Neural Networks in three dimensions producing 1/f spectra

We have studied 1/f spectra in the human EEG(electroencephalogram), which are considered to be the characteristics of the self-organizing phenomena. In this paper we obtain 1/f spectra for neural network models: simplified models of the brain. In practice, we employ the coarse-graining method to a neural network model and obtain a 1/f spectrum. Furthermore we carry out computer simulations with neural network models in 3dimensional spaces. Each models has 1/f spectra characteristics that agree with our theory. At the same time, the simulation results have left some future problems.