Most studies of vertebrate spinal motoneurones have suggested that they possess relatively simple membrane properties, causing them to behave merely as passively driven output neurones in motor behaviour. According to this concept, motoneurones passively transform the net synaptic drive from pre-motoneuronal levels into spike trains. Recent research has demonstrated a more complex picture by showing that motoneurones can express nonlinear intrinsic response properties, such as plateau potentials and endogenous oscillatory properties. This work suggests that the 'final common pathway' is actively involved in shaping motor behaviour.