This volume represents the collected papers presented at the Third Triennial Symposium of the International Basal Ganglia society (IBAGS) held at Capo Boi, Italy, June 10-13, 1989. About 300 members of the society and participants attended the symposium which was held in a delightful environment conducive to the formal and informal exchange of scientific thought. The interdisciplinary nature of the symposium was unique in its coverage of the neurosciences from molecular biology to clinical and behavioural studies. The 80 papers collected here reflect the wide spectrum and the depth of studies...