Limits...
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

Comparison of the anti-kindling effects for some numbers of different sequences applied during the SVS CR stimulation. (A) Boxplots of Cav at t = 128 s for different numbers of sequence changes used in the SVS CR stimulation with K = 0.20. (B) Boxplots of Rav at t = 128 s for some numbers of different sequences used in the SVS CR stimulation with K = 0.20. (C) As in (A) for K = 0.45. (D) As in (B) for K = 0.45. The black lines within the boxes show the medians for each condition, the boxes the middle 50% and the whiskers below (above) the boxes the first (last, respectively) 25%. Outliers are defined as 1.5 times the length of the box below or above the box and represented by open circles. For each condition (K-value and number of sequences) the simulations are repeated eleven times for different initial conditions of the network in combination with different sequence(s). The number of consecutive sequence repetitions was adjusted with respect to the number of different sequences so that the duration of the CR-on period is always 64 s for each simulation. For example if two different sequences are used, each of them is repeated 1200 times in a row, in case four different sequences are used, each of them is repeated 600 times.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4379899&req=5

Figure 7: Comparison of the anti-kindling effects for some numbers of different sequences applied during the SVS CR stimulation. (A) Boxplots of Cav at t = 128 s for different numbers of sequence changes used in the SVS CR stimulation with K = 0.20. (B) Boxplots of Rav at t = 128 s for some numbers of different sequences used in the SVS CR stimulation with K = 0.20. (C) As in (A) for K = 0.45. (D) As in (B) for K = 0.45. The black lines within the boxes show the medians for each condition, the boxes the middle 50% and the whiskers below (above) the boxes the first (last, respectively) 25%. Outliers are defined as 1.5 times the length of the box below or above the box and represented by open circles. For each condition (K-value and number of sequences) the simulations are repeated eleven times for different initial conditions of the network in combination with different sequence(s). The number of consecutive sequence repetitions was adjusted with respect to the number of different sequences so that the duration of the CR-on period is always 64 s for each simulation. For example if two different sequences are used, each of them is repeated 1200 times in a row, in case four different sequences are used, each of them is repeated 600 times.

Mentions: Analogously, we further increase the number of different sequences used during one CR epoch. Figure 7 shows the stimulation outcome in terms of synaptic connectivity Cav (Figures 7A,C) and order parameter Rav (Figures 7B,D) averaged over the last 1.6 s of the CR-off period for different stimulation intensities (K = 0.20 in Figures 7A,B and K = 0.45 in Figures 7C,D). The statistics obtained from a set of eleven simulations performed for different initial network conditions and sequence orders shows that the main part of the SVS-induced improvement of the CR effect is already achieved with four different sequences. Using more than four different sequences hardly leads to a further reduction of Rav and Cav and their variability.


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

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

Comparison of the anti-kindling effects for some numbers of different sequences applied during the SVS CR stimulation. (A) Boxplots of Cav at t = 128 s for different numbers of sequence changes used in the SVS CR stimulation with K = 0.20. (B) Boxplots of Rav at t = 128 s for some numbers of different sequences used in the SVS CR stimulation with K = 0.20. (C) As in (A) for K = 0.45. (D) As in (B) for K = 0.45. The black lines within the boxes show the medians for each condition, the boxes the middle 50% and the whiskers below (above) the boxes the first (last, respectively) 25%. Outliers are defined as 1.5 times the length of the box below or above the box and represented by open circles. For each condition (K-value and number of sequences) the simulations are repeated eleven times for different initial conditions of the network in combination with different sequence(s). The number of consecutive sequence repetitions was adjusted with respect to the number of different sequences so that the duration of the CR-on period is always 64 s for each simulation. For example if two different sequences are used, each of them is repeated 1200 times in a row, in case four different sequences are used, each of them is repeated 600 times.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4379899&req=5

Figure 7: Comparison of the anti-kindling effects for some numbers of different sequences applied during the SVS CR stimulation. (A) Boxplots of Cav at t = 128 s for different numbers of sequence changes used in the SVS CR stimulation with K = 0.20. (B) Boxplots of Rav at t = 128 s for some numbers of different sequences used in the SVS CR stimulation with K = 0.20. (C) As in (A) for K = 0.45. (D) As in (B) for K = 0.45. The black lines within the boxes show the medians for each condition, the boxes the middle 50% and the whiskers below (above) the boxes the first (last, respectively) 25%. Outliers are defined as 1.5 times the length of the box below or above the box and represented by open circles. For each condition (K-value and number of sequences) the simulations are repeated eleven times for different initial conditions of the network in combination with different sequence(s). The number of consecutive sequence repetitions was adjusted with respect to the number of different sequences so that the duration of the CR-on period is always 64 s for each simulation. For example if two different sequences are used, each of them is repeated 1200 times in a row, in case four different sequences are used, each of them is repeated 600 times.
Mentions: Analogously, we further increase the number of different sequences used during one CR epoch. Figure 7 shows the stimulation outcome in terms of synaptic connectivity Cav (Figures 7A,C) and order parameter Rav (Figures 7B,D) averaged over the last 1.6 s of the CR-off period for different stimulation intensities (K = 0.20 in Figures 7A,B and K = 0.45 in Figures 7C,D). The statistics obtained from a set of eleven simulations performed for different initial network conditions and sequence orders shows that the main part of the SVS-induced improvement of the CR effect is already achieved with four different sequences. Using more than four different sequences hardly leads to a further reduction of Rav and Cav and their variability.

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