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64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

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A chronic animal model for the functional evaluation of a fully implantable μECoG-based brain-machine interfacing device

Meeting Abstract

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  • Mortimer Gierthmuehlen - Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg, Freiburg, Germany
  • Xi Wang - Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, Universität Freiburg, Freiburg, Germany; Sektion Epilepsiediagnostik, Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg, Freiburg, Germany
  • Thomas Freiman - Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg, Freiburg, Germany
  • Joerg Haberstroh - CEMT, Experimentelle Chirurgie, Universitätsklinikum Freiburg, Freiburg
  • Joern Rickert - Bernstein Center Freiburg (BCF), Freiburg, Germany; Cortec GmbH, Freiburg, Germany
  • Martin Schuettler - Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering, Universität Freiburg, Freiburg, Germany; Cortec GmbH, Freiburg, Germany
  • Tonio Ball - Sektion Epilepsiediagnostik, Abteilung Allgemeine Neurochirurgie, Universitätsklinikum Freiburg, Freiburg, Germany; Bernstein Center Freiburg (BCF), Freiburg, Germany

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocMO.15.03

doi: 10.3205/13dgnc128, urn:nbn:de:0183-13dgnc1287

Published: May 21, 2013

© 2013 Gierthmuehlen et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective: Epicortically recorded micro-electrocorticography (μECoG) is one of the most promising candidate signals for the development of brain-machine interfaces (BMIs) due to the good compromise between invasiveness and resolution offered by μECoG. The aim of the present study was to develop an animal model for the evaluation of safety and function of a fully implantable, μECoG-based BMI device with a wireless transcutaneous interface.

Method: A 0.4 mm thick 19 mm x 33 mm medical silicone grid with 32 platinum-iridium electrodes was connected to a wirelessly powered infrared half-duplex optical interface with 16-bit range and 1-kHz sampling rate. In both acute and chronic settings, the grid was placed on the somatosensory cortex of anesthetized sheep. The internal unit of the interface was placed subcutaneously. Electric and mechanic stimulation was performed on four different stimulation points of the sheep’s face. Somatosensory evoked potentials (SEPs) were recorded on the cortex. Four weeks after implantation, electric stimulation was repeated under anesthesia. 16 weeks after surgery, mechanic stimulation was performed in the awake animals.

Results: Cortical brain responses were detectable with a high signal-to-noise ratio in all animals. Significant SEPs were recorded during electrical stimulation and revealed a clear somatotopic organisation within the somatosensory cortex. SEPs were reliably recordable 0, 4 and 16 weeks after implantation. An efficacious transcutaneous power supply and transmission could be established without problems.

Conclusions: We developed a fully implantable μECoG system for BMI purposes and successfully tested it in a new chronic implantation animal model over 4 months. SEPs could be reliably recorded. Thus, our animal model allows chronic evaluation both of safety and function of the wireless implant. Against the background of declining primate research, application of the sheep animal model as used in the present study could be broadened to other fields of neuroscience.

This work was funded by BMBF grant “Braincon” (0316064C).