Limits...
Being critical of criticality in the brain.

Beggs JM, Timme N - Front Physiol (2012)

Bottom Line: The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point.This hypothesis, however, is still controversial.Points and counter points are presented in dialog form.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indiana University Bloomington, IN, USA.

ABSTRACT
Relatively recent work has reported that networks of neurons can produce avalanches of activity whose sizes follow a power law distribution. This suggests that these networks may be operating near a critical point, poised between a phase where activity rapidly dies out and a phase where activity is amplified over time. The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point. This hypothesis, however, is still controversial. Here we will explain the concept of criticality and review the substantial objections to the criticality hypothesis raised by skeptics. Points and counter points are presented in dialog form.

No MeSH data available.


Average dynamic correlation as a function of distance. At high and low temperatures, the average dynamic correlation between two lattice sites decreases rapidly toward 0 as the distance between the lattice sites is increased. At the critical temperature, the average dynamic correlation also decreases toward 0 as the distance is increased, but much more gradually.
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Figure 3: Average dynamic correlation as a function of distance. At high and low temperatures, the average dynamic correlation between two lattice sites decreases rapidly toward 0 as the distance between the lattice sites is increased. At the critical temperature, the average dynamic correlation also decreases toward 0 as the distance is increased, but much more gradually.

Mentions: Critio: Sure. If we were to measure the dynamic correlation between two spin sites i and j as a function of distance, we would find out that it decreases with distance in all cases. Remember that in this model, we have only built in connections between nearest neighbor spins. So you wouldn’t expect the correlation to extend much beyond that, at least when the temperature is very high or very low. But at the critical temperature, we find that the dynamic correlation is above 0 well beyond the nearest neighbor distance. [Critio sketches Figure 3.]


Being critical of criticality in the brain.

Beggs JM, Timme N - Front Physiol (2012)

Average dynamic correlation as a function of distance. At high and low temperatures, the average dynamic correlation between two lattice sites decreases rapidly toward 0 as the distance between the lattice sites is increased. At the critical temperature, the average dynamic correlation also decreases toward 0 as the distance is increased, but much more gradually.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369250&req=5

Figure 3: Average dynamic correlation as a function of distance. At high and low temperatures, the average dynamic correlation between two lattice sites decreases rapidly toward 0 as the distance between the lattice sites is increased. At the critical temperature, the average dynamic correlation also decreases toward 0 as the distance is increased, but much more gradually.
Mentions: Critio: Sure. If we were to measure the dynamic correlation between two spin sites i and j as a function of distance, we would find out that it decreases with distance in all cases. Remember that in this model, we have only built in connections between nearest neighbor spins. So you wouldn’t expect the correlation to extend much beyond that, at least when the temperature is very high or very low. But at the critical temperature, we find that the dynamic correlation is above 0 well beyond the nearest neighbor distance. [Critio sketches Figure 3.]

Bottom Line: The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point.This hypothesis, however, is still controversial.Points and counter points are presented in dialog form.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indiana University Bloomington, IN, USA.

ABSTRACT
Relatively recent work has reported that networks of neurons can produce avalanches of activity whose sizes follow a power law distribution. This suggests that these networks may be operating near a critical point, poised between a phase where activity rapidly dies out and a phase where activity is amplified over time. The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point. This hypothesis, however, is still controversial. Here we will explain the concept of criticality and review the substantial objections to the criticality hypothesis raised by skeptics. Points and counter points are presented in dialog form.

No MeSH data available.