Figure 1

Detrended fluctuation analysis of the network activity shows the relationship of scaling regimes to constraints on plasticity of the network. Sparsely constrained networks are dominated by high frequency scaling whereas in dense networks the activity is correlated on a wider range of time-scales. Hurst exponents fitted to the data are: 100% connectivity: high-freq=1.1, low-freq=0.7; 40% connectivity: high-freq=1.3, low-freq=0.6. The neurons have a characteristic frequency at ~20 Hz.