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Temporal correlations in neuronal avalanche occurrence.

Lombardi F, Herrmann HJ, Plenz D, de Arcangelis L - Sci Rep (2016)

Bottom Line: Moreover we evidence that sizes of consecutive avalanches are correlated.In particular, we show that an avalanche tends to be larger or smaller than the following one for short or long time separation, respectively.Our analysis represents the first attempt to provide a quantitative estimate of correlations between activity and quiescence in the framework of neuronal avalanches and will help to enlighten the mechanisms underlying spontaneous activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Computational Physics for Engineering Materials, ETH, Zurich, Switzerland.

ABSTRACT
Ongoing cortical activity consists of sequences of synchronized bursts, named neuronal avalanches, whose size and duration are power law distributed. These features have been observed in a variety of systems and conditions, at all spatial scales, supporting scale invariance, universality and therefore criticality. However, the mechanisms leading to burst triggering, as well as the relationship between bursts and quiescence, are still unclear. The analysis of temporal correlations constitutes a major step towards a deeper understanding of burst dynamics. Here, we investigate the relation between avalanche sizes and quiet times, as well as between sizes of consecutive avalanches recorded in cortex slice cultures. We show that quiet times depend on the size of preceding avalanches and, at the same time, influence the size of the following one. Moreover we evidence that sizes of consecutive avalanches are correlated. In particular, we show that an avalanche tends to be larger or smaller than the following one for short or long time separation, respectively. Our analysis represents the first attempt to provide a quantitative estimate of correlations between activity and quiescence in the framework of neuronal avalanches and will help to enlighten the mechanisms underlying spontaneous activity.

No MeSH data available.


Related in: MedlinePlus

Relation between the quiet time Δti and the size si+1 of the following avalanche.The quantity δP(si+1 < s0, Δti < t0) as a function of s0 for different t0 values and different conditions, non-driven, driven and disinhibited (PTX). Each curve represents an average over all experimental samples in a given condition. The bar on each point is 2σ(si+1 < s0, Δti < t0). (a) Non-driven; (b) Driven; (c) Disinhibited (PTX). Insets: The ratio δP(si+1 < s0, Δti < t0)/σ as a function of s0 for different values of t0; dashed lines delimit the interval (−2, 2). In most cases δP(si+1 < s0, Δti < t0)/σ is much larger than 2. Therefore these results are significant at a level generally lower than 0.05 and give solid evidences of correlations between avalanches and preceding quiet times.
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f5: Relation between the quiet time Δti and the size si+1 of the following avalanche.The quantity δP(si+1 < s0, Δti < t0) as a function of s0 for different t0 values and different conditions, non-driven, driven and disinhibited (PTX). Each curve represents an average over all experimental samples in a given condition. The bar on each point is 2σ(si+1 < s0, Δti < t0). (a) Non-driven; (b) Driven; (c) Disinhibited (PTX). Insets: The ratio δP(si+1 < s0, Δti < t0)/σ as a function of s0 for different values of t0; dashed lines delimit the interval (−2, 2). In most cases δP(si+1 < s0, Δti < t0)/σ is much larger than 2. Therefore these results are significant at a level generally lower than 0.05 and give solid evidences of correlations between avalanches and preceding quiet times.

Mentions: Next we study the relation between the quiet time Δti and the size si+1 of the following avalanche. In this case we analyze the quantity δP(si+1 < s0, Δti < t0), which we show in Fig. 5 as a function of s0 for several values of the threshold t0. Firstly, we discuss the non-driven condition (Fig. 5a) and notice that δP(si+1 < s0, Δti < t0) is always positive and decreases going from t0 = 20 ms to t0 = 4000 ms. When avalanches separated by larger time intervals are progressively included in the analysis, the maximum of δP(si+1 < s0, Δti < t0) consistently shifts towards larger s0 values, suggesting that the longer the quiet time the larger the following avalanche.


