@article{HofmannEbertHauptmannetal.2011, author = {Hofmann, Lorenz and Ebert, Martin and Hauptmann, Peter Alexander and Hauptmann, Christian}, title = {Modified pulse shapes for effective neural stimulation}, volume = {4}, pages = {9}, journal = {Frontiers in Neuroengineering}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, doi = {https://doi.org/10.3389/fneng.2011.00009}, year = {2011}, abstract = {The electrical stimulation of neuronal structures is used as a treatment for many neurological disorders, e.g., for the treatment of Parkinson's disease via deep brain stimulation (DBS). To reduce side effects, to avoid tissue or electrode damage, and to increase battery lifetimes, an effective but gentle electrical stimulation is of prime importance. We studied different modified pulse shapes for application in DBS with respect to their efficiency to initiate neuronal activity. Numerical simulations of two mathematical neuron models were performed to investigate the effectiveness of different modified pulse shapes. According to our results, the pulse shapes considered showed a considerably increased efficiency in terms of both activation and entrainment of neural activity. We found that the introduction of a gap with a specific and optimized duration in a biphasic pulse and the reversal of the standard pulse phase order yielded stimulation protocols that could increase the efficiency and therefore reduce the energy consumption of stimulation. The improvements were achieved by simple modifications of existing stimulation techniques. The modification of the pulse shapes resulted in an improvement of up to 50\% for both the activation of resting neurons and the entrainment of bursting neurons.}, language = {en} } @article{EbertHauptmannTass2014, author = {Ebert, Martin and Hauptmann, Christian and Tass, Peter Alexander}, title = {Coordinated reset stimulation in a large-scale model of the STN-GPe circuit}, volume = {8}, pages = {154}, journal = {Frontiers in Computational Neuroscience}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1662-5188}, doi = {https://doi.org/10.3389/fncom.2014.00154}, year = {2014}, abstract = {Synchronization of populations of neurons is a hallmark of several brain diseases. Coordinated reset (CR) stimulation is a model-based stimulation technique which specifically counteracts abnormal synchrony by desynchronization. Electrical CR stimulation, e.g., for the treatment of Parkinson's disease (PD), is administered via depth electrodes. In order to get a deeper understanding of this technique, we extended the top-down approach of previous studies and constructed a large-scale computational model of the respective brain areas. Furthermore, we took into account the spatial anatomical properties of the simulated brain structures and incorporated a detailed numerical representation of 2 ยท 104 simulated neurons. We simulated the subthalamic nucleus (STN) and the globus pallidus externus (GPe). Connections within the STN were governed by spike-timing dependent plasticity (STDP). In this way, we modeled the physiological and pathological activity of the considered brain structures. In particular, we investigated how plasticity could be exploited and how the model could be shifted from strongly synchronized (pathological) activity to strongly desynchronized (healthy) activity of the neuronal populations via CR stimulation of the STN neurons. Furthermore, we investigated the impact of specific stimulation parameters especially the electrode position on the stimulation outcome. Our model provides a step forward toward a biophysically realistic model of the brain areas relevant to the emergence of pathological neuronal activity in PD. Furthermore, our model constitutes a test bench for the optimization of both stimulation parameters and novel electrode geometries for efficient CR stimulation.}, language = {en} }