Development of dynamic brain stimulation as a future tool for cortical sensory neuroprostheses
Final Report Abstract
Sensory cortical microstimulation is a promising tool for future 'sensory' (stimulating) cortical neuroprostheses to alliviate loss of peripheral sensation, i.e. due to damage in the sensor organ or on the ascending sensory pathway. Based on the finding that neocortex stimulation is strongly context dependent we investigated the idea that by measuring aspects of the context and use it in real time to adapt stimulus parameters we are able to improve perception of cortical microstimulation. As a first step, we performed a systematic search for stimulation sites that would most effectively drive perception. We found that middle ranges of cortical depth, close to layer 4, the main entry site of ascending thalamic sensory signals, has perceptual effects that exceed those in supraogranular- but also infragranular sites by far. We next succesfully established the soft- and hardware requirements for dynamic brain stimulation, which realizes microstimulation in closed loop fashion based on LFP signals recorded near the location of stimulation. We successfully applied this method in anesthestized animals and then persued the goal towards a proof of principle demonstration for percpetional effects in awake operantly conditioned rats. We were able to demonstrate first evidence for a perceptional benefit of dynamic brain stimulation. To substantiate DBS and make its performence more robust, the algorithm has to be improved to update the classifciation model on the run while the individual is performing to avoid rundown of the model.
Publications
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(2009). Aktuelle Informationstechnische Probleme Sensorischer Kortikaler Neuroprothesen. In Neurotechnik und Neuroethik (edited by Rosenzweig R). Mentis Verlag, Paderborn
Schwarz C.
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(2010) A miniaturized chronic microelectrode drive for awake behaving head restrained mice and rats. J. Neurosci. Meth., 187:67-72
Haiss, F., Butovas, S., Schwarz, C.
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(2010) The head-fixed behaving rat – procedures and pitfalls. Somatosensory & Motor Research, 27:131-48
Schwarz, C., Hentschke, H., Butovas, S., Haiss, F., Stüttgen, M.C., Gerdjikov, T.V., Bergner, C.G. Waiblinger, C.
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(2011) Real-time adaptive microstimulation increases reliability of electrically evoked cortical potentials. IEEE Trans. Biomed. Eng., 58: 1483-149
Brugger, D., Butovas, S., Bogdan, M., Schwarz, C.