Temporal correlations in neuronal avalanche occurrence.

Lombardi F, Herrmann HJ, Plenz D, de Arcangelis L - Sci Rep (2016)

Relation between the quiet time Δti and the size si+1 of the following avalanche.The quantity δP(si+1 < s0, Δti < t0) as a function of s0 for different t0 values and different conditions, non-driven, driven and disinhibited (PTX). Each curve represents an average over all experimental samples in a given condition. The bar on each point is 2σ(si+1 < s0, Δti < t0). (a) Non-driven; (b) Driven; (c) Disinhibited (PTX). Insets: The ratio δP(si+1 < s0, Δti < t0)/σ as a function of s0 for different values of t0; dashed lines delimit the interval (−2, 2). In most cases δP(si+1 < s0, Δti < t0)/σ is much larger than 2. Therefore these results are significant at a level generally lower than 0.05 and give solid evidences of correlations between avalanches and preceding quiet times.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837393&req=5

f5: Relation between the quiet time Δti and the size si+1 of the following avalanche.The quantity δP(si+1 < s0, Δti < t0) as a function of s0 for different t0 values and different conditions, non-driven, driven and disinhibited (PTX). Each curve represents an average over all experimental samples in a given condition. The bar on each point is 2σ(si+1 < s0, Δti < t0). (a) Non-driven; (b) Driven; (c) Disinhibited (PTX). Insets: The ratio δP(si+1 < s0, Δti < t0)/σ as a function of s0 for different values of t0; dashed lines delimit the interval (−2, 2). In most cases δP(si+1 < s0, Δti < t0)/σ is much larger than 2. Therefore these results are significant at a level generally lower than 0.05 and give solid evidences of correlations between avalanches and preceding quiet times.
Mentions: Next we study the relation between the quiet time Δti and the size si+1 of the following avalanche. In this case we analyze the quantity δP(si+1 < s0, Δti < t0), which we show in Fig. 5 as a function of s0 for several values of the threshold t0. Firstly, we discuss the non-driven condition (Fig. 5a) and notice that δP(si+1 < s0, Δti < t0) is always positive and decreases going from t0 = 20 ms to t0 = 4000 ms. When avalanches separated by larger time intervals are progressively included in the analysis, the maximum of δP(si+1 < s0, Δti < t0) consistently shifts towards larger s0 values, suggesting that the longer the quiet time the larger the following avalanche.

Bottom Line: Moreover we evidence that sizes of consecutive avalanches are correlated.In particular, we show that an avalanche tends to be larger or smaller than the following one for short or long time separation, respectively.Our analysis represents the first attempt to provide a quantitative estimate of correlations between activity and quiescence in the framework of neuronal avalanches and will help to enlighten the mechanisms underlying spontaneous activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of Computational Physics for Engineering Materials, ETH, Zurich, Switzerland.

ABSTRACT
Ongoing cortical activity consists of sequences of synchronized bursts, named neuronal avalanches, whose size and duration are power law distributed. These features have been observed in a variety of systems and conditions, at all spatial scales, supporting scale invariance, universality and therefore criticality. However, the mechanisms leading to burst triggering, as well as the relationship between bursts and quiescence, are still unclear. The analysis of temporal correlations constitutes a major step towards a deeper understanding of burst dynamics. Here, we investigate the relation between avalanche sizes and quiet times, as well as between sizes of consecutive avalanches recorded in cortex slice cultures. We show that quiet times depend on the size of preceding avalanches and, at the same time, influence the size of the following one. Moreover we evidence that sizes of consecutive avalanches are correlated. In particular, we show that an avalanche tends to be larger or smaller than the following one for short or long time separation, respectively. Our analysis represents the first attempt to provide a quantitative estimate of correlations between activity and quiescence in the framework of neuronal avalanches and will help to enlighten the mechanisms underlying spontaneous activity.

No MeSH data available.


Related in: MedlinePlus