In animal models of chronic injury, however, motoneuronal PICs return (Li and Bennett 2003; Li et al. 2004a), restoring the ability of motoneurons to produce sustained output in response to synaptic input. The return of motoneuronal PICs, which allows motoneurons to fully recover their ability to produce sustained output in response to synaptic input, coincides with the appearance of spasticity (Li et al. 2004b). In addition, blocking these PICs and long-lasting plateau potentials inhibits spastic behavior (Bennett et al. 2001a; Li et al. 2004a). To summarize, in the animal model of the chronic SCI condition, motoneurons demonstrate remarkable recovery of PICs, which likely play a major role in transmitting synaptic reflex inputs that generate spasticity.