Neural implants

We develop neuroelectrodes that enable medically safe, high-resolution electrophysiological measurement and stimulation of neuronal activity in the central nervous system. One focus is the further development of electrode technology for use as a neuroelectrical interface, e.g. for adaptive deep brain stimulation, DBS) or central hearing prostheses. For this purpose, we apply different behavioral paradigms. In addition, we are investigating approaches for the prevention and treatment of implant infections.

Research

Functional neurosurgery - electrode technique

Neuroelectrodes, which provide permanent, medically safe, high-spatial-resolution electrophysiological measurement and stimulation in the central nervous system, are used as neuroelectric interfaces, e.g., in deep brain stimulation or as central auditory prostheses.
In deep brain stimulation (DBS), electrodes are implanted in specific brain regions where they are permanently electrically stimulated. This is a highly effective and established therapy for movement disorders such as Parkinson's disease. DBS is becoming increasingly important for neuropsychiatric disorders.
The mechanisms of action of DBS, in particular their influence on the pathophysiology of the respective disease, are not yet fully understood. To explore these mechanisms, we use animal models to better understand the complex interaction of DBS with neuronal functional loops of the brain under normal and pathological conditions. We use the resulting information to further develop and improve treatments for DBS.

Within the framework of a DFG (German Research Foundation) funded cooperation with the Barcikowski group, Technical Chemistry I of the University-Duisburg Essen, we have shown that the deposition of platinum-iridium nanoparticles contributes to the impedance optimization of lead and stimulation electrodes without affecting the biocompatibility of the electrodes. Currently, we are investigating whether the quality of electrophysiological conduction can be improved by such a coating.
As part of an EU-approved research project led by Prof. Doll (Fraunhofer Institute for Toxicology and Experimental Medicine ITEM Translational Biomedical Engineering), novel electrode arrays will be implanted in rats to chronically record cortical activity similar to EEG but with higher resolution. Such electrode arrays can later be used to derive neuronal activity in the context of adaptive DBS.

More information
Prof. Dr. Kerstin Schwabe (schwabe.kerstin@mh-hannover.de)
Prof. Dr. Joachim K. Krauss (krauss.joachim@mh-hannover.de)

Selected literature

Ramesh V, Rehbock C, Giera B, Karnes JJ, Forien JB, Angelov SD, Schwabe K, Krauss JK, Barcikowski S. Comparing Direct and Pulsed-Direct Current Electrophoretic Deposition on Neural Electrodes: Deposition Mechanism and Functional Influence. Langmuir. 2021 Aug 6.

Koenen S, Rehbock C, Heissler HE, Angelov SD, Schwabe K, Krauss JK, Barcikowski S. Optimizing in Vitro Impedance and Physico-Chemical Properties of Neural Electrodes by Electrophoretic Deposition of Pt Nanoparticles. Chemphyschem. 2017 May 5;18(9):1108-1117.

Angelov SD, Koenen S, Jakobi J, Heissler HE, Alam M, Schwabe K, Barcikowski S, Krauss JK. Electrophoretic deposition of ligand-free platinum nanoparticles on neural electrodes affects their impedance in vitro and in vivo with no negative effect on reactive gliosis. J Nanobiotechnology. 2016 Jan 12;14:3.

Cooperations
Prof. Dr. Holger Blume (Institute for Microelectronics, LUH)
Prof. Dr. Theodor Doll (Department of Otolaryngology, MHH)
Prof. Dr. Stephan Barcikowski, Dr. Christoph Rehbock (Institute for Technical Chemistry, University of Duisburg-Essen)

Promotion
MDOT-Proposal-SEP-210512779
DFG - KR 2931/3-3

Implant infections

Implant-associated infections are a major cause of implant failure and a major challenge in many surgical settings. Usually, these infections are triggered by bacteria that attach to the implant surface, organize into complex biofilms, and induce chronic inflammation with destructive changes in the surrounding tissue. Systemic drug therapy is rarely successful because bacteria organized in biofilms are often resistant to antibiotics and the body's own immune defenses.
In our group, we have established a rodent model in which, after infection of a transcranial (through the skull bone) screw with biofilm pathogens, a self-sustaining biofilm formation with associated local inflammatory reaction of the surrounding tissue occurs. This model is suitable for preclinical screening of new implant materials and surfaces before their suitability is verified in more elaborate procedures. For example, we use this animal model to investigate the effect of a release of antibacterial agents by functionalized implant surfaces in biofilm-associated infections.

