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Irregular spiking of pyramidal neurons organizes as scale-invariant neuronal avalanches in the awake state.

Bellay T, Klaus A, Seshadri S, Plenz D - Elife (2015)

Bottom Line: As the animal transitions from the anesthetized to awake state, spontaneous single neuron firing increases in irregularity and assembles into scale-invariant avalanches at the group level.In vitro spike avalanches emerged naturally yet required balanced excitation and inhibition.This demonstrates that neuronal avalanches are linked to the global physiological state of wakefulness and that cortical resting activity organizes as avalanches from firing of local PN groups to global population activity.

View Article: PubMed Central - PubMed

Affiliation: Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States.

ABSTRACT
Spontaneous fluctuations in neuronal activity emerge at many spatial and temporal scales in cortex. Population measures found these fluctuations to organize as scale-invariant neuronal avalanches, suggesting cortical dynamics to be critical. Macroscopic dynamics, though, depend on physiological states and are ambiguous as to their cellular composition, spatiotemporal origin, and contributions from synaptic input or action potential (AP) output. Here, we study spontaneous firing in pyramidal neurons (PNs) from rat superficial cortical layers in vivo and in vitro using 2-photon imaging. As the animal transitions from the anesthetized to awake state, spontaneous single neuron firing increases in irregularity and assembles into scale-invariant avalanches at the group level. In vitro spike avalanches emerged naturally yet required balanced excitation and inhibition. This demonstrates that neuronal avalanches are linked to the global physiological state of wakefulness and that cortical resting activity organizes as avalanches from firing of local PN groups to global population activity.

No MeSH data available.


Related in: MedlinePlus

Scaling relationship between lifetime and size of spontaneous AP clusters supports neuronal avalanche dynamics (Sethna et al., 2001; Friedman et al., 2012).(A) Double logarithmic plot of avalanche duration and corresponding avalanche size for one local L2/3 PN group in vivo in the AW state. Duration and size scale according to a power law with exponent 1/c. In this example, c was found to be 0.75 based on regression analysis (red line). (B) For increasing temporal resolution, the scaling relationship between life time exponent and size exponent approaches c.DOI:http://dx.doi.org/10.7554/eLife.07224.013
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fig6s1: Scaling relationship between lifetime and size of spontaneous AP clusters supports neuronal avalanche dynamics (Sethna et al., 2001; Friedman et al., 2012).(A) Double logarithmic plot of avalanche duration and corresponding avalanche size for one local L2/3 PN group in vivo in the AW state. Duration and size scale according to a power law with exponent 1/c. In this example, c was found to be 0.75 based on regression analysis (red line). (B) For increasing temporal resolution, the scaling relationship between life time exponent and size exponent approaches c.DOI:http://dx.doi.org/10.7554/eLife.07224.013

Mentions: An alternative approach to obtain avalanches, in which periods of integrated population activity above a population threshold were extracted (Poil et al., 2012), also yielded power-law size distributions with exponent close to −1.5 and cut-off that were robust to changes in λthr (Figure 6A–D). Similar to what was found when using the original definition of avalanches, cluster size distributions obtained by population thresholding deviated from avalanche dynamics under isoflurane anesthesia (Figure 5B, Figure 6E, p < 0.01; Kruskal–Wallis test on Kolmogorov–Smirnov distances, DKS). Furthermore, cluster size and lifetime were correlated, and the corresponding exponent scaled as suggested by the theory of critical systems (Sethna et al., 2001) (Figure 6—figure supplement 1).10.7554/eLife.07224.012Figure 6.Identifying avalanche dynamics, that is, power law in clustering, using thresholding of the population rate vector (Poil et al., 2012).


Irregular spiking of pyramidal neurons organizes as scale-invariant neuronal avalanches in the awake state.

Bellay T, Klaus A, Seshadri S, Plenz D - Elife (2015)

Scaling relationship between lifetime and size of spontaneous AP clusters supports neuronal avalanche dynamics (Sethna et al., 2001; Friedman et al., 2012).(A) Double logarithmic plot of avalanche duration and corresponding avalanche size for one local L2/3 PN group in vivo in the AW state. Duration and size scale according to a power law with exponent 1/c. In this example, c was found to be 0.75 based on regression analysis (red line). (B) For increasing temporal resolution, the scaling relationship between life time exponent and size exponent approaches c.DOI:http://dx.doi.org/10.7554/eLife.07224.013
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492006&req=5

fig6s1: Scaling relationship between lifetime and size of spontaneous AP clusters supports neuronal avalanche dynamics (Sethna et al., 2001; Friedman et al., 2012).(A) Double logarithmic plot of avalanche duration and corresponding avalanche size for one local L2/3 PN group in vivo in the AW state. Duration and size scale according to a power law with exponent 1/c. In this example, c was found to be 0.75 based on regression analysis (red line). (B) For increasing temporal resolution, the scaling relationship between life time exponent and size exponent approaches c.DOI:http://dx.doi.org/10.7554/eLife.07224.013
Mentions: An alternative approach to obtain avalanches, in which periods of integrated population activity above a population threshold were extracted (Poil et al., 2012), also yielded power-law size distributions with exponent close to −1.5 and cut-off that were robust to changes in λthr (Figure 6A–D). Similar to what was found when using the original definition of avalanches, cluster size distributions obtained by population thresholding deviated from avalanche dynamics under isoflurane anesthesia (Figure 5B, Figure 6E, p < 0.01; Kruskal–Wallis test on Kolmogorov–Smirnov distances, DKS). Furthermore, cluster size and lifetime were correlated, and the corresponding exponent scaled as suggested by the theory of critical systems (Sethna et al., 2001) (Figure 6—figure supplement 1).10.7554/eLife.07224.012Figure 6.Identifying avalanche dynamics, that is, power law in clustering, using thresholding of the population rate vector (Poil et al., 2012).

Bottom Line: As the animal transitions from the anesthetized to awake state, spontaneous single neuron firing increases in irregularity and assembles into scale-invariant avalanches at the group level.In vitro spike avalanches emerged naturally yet required balanced excitation and inhibition.This demonstrates that neuronal avalanches are linked to the global physiological state of wakefulness and that cortical resting activity organizes as avalanches from firing of local PN groups to global population activity.

View Article: PubMed Central - PubMed

Affiliation: Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States.

ABSTRACT
Spontaneous fluctuations in neuronal activity emerge at many spatial and temporal scales in cortex. Population measures found these fluctuations to organize as scale-invariant neuronal avalanches, suggesting cortical dynamics to be critical. Macroscopic dynamics, though, depend on physiological states and are ambiguous as to their cellular composition, spatiotemporal origin, and contributions from synaptic input or action potential (AP) output. Here, we study spontaneous firing in pyramidal neurons (PNs) from rat superficial cortical layers in vivo and in vitro using 2-photon imaging. As the animal transitions from the anesthetized to awake state, spontaneous single neuron firing increases in irregularity and assembles into scale-invariant avalanches at the group level. In vitro spike avalanches emerged naturally yet required balanced excitation and inhibition. This demonstrates that neuronal avalanches are linked to the global physiological state of wakefulness and that cortical resting activity organizes as avalanches from firing of local PN groups to global population activity.

No MeSH data available.


Related in: MedlinePlus