  Avalanches with power-law distributed size parameters have been observed in
neuronal networks. This observation might be a manifestation of the
self-organized criticality (SOC). Yet, the physiological mechanicsm of this
behavior is currently unknown. Describing synaptic noise as transmission
failures mainly originating from the probabilistic nature of neurotransmitter
release, this study investigates the potential of this noise as a mechanism for
driving the functional architecture of the neuronal networks towards SOC. To
this end, a simple finite state neuron model, with activity dependent and
synapse specific failure probabilities, was built based on the known anatomical
connectivity data of the nematode Ceanorhabditis elegans. Beginning from random
values, it was observed that synaptic noise levels picked out a set of synapses
and consequently an active subnetwork which generates power-law distributed
neuronal avalanches. The findings of this study brings up the possibility that
synaptic failures might be a component of physiological processes underlying
SOC in neuronal networks.
