Gating and habituation deficits have been identified as major features of the schizophrenias. When gating and habituation functions are impaired, the schizophrenia patient can neither efficiently screen out trivial, distracting stimuli nor effectively attend to and process salient stimuli in the environment. Along with the clinical significance and symptom correlates of gating and habituation deficits in schizophrenia, studies of these functions have produced much important data. Specifically, such studies have demonstrated the involvement of structures in the cortico-striato-pallido-pontine (CSPP) neural circuitry in both schizophrenia and the normal processing of information. Thus, neurobiological manipulations along various axes of the CSPP can allow investigators to understand the neural basis of impaired gating and habituation in the schizophrenias.