Furthermore, we follow the course of implant infections with a thermal imaging camera. With this technique, it may be possible to detect any morphological changes in the skull bone and surrounding tissue at an early stage and prevent implant loss through timely treatment.

More information
Prof. Dr. K. Schwabe (schwabe.kerstin@mh-hannover.de)

Selected literature
Sun J, Eberhard J, Glage S, Held N, Voigt H, Schwabe K, Winkel A, Stiesch M. Development of a peri-implantitis model in the rat. Clin Oral Implants Res. 2020 Mar;31(3):203-214.

Hong B, Winkel A, Stumpp N, Abdallat M, Saryyeva A, Runge J, Stiesch M, Krauss JK. Detection of bacterial DNA on neurostimulation systems in patients without overt infection. Clin Neurol Neurosurg. 2019 Sep;184:105399. d

Glage S, Paret S, Winkel A, Stiesch M, Bleich A, Krauss JK, Schwabe K. A new model for biofilm formation and inflammatory tissue reaction: intraoperative infection of a cranial implant with Staphylococcus aureus in rats. Acta Neurochir (Vienna). 2017 Sep;159(9):1747-1756.

Hong B, Winkel A, Ertl P, Stumpp SN, Schwabe K, Stiesch M, Krauss JK. Bacterial colonization of suture material after routine neurosurgical procedures: relevance for wound infection. Acta Neurochir (Vienna). 2018 Mar;160(3):497-503.

Cooperations
Prof. Dr. Andre Bleich, Dr. Silke Glage (Institute of Laboratory Animal Science and Central Animal Laboratory, MHH)
Prof. Dr. Meike Stiesch, Dr. Andreas Winkel (Clinic for Dental Prosthetics, MHH)
Prof. Dr. Peter Behrens (Institute for Inorganic Chemistry, LUH)
Prof. Dr. Michael Czaplik (Clinic for Anesthesiology, University Hospital Aachen)

Promotion
DFG Research Group 2591 - SCHW1176/7-1

Central processing of auditory information

We are interested in the processing of auditory information in fronto-basal ganglia-thalamic brain regions and their interaction with the central auditory pathway. Recordings from basal ganglia-thalamic regions during an auditory oddball and a speech processing paradigm provided two insights: first, processing of auditory information already occurs at the subcortical level. Second, behaviorally relevant information is transmitted from there to cortical regions. In patients, the derivation of neural activity can only occur in regions selected for medical purposes. Therefore, we established the auditory oddball paradigm with a target, a distractor, and a standard tone of different frequencies in rats. Initial neural derivations show that the elicited potentials resemble those of our patients. In addition, we use the oddball paradigm to test the optimal stimulation strategy of central auditory implants in a behavioral paradigm.

Hearing loss in adults is considered a risk factor for the development of dementia. However, it is not yet clear whether this is due to the social withdrawal of the patients or to a change in neuronal networks triggered by the hearing loss with resulting cognitive disorders. To investigate this question independently of the actual speech ability, we are interested in possible changes in behavior and neuronal activity after hearing loss in rats. Preliminary studies show a long-term learning and memory deficit, as well as decreased social interactions, in deafened adult rats. Due to the progressive interconnectedness of the maturing brain, damage in early developmental stages leads not only to local disturbances, but also to malformations of neural circuits. This can be associated with behavioral deficits and even neuropsychiatric disorders. Therefore, another approach is to study behavior and neuronal activity after hearing loss in juvenile rats.

More information
Prof. Dr. Kerstin Schwabe (schwabe.kerstin@mh-hannover.de)

Selected literature
Knipper M, van Dijk P, Schulze H, Mazurek B, Krauss P, Scheper V, Warnecke A, Schlee W, Schwabe K, Singer W, Braun C, Delano PH, Fallgatter AJ, Ehlis AC, Searchfield GD, Munk MHJ, Baguley DM, Rüttiger L. The Neural Bases of Tinnitus: Lessons from Deafness and Cochlear Implants. J Neurosci. 2020 Sep 16;40(38):7190-7202.

Beck AK, Sandmann P, Dürschmid S, Schwabe K, Saryyeva A, Krauss JK. Neuronal activation in the human centromedian-parafascicular complex predicts cortical responses to behaviorally significant auditory events. Neuroimage. 2020 May 1;211:116583.

Beck AK, Lütjens G, Schwabe K, Dengler R, Krauss JK, Sandmann P. Thalamic and basal ganglia regions are involved in attentional processing of behaviourally significant events: evidence from simultaneous depth and scalp EEG. Brain Struct Funct. 2018 Jan;223(1):461-474.

Schepers IM, Beck AK, Bräuer S, Schwabe K, Abdallat M, Sandmann P, Dengler R, Rieger JW, Krauss JK. Human centromedian-parafascicular complex signals sensory cues for goal-oriented behavior selection. Neuroimage. 2017 May 15;152:390-399.

Cooperations
Prof. Thomas Lenarz, PD Verena Scheper (Department of Otolaryngology, MHH)
Prof. Andrej Kral (Institute of AudioNeuroTechnology, VIANNA)
Prof. Georg Klump (Department of Neuroscience, UOL)
Prof. Jochem Rieger (Department of Psychology, Applied Neurocognitive Psychology, UOL).
Prof. Christiane Thiel (Department of Psychology, Biological Psychology, UOL)
Prof. Esther Ruigendijk (Institute of Dutch Studies, UOL)
Promotion
Cluster of Excellence H4a

GROUP LEADER

Prof. Dr.

Kerstin Schwabe

Experimental Neurosurgery of the Department of Neurosurgery

PD Dr.

Mesbah Alam

Dr.

Svilen Angelov

Dr. rer. nat.

Simeon Helgers

Prof. Dr.

Joachim K. Krauss

Clinic Director, Deputy Group Leader

Publications

Schwabe K, Alam M, Saryyeva A, Lütjens G, Heissler HE, Winter L, Heitland I, Krauss JK, Kahl KG. Oscillatory activity in the BNST/ALIC and the frontal cortex in OCD: acute effects of DBS. J Neural Transm. 2021 Feb;128(2):215-224. doi: 10.1007/s00702-020-02297-6.

Beck AK, Sandmann P, Dürschmid S, Schwabe K, Saryyeva A, Krauss JK. Neuronal activation in the human centromedian-parafascicular complex predicts cortical responses to behaviorally significant auditory events. Neuroimage. 2020 May 1;211:116583. doi: 10.1016/j.neuroimage.2020.116583.

Glage S, Paret S, Winkel A, Stiesch M, Bleich A, Krauss JK, Schwabe K. A new model for biofilm formation and inflammatory tissue reaction: intraoperative infection of a cranial implant with Staphylococcus aureus in rats. Acta Neurochir (Vienna). 2017 Sep;159(9):1747-1756. doi: 10.1007/s00701-017-3244-7.

Koenen S, Rehbock C, Heissler HE, Angelov SD, Schwabe K, Krauss JK, Barcikowski S. Optimizing in Vitro Impedance and Physico-Chemical Properties of Neural Electrodes by Electrophoretic Deposition of Pt Nanoparticles. Chemphyschem. 2017 May 5;18(9):1108-1117. doi: 10.1002/cphc.201601180.

Keywords

Neuroelectrodes, electrophysiological leads, neuroelectrical interface, behavioral studies, cognition, central auditory prostheses, deep brain stimulation, implant infections.

Contact

Prof. Dr. Kerstin Schwabe

+45 511 532 2862

schwabe.kerstin(at)mh-hannover.de

NIFE
Stadtfelddamm 34
30625 Hanover

Teaching

Lectures

Marschollek M, Schwabe K (2019) Body-mounted and implanted systems measurement of physical functions, interaction interfaces and deep brain stimulation. Presentation at the 1st BWG Symposium "SynENZ - Interaction of Natural and Artificial Intelligence" on February 14 and 15 in Braunschweig.

Schwabe K (2017) Subcortical processing of auditory information. Presentation at the symposium "Closing the auditory (efferent) loop II", May 10-12, Krems, Austria.

Schwabe K (2016) Animal models for Tourette: translational aspects for brain stimulation. Presentation at the symposium "Psychiatric medicine needs new therapeutic avenues - animal models pave the way" at the Annual Congress of the German Society for Biological Psychiatry, September 22-24, 2016 in Würzburg.

More additional info

Cluster of Excellence H4a2.0; DFG FOR 2591 - TP12 SCHW1176/7-2; DFG - KR 2931/3-3), EU MDOT

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