Several major changes in activity patterns in the basal ganglia are associated with parkinsonism. These include enhanced bursting, changes in power and frequency of oscillations in firing, and increased correlation in neuronal activity. In this talk, I will focus in part on computational analysis of effects that these changes may induce in downstream basal ganglia and thalamic areas, which may lead to parkinsonian motor signs. These ideas provide a framework for understanding the mechanisms underlying the therapeutic efficacy of deep brain stimulation (DBS), and I will also discuss how the impact of DBS on bursting and synaptic transfer could contribute to this efficacy.