We examine cellular and synaptic properties in neuronal networks using the lamprey spinal cord locomotor network as a model system. While this network is claimed, and often cited, as being characterised, there are actually significant gaps in our understanding of the network, and in the claimed experimental data (see Parker 2006, 2010). We combine various approaches to examine: How short-term activity-dependent synaptic plasticity influences network outputs. Network cellular and synaptic variability . Interactions between activity-dependent and modulatory plasticity (?metaplasticity? and ?metamodulation?). A major focus is on recovery after spinal cord lesions. Lower vertebrates recover function after complete spinal lesions. While this is thought to reflect regeneration across lesion sites, there are also changes in networks above and below lesion sites, in sensory feedback, and in neuromodulator-evoked plasticity. We are investigating how these effects influence recovery.