Multi-electrode arrays (MEAs) enable the recording of brain activity without needing to penetrate nerve cell tissue. They are, for example, used in treating epilepsy in patients who do not have the option of undergoing drug therapy and are implemented for the preparation and realization of surgery for the targeted removal of diseased tissue. “Clinically approved MEAs have few, relatively large and relatively far apart electrodes,” explains the head of the study, Dr. Detlef Wegener from the Brain Research Institute at the University of Bremen. “They have a far better spatial definition than EEG measurements. However, they are only suitable for new, clinical fields of applications in a very restricted manner.” In order to reduce the distance to the cells, such mats are placed underneath the hard cerebral membrane, the so-called dura mater. “This is positive for the signal quality but also at the same time means that MEAs can only be implemented for short periods, as the opening of the cerebral membrane can result in clinical complications,” states the scientist.
New Multi-Electrode Arrays Enable Less Invasive Procedure
Wegener and his team therefore view so-called epidural MEAs as being an alternative. “They are mats that are placed above the hard cerebral membrane and in principle can stay there for an unrestricted amount of time as the cerebral membrane does not have to be opened.” This is thus a far less invasive procedure, which could also be used for fully paralyzed patients who may then control a prosthesis with the help of commands that are relayed from the brain to a computer.
Many Small Contact Points That Are Close Together
“However, one problem is that the cerebral membrane is a barrier that worsens the signal quality. When one tries to place the electrodes on top of said membrane, it is necessary to find ways of dealing with the decreased quality so that it is still possible to achieve the clinical goal.” In a new study, which was recently published in the Nature journal “Communications Biology,” University of Bremen researchers show that this is possible with a high level of quality. They implement an electrode mat, which was developed by Professor Andreas Kreiter and Professor Walter Lang as leaders of the “I-See” Creative Unit together with the Brain Research Institute and the Institute for Microsensors, -actuators and -systems (IMSAS). Creative Units are research groups at the university that were funded as part of the Excellence Initiative in order to foster creative ideas. “This mat is fitted with many small contact points that are close together. By combining the information stemming from many electrodes and then assessing said information with the help of artificial intelligence, it is possible to attain a very high level of precision with regard to the underlying neural activity,” explains Wegener.
In a study published in 2019, the researchers were able to show that this procedure is very precise in measuring and classifying brain activity. The current study also investigates whether the smallest differences between visual stimuli, for example in the size and shape of an object, can be classified with the help of epidural signals. According to Wegener, the most recent findings pave the way for the further advancement of the technical development of epidural MEAs, in order to establish them in daily clinical practice. The German Research Foundation (DFG) funded the studies.
Link to the published study in the Communications Biology journal: https://rdcu.be/cl4g6
Dr. Detlef Wegener
Brain Research Institute
University of Bremen
Phone: +49 421 218-63007
Email: wegenerprotect me ?!brain.uni-bremenprotect me ?!.de