There is attenuation of high frequencies of electrical signals propagating in the brain. 
In certain windows 1/f behavior is observed. I review models to explain such 1/f behavior. 
In particular, I address the question if 1/f behavior is due to self-organized criticality 
(sand-pile model). Moreover, I will present recent results from multi-compartment models 
for membrane potentials of neurons from the thalamo-cortex.