STRUCTURE AND FUNCTION OF DECLARATIVE AND NONDECLARATIVE MEMORY-SYSTEMS

This article reviews recent studies of memory systems in humans and no nhuman primates. Three major conclusions from recent work are that (i) the capacity for nondeclarative (nonconscious) learning can now be st udied in a broad array of tasks that assess classification learning, p erceptuomotor skill learning, artificial grammar learning, and prototy pe abstraction; (ii) cortical areas adjacent to the hippocampal format ion, including entorhinal, perirhinal, and parahippocampal cortices, a re an essential part of the medial temporal lobe memory system that su pports declarative (conscious) memory; and (iii) in humans, bilateral damage limited to the hippocampal formation is nevertheless sufficient to produce severe anterograde amnesia and temporally graded retrograd e amnesia covering as much as 25 years.