Microelectrode cluster technology for precise interactions with neuronal circuits. Towards highly specific adaptive deep brain stimulation.
Author
Summary, in English
To this end, we have developed a new generation of ultrathin flexible electrode arrays based on 12.5 µm thin wires embedded in a gelatin vehicle providing structural support during implantation. The gelatin embedded electrodes were implanted in rat brains via a narrow track line and spread out as a cluster in the target area. In the first study, we evaluated the performance of the neural recordings for eight weeks with respect to impedance, signal amplitudes and noise levels. We found impedance, and signal to noise ratio of single units to be quite stable, suggesting high biocompatibility. In the second study, we developed a gelatin embedded microelectrode array consisting of 16 microelectrodes, distally equipped with silicone cushions to reduce vascular damage. This array was implanted medial to the subthalamic nucleus, in 6-hydroxydopamine lesioned rats (a classical animal model for Parkinson’s disease), and the effects of deep brain stimulation were evaluated for 6 weeks. Stimulation with subsets of 4-8 electrodes evoked specific motor behaviors in all the tested rats. Depending on the exact electrode combination, stimulation elicited either improvement of locomotion, or grooming and rearing, increased turning, dyskinesia, or no movement. These results suggest that improved stimulation specificity can be obtained by choosing the right group of electrodes from the cluster. In the third study, we hypothesized that reducing the tissue resistance during the insertion of the electrodes would minimize the implantation injury. To address this problem, we coated gelatin embedded needles with a layer of ice, which on melting, provided a super slippery surface during insertion into the brain. The addition of a layer of melting ice decreased the insertion force by approximately 50%, significantly reduced neuronal loss, as well as the astrocytic response, but did not have any obvious effect on microglial activation.
In conclusion, this thesis presents a novel design for implantable and biocompatible neuro-electronic interfaces comprising highly flexible microelectrodes rendering stable recording properties and improved stimulation specificity. In addition, a novel implantation vehicle was developed to reduce the acute tissue reactions in response to the implantation
Department/s
Publishing year
2020
Language
English
Publication/Series
Lund University, Faculty of Medicine Doctoral Dissertation Series
Issue
2020:126
Full text
Document type
Dissertation
Publisher
Lund University, Faculty of Medicine
Topic
- Neurosciences
- Medical Equipment Engineering
Keywords
- Neuro-electronic interfaceneural interface
- neural interface
- tissue reactions
- deep brain stimulation
- Adaptive DBS
- biocompatibility
- implantation method
- neurosurgical tool
Status
Published
Research group
- Neuronano Research Center (NRC)
Supervisor
- Jens Schouenborg
- Angela Cenci Nilsson
- Per Petersson
- Marcus Granmo
ISBN/ISSN/Other
- ISSN: 1652-8220
- ISBN: 978-91-7619-989-3
Defence date
30 November 2020
Defence time
09:00
Defence place
Hörsalen Medicon Village, Scheleevägen 2, Byggnad 302, Lund
Opponent
- Johan Wessberg (professor)