  We use a biophysical model of a local neuronal circuit to study the
implications of synaptic plasticity for the detection of weak sensory stimuli.
Networks with fast plastic coupling show behavior consistent with stochastic
resonance. Addition of an additional slow coupling that accounts for the
asynchronous release of neurotransmitter results in qualitatively different
properties of signal detection, and also leads to the appearance of transient
post-stimulus bistability. Our results suggest testable hypothesis with regard
to the self-organization and dynamics of local neuronal circuits.
