- Modeling studies to investigate the influence of the stimulation mechanisms on the desynchronizing effects
- Influence of electrical stimulation on the physiological signal processing
- Optimization of the methods for the therapeutic neuromodulation and transfer to clinical application
Modeling studies to investigate the influence of the stimulation mechanisms on the desynchronizing effects
This project is devoted to the investigation of the anti-kindling effect observed for different stimulation strategies, standard high-frequency (HF) stimulation, coordinated reset (CR®) stimulation and approaches using delayed-feedback stimulation of neuronal activity. The investigations are performed utilizing mathematical models of the anatomical target structures.
Different stimulation mechanisms might activate a variety of neuronal structures mediating inhibitory or excitatory effects. The reaction of the neuronal dynamics can be quite different depending on the detailed stimulation mechanisms. For example, in a study conducted in the last years (Hauptmann & Tass, BioSystems 2007) we showed that purely excitatory stimulation mechanisms result in a long-lasting reduction of the pathologic synchronization for both HF- and CR®-stimulation. The neuronal plasticity has to be considered to observe the long-lasting effects. In the presence of a mixture of different stimulation effects, long-lasting therapeutic effects are only reliably observed for the novel CR® stimulation.
P.A. Tass and C. Hauptmann Anti-kindling achieved by stimulation targeting slow synaptic dynamics Restorative Neurology and Neuroscience,Vol. 27(6), 589-609 (2009).
C. Hauptmann, P.A. Tass Cumulative and after-effects of short and weak coordinated reset stimulation: a modeling study Journal of Neural Engineering, Vol. 6, 016004 (2009).
C. Hauptmann, O. Popovych & P.A. Tass, Desynchronizing the abnormally synchronized neural activity in the subthalamic nucleus - a modeling study, Expert Review of Medical Devices 4(5) 633-650 (2007).
C. Hauptmann, O. Omelchenko, O.V. Popovych, Y. Maistrenko & P.A. Tass, Control of spatially patterned synchrony with multisite delayed feedback, Physical Review E, Vol. 76, 066209 (2007).
P.A. Tass & C. Hauptmann, Therapeutic modulation of synaptic connectivity with desynchro- nizing brain stimulation, International Journal of Psychophysiology, Vol. 64, 53-61 (2007).
C. Hauptmann & P.A. Tass, Therapeutic rewiring by means of desynchronizing brain stim- ulation, Biosystems, Vol. 89, 173-181 (2007).
C. Hauptmann, O. Popovych & P.A. Tass, Demand-controlled desynchronization of oscilla- tory networks by means of a multisite delayed feedback stimulation, Computing and Visual- ization in Science, Vol. 10(2), 71-78 (2007).
P.A. Tass & C. Hauptmann, Therapeutic rewiring by means of desynchronizing brain stim- ulation, Nonlinear Phenomena in Complex Systems, Vol. 9(3), 298-312 (2006).
C. Hauptmann, O. Popovych & P.A. Tass, Effectively desynchronizing deep brain stimula- tion based on a coordinated delayed feedback stimulation via several sites: a computational study, Biol. Cybern., Vol. 93, 463-470 (2005).
C. Hauptmann, O. Popovych & P.A. Tass, Multi-Site Coordinated Delayed Feedback for an Effective Desynchronization of Neuronal Networks, Stochastics and Dynamics, Vol. 5, No. 2, 307-319 (2005).
C. Hauptmann, O. Popovych & P.A. Tass, Delayed Feedback Control of Synchronization in Locally Coupled Neuronal Networks, Neurocomputing, Vol. 65-66, 759-767 (2005).
Influence of electrical stimulation on the physiological signal processing
The loss of segregation of neuronal signal processing pathways is an important hypothesis to explain the origin of functional deficits as associated with Parkinson’s disease. In this project we use a modeling approach, which is utilized to study the influence of deep brain stimulation on the restoration of segregated activity in the target structures. Besides the spontaneous activity of the target network, the model considers a weak sensory input mimicking signal processing tasks, electrical deep brain stimulation delivered through a standard DBS electrode and synaptic plasticity. We can demonstrate that the sensory input is capable of inducing a modification of the network structure, which results in segregated microcircuits if the network is initialized in the healthy, desynchronized state. Depending on the strength and coverage, the sensory input is capable of restoring the functional sub-circuits even if the network is initialized in the synchronized, pathological state. Weak coordinated reset stimulation, applied to a network featuring a loss of segregation caused by global synchronization, is able to restore the segregated activity and to truncate the pathological, synchronized activity.
C. Hauptmann, P.A. Tass Restoration of segregated, physiological neuronal connectivity by desynchronizing stimulation J Neural Eng. Vol. 7, 056008 (2010).
Optimization of the methods for the therapeutic neuromodulation and transfer to clinical application
This project is devoted to technically optimize the theoretical approaches developed in the institute in the last years. After optimization the approaches are transferred to clinical application. The stimulation strategies developed by INM-7 can be used for example for the treatment of Parkinson’s disease and Tinnitus. The neurotechnology group supports the corresponding proof-of-concept studies. The studies show, that the optimization of the stimulation devices and methods has great potential to further improve the therapeutic outcome of the stimulation. Therefore, each component of the stimulation system, from the stimulation lead to the pulse generator, is investigated in detail. Optimization potentials are pinpointed. Mathematical models of neuronal target populations, finite-element methods for the calculation of the spread of electrical fields, imaging techniques and experimental studies are used to investigate the necessary optimization steps.
C. Hauptmann, J.C. Roulet, J.J. Niederhauser, W. Dll, M.E. Kirlangic, B. Lysyansky, V. Krachkovskyi, M.A. Bhatti, U.B. Barnikol, L. Sasse, C.P. Bhrle, E.-J. Speckmann, M. Gtz, V. Sturm, H.- J. Freund, U. Schnell and P.A. Tass External trial deep brain stimulation device for the application of desynchronizing stimulation techniques Journal of Neural Engineering, Vol. 6, 066003 (2009).
P.A. Tass, A.N. Silchenko, C. Hauptmann, U.B. Barnikol and E.-J. Speckmann Long-lasting desynchronization in rat hippocampal slice induced by coordinated reset stimulation Physi- cal Review E, Vol. 80, 011902 (2009).
J. Buhlmann, L. Hofmann, P.A. Tass and C. Hauptmann Modeling of a segmented electrode for desynchronizing deep brain stimulation Frontiers in Neuroengineering, Vol. 4 (2011)
At the moment projects in the following fields are conducted in the neurotechnology group:
- Optimization of the lead design allowing current steering