quality of contact is reduced by a factor of 10 without proper
The exposed bone was rinsed with hydrogen peroxide in preparation for the application of acrylic adhesive. Burr holes (0.8 mm) were drilled for both EEG (left side) and REG (right side) intracranial electrodes (E 363 / 1, Plastics One, Roanoke, VA) before a 2-mm distance from the sutura lambdoidea, and a 2-mm distance lateral to the sutura sagittalis. Frontal electrodes were placed 2 mm behind the sutura coronalis. Inter-electrode distance was 6 mm. Burr hole was drilled between both EEG and both REG electrodes with 2.3 mm drill bit for a 18 g needle insertion
J.C. Marquez, M. Rempfler, F. Seoane and K. Lindecrantz
/AgCl Electrolytic Gel Electrode
Red Dot repositionable electrodes manufactured by 3M were used in this study. The rectangular electrodes with a contact area of 10.1cm 2 and snap-button connectors, utilize conductive and adhesive hydro gel to ensure correct contact.
C ECG and ICG Measurements
For this study a TEB-measurement one-minute in duration was recorded on three healthy subjects standing in a resting state and following the measurement protocol presented in Fig.2 . Using the textrode belt set and conventional Ag/AgCl electrodes, single frequency measurements at 50
mask and cut to size before being attached to the substrate using double sided 10 μm thickness adhesive tape (Adhesives Research, USA). The geometry of the electrodes is shown in Fig. 3 :
Schematic and geometry of the impedance sensor.
The PDMS layer was formed by first creating a negative master mould from SU-8 2150 (Microchem, USA). The 500 μm thick SU-8 mould was patterned using photo-lithography on a silicon wafer. The PDMS was formed from a two part mix (Sylgard 184, Dow Corning, USA) and poured into the mould and left to cure and outgas for
Sören Weyer, Hannes Weber, Christian Kleeberg, Steffen Leonhardt and Tobias Wartzek
capacitive coupling, and an active capacitive coupling. In order to acquire a conductive coupling to the tissue, conventional ECG-adhesive electrodes were used. For passive capacitive coupling, the same electrodes as for the active coupling (described above) were used, but in this case the circuit-boards were unequipped. To provide three comparable conditions, the gain of the active electrode was set to A EL = 1 by removing the resistor R g , EL . Furthermore, the gain resistor of the differential amplifier was raised to R g , INA = 470 Ω, resulting in a gain of A