This volume, the sixth in the IBAGS series, summarizes major contributions in clinical and basic research on the basal ganglia. The sixth meeting of the Society was held on Cape Cod, in the state of Massachusetts, USA, in October, 1998. Altogether 16 countries were represented by 227 participants. This volume contains papers contributed by participants. The focus of the sixth triennial IBAGS meeting, and of this volume, was to bring to- gether leaders in basic and clinical science to address two sets of still-persisting questions in the field. The first set focuses on the functions of the...