Figure A3.

Long-range correlations. Black circles correspond to brain data and red squares to the results from an exponential interaction model with the same geometry for each cluster. In the exponential case as N grows the average correlation converges, meanwhile for the brain data it continues growing demonstrating the presence of long-range correlations in the data. The black line corresponds to a power law fit y = kx^−0.7. From Equation 21 we obtain an exponent α = 0.9. The inset corresponds to the variance of the mean activity as a function of N.