The amazing quantity of information required to initialize the enormou
s number of connections on which is based the neuron network functioni
ng cannot possibly be encoded in the genome. The answer to this puzzli
ng problem could be in self-organized criticality. In order to apply t
his idea we have introduced a refractary period in the famous Bak-Snep
pen model. We also compare our results with real measurements of singl
e neuron activity.