The prefrontal cortex is particularly challenging as it has undergone great expansion during phylogenetic development and because it plays a crucial role in regulating most complex behaviors. Progress in research techniques in animals, and in the development of non-invasive brain imaging approaches in humans, have precipitated a resurgence of interest in the prefrontal cortex. To shed light on the rapidly accumulated information on motor and cognitive functions of the prefrontal cortex the Fondation IPSEN organized a Symposium (third in the series of the Colloques Medecine et Recherche) held in Paris on November 24, 1992. This volume contains the proceedings of this meeting with interdisciplinary contributions from such fields as neuroanatomy, neuropharmacology, electrophysiology as well as from clinical and behavior studies. The fourth meeting in the series will be held on October 11, 1993, and is to be entitled "Temporal coding: an area of renewed interest in brain function" (Organizing committee: G. Buzsaki, New York; W. Singer, Frankfurt; R. Llinas, New York; A. Berthoz, Paris; Y. Christen, Paris). Paris, France Anne-Marie Thierry September 1993 Yves Christen Contents How to Study Frontal Lobe Functions in Humans B. Dubois, M. Verin, C. Teixeira-Ferreira, A. Sirigu, and B. Pillon . . 1 Distinctive Chemoanatomical and Developmental Features of the Prefrontal Dopaminergic System in Primates as Compared to Rodents B. Berger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 . . . . . . . . . . . . . . . .