Since the publication of the previous volume on the prefrontal cortex: its structures, function and pathology in Progress in Brain Research some ten years ago, new data has emerged on the prefrontal cortex and its connections and interactions with structures involved in emotional, motivational and autonomic responses. Cognition, memory and decision making appear to be influenced by emotional and autonomic responses from viscera and the internal state of the organism (e.g. 'gut feelings') induced by the outside world. This resulted in a renewed interest in the interactions of circuits involved in cognition, memory and decision making with those involved in emotional and motivational responses. Therefore, the 21st International Summer School of Brain Research, held in Amsterdam, 23-27 August 1999, was entirely devoted to the question to which extent the prefrontal cortex and related limbic structures function as an integrative center for these interactions.