Structure and function of declarative and nondeclarative memory systems

Structure and function of declarative and nondeclarative memory systems

Larry R. Squire* and
Stuart M. Zola

Veterans Affairs Medical Center, and Departments of Psychiatry and Neurosciences, University of California, San Diego, La Jolla, CA 92161

Abstract

This article reviews recent studies of memory systems in humans and nonhuman primates. Three major conclusions from recent work are that (i) the capacity for nondeclarative (nonconscious) learning can now be studied in a broad array of tasks that assess classification learning, perceptuