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Augmented brain function by coordinated reset stimulation with slowly varying sequences.

Zeitler M, Tass PA - Front Syst Neurosci (2015)

Bottom Line: So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS).In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR.To this end, a sequence is applied many times before randomly switching to the next sequence.

View Article: PubMed Central - PubMed

Affiliation: Research Center Jülich, Institute of Neuroscience and Medicine, Neuromodulation (INM-7) Jülich, Germany.

ABSTRACT
Several brain disorders are characterized by abnormally strong neuronal synchrony. Coordinated Reset (CR) stimulation was developed to selectively counteract abnormal neuronal synchrony by desynchronization. For this, phase resetting stimuli are delivered to different subpopulations in a timely coordinated way. In neural networks with spike timing-dependent plasticity CR stimulation may eventually lead to an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and abnormal synchrony. The spatiotemporal sequence by which all stimulation sites are stimulated exactly once is called the stimulation site sequence, or briefly sequence. So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS). In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR. To this end, a sequence is applied many times before randomly switching to the next sequence. This new method is called SVS CR stimulation, i.e., CR with slowly varying sequences. In a neuronal network with strong short-range excitatory and weak long-range inhibitory dynamic couplings SVS CR stimulation turns out to be superior to CR stimulation with fixed sequences or RVS.

No MeSH data available.


Related in: MedlinePlus

Effect of switching the sequence during CR stimulation. In a series of simulations with different stimulation intensities (K = 0.20 in left panels and K = 0.45 in right panels) the sequence was either kept fixed [FS CR stimulation, (A,B)], randomly varied just once [in the middle of the stimulation period, at t = 32 s, (C,D)] or randomly varied at three equidistant times [at t = 16, 32, 48 s, (E,F)]. Simulations were performed for eleven different sequence orders and initial network conditions. Each panel shows the dynamics of Cav for each of the eleven simulations in a different color. FS CR stimulation (A,B): Time course of Cav for eleven combinations of different initial network conditions and different sequence for SVS-2400, respectively, for K = 0.20 (A) and K = 0.45 (B). Change of sequence in the middle of the stimulation epoch (C,D): Two different sequences, each applied 1200 times in a row. Change of sequence at t = 32 s, with K = 0.20 (C) and K = 0.45 (D). Sequence is changed three times at equidistant times (t =, 16, 32, and 48 s) during the stimulation epoch (E,F): In each simulation four different sequences are applied 600 times in a row, so that after 16 s the next sequence randomly chosen, with K = 0.20 (E) and K = 0.45 (F). The red horizontal bars represent CR-on periods. The vertical dashed-dotted lines indicate a change of sequence. cmax = 1 in all simulations.
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Figure 6: Effect of switching the sequence during CR stimulation. In a series of simulations with different stimulation intensities (K = 0.20 in left panels and K = 0.45 in right panels) the sequence was either kept fixed [FS CR stimulation, (A,B)], randomly varied just once [in the middle of the stimulation period, at t = 32 s, (C,D)] or randomly varied at three equidistant times [at t = 16, 32, 48 s, (E,F)]. Simulations were performed for eleven different sequence orders and initial network conditions. Each panel shows the dynamics of Cav for each of the eleven simulations in a different color. FS CR stimulation (A,B): Time course of Cav for eleven combinations of different initial network conditions and different sequence for SVS-2400, respectively, for K = 0.20 (A) and K = 0.45 (B). Change of sequence in the middle of the stimulation epoch (C,D): Two different sequences, each applied 1200 times in a row. Change of sequence at t = 32 s, with K = 0.20 (C) and K = 0.45 (D). Sequence is changed three times at equidistant times (t =, 16, 32, and 48 s) during the stimulation epoch (E,F): In each simulation four different sequences are applied 600 times in a row, so that after 16 s the next sequence randomly chosen, with K = 0.20 (E) and K = 0.45 (F). The red horizontal bars represent CR-on periods. The vertical dashed-dotted lines indicate a change of sequence. cmax = 1 in all simulations.

Mentions: We analyzed the effect of FS CR stimulation for eleven different initial network conditions in combination with a different sequence for each network, respectively. Figure 6A clearly shows that for the FS CR stimulation (SVS-2400) with K = 0.20, the decrease of Cav strongly depends on which sequence is used. Pronounced long-lasting effects are achieved by some sequences, whereas no anti-kindling is observed for other sequences. Increasing the stimulation intensity to K = 0.45 improves the robustness of FS against the choice of the sequence used and the initial network conditions (Figure 6B). For K = 0.45 the average synaptic weight stabilizes at a small to intermediate value, depending on the sequence and the initial network conditions. The stabilization of Cav is more rapidly achieved at higher stimulation intensity K.


Augmented brain function by coordinated reset stimulation with slowly varying sequences.

Zeitler M, Tass PA - Front Syst Neurosci (2015)

Effect of switching the sequence during CR stimulation. In a series of simulations with different stimulation intensities (K = 0.20 in left panels and K = 0.45 in right panels) the sequence was either kept fixed [FS CR stimulation, (A,B)], randomly varied just once [in the middle of the stimulation period, at t = 32 s, (C,D)] or randomly varied at three equidistant times [at t = 16, 32, 48 s, (E,F)]. Simulations were performed for eleven different sequence orders and initial network conditions. Each panel shows the dynamics of Cav for each of the eleven simulations in a different color. FS CR stimulation (A,B): Time course of Cav for eleven combinations of different initial network conditions and different sequence for SVS-2400, respectively, for K = 0.20 (A) and K = 0.45 (B). Change of sequence in the middle of the stimulation epoch (C,D): Two different sequences, each applied 1200 times in a row. Change of sequence at t = 32 s, with K = 0.20 (C) and K = 0.45 (D). Sequence is changed three times at equidistant times (t =, 16, 32, and 48 s) during the stimulation epoch (E,F): In each simulation four different sequences are applied 600 times in a row, so that after 16 s the next sequence randomly chosen, with K = 0.20 (E) and K = 0.45 (F). The red horizontal bars represent CR-on periods. The vertical dashed-dotted lines indicate a change of sequence. cmax = 1 in all simulations.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4379899&req=5

Figure 6: Effect of switching the sequence during CR stimulation. In a series of simulations with different stimulation intensities (K = 0.20 in left panels and K = 0.45 in right panels) the sequence was either kept fixed [FS CR stimulation, (A,B)], randomly varied just once [in the middle of the stimulation period, at t = 32 s, (C,D)] or randomly varied at three equidistant times [at t = 16, 32, 48 s, (E,F)]. Simulations were performed for eleven different sequence orders and initial network conditions. Each panel shows the dynamics of Cav for each of the eleven simulations in a different color. FS CR stimulation (A,B): Time course of Cav for eleven combinations of different initial network conditions and different sequence for SVS-2400, respectively, for K = 0.20 (A) and K = 0.45 (B). Change of sequence in the middle of the stimulation epoch (C,D): Two different sequences, each applied 1200 times in a row. Change of sequence at t = 32 s, with K = 0.20 (C) and K = 0.45 (D). Sequence is changed three times at equidistant times (t =, 16, 32, and 48 s) during the stimulation epoch (E,F): In each simulation four different sequences are applied 600 times in a row, so that after 16 s the next sequence randomly chosen, with K = 0.20 (E) and K = 0.45 (F). The red horizontal bars represent CR-on periods. The vertical dashed-dotted lines indicate a change of sequence. cmax = 1 in all simulations.
Mentions: We analyzed the effect of FS CR stimulation for eleven different initial network conditions in combination with a different sequence for each network, respectively. Figure 6A clearly shows that for the FS CR stimulation (SVS-2400) with K = 0.20, the decrease of Cav strongly depends on which sequence is used. Pronounced long-lasting effects are achieved by some sequences, whereas no anti-kindling is observed for other sequences. Increasing the stimulation intensity to K = 0.45 improves the robustness of FS against the choice of the sequence used and the initial network conditions (Figure 6B). For K = 0.45 the average synaptic weight stabilizes at a small to intermediate value, depending on the sequence and the initial network conditions. The stabilization of Cav is more rapidly achieved at higher stimulation intensity K.

Bottom Line: So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS).In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR.To this end, a sequence is applied many times before randomly switching to the next sequence.

View Article: PubMed Central - PubMed

Affiliation: Research Center Jülich, Institute of Neuroscience and Medicine, Neuromodulation (INM-7) Jülich, Germany.

ABSTRACT
Several brain disorders are characterized by abnormally strong neuronal synchrony. Coordinated Reset (CR) stimulation was developed to selectively counteract abnormal neuronal synchrony by desynchronization. For this, phase resetting stimuli are delivered to different subpopulations in a timely coordinated way. In neural networks with spike timing-dependent plasticity CR stimulation may eventually lead to an anti-kindling, i.e., an unlearning of abnormal synaptic connectivity and abnormal synchrony. The spatiotemporal sequence by which all stimulation sites are stimulated exactly once is called the stimulation site sequence, or briefly sequence. So far, in simulations, pre-clinical and clinical applications CR was applied either with fixed sequences or rapidly varying sequences (RVS). In this computational study we show that appropriate repetition of the sequence with occasional random switching to the next sequence may significantly improve the anti-kindling effect of CR. To this end, a sequence is applied many times before randomly switching to the next sequence. This new method is called SVS CR stimulation, i.e., CR with slowly varying sequences. In a neuronal network with strong short-range excitatory and weak long-range inhibitory dynamic couplings SVS CR stimulation turns out to be superior to CR stimulation with fixed sequences or RVS.

No MeSH data available.


Related in: MedlinePlus