Algorithms for inhibition and desynchronization of neural systems

The dissertation deals with excitable and oscillatory neural systems. A prominent feature of neural activity is oscillations. Through the electrical interaction, neurons tend to synchronize their rhythms and approach a coherent behaviour. On the one hand synchronous neural behaviour relates with such crucial brain functions as vision and memory, while on other hand pathological synchronization may lead to epileptic seizures or symptoms of the Parkinson’s disease. Some patients of the Parkinson disease find an effective way to suppress involuntary movement of limbs by the electrical deep brain stimulation (DBS) – a procedure, when high-frequency electrical pulses are delivered to specific brain areas through implanted electrodes. Despite long and successful history of DBS, its mechanisms are still not fully understood. In the dissertation various perturbation methods were adopted in order to understand an influence of the high-frequency stimulation (HFS) on pulse propagation in neuron. It is shown that, the pulse parameters can be efficiently controlled by a HFS current. The dissertation also analyses the problem of the synchronization suppression. For that purpose an act-and-wait algorithm was suggested, which is based on the idea of intermittent delayed feedback. The main advantage of act-and-wait algorithm is that it can be implemented in the situations, where the stimulation signal is much higher than the signal generated by the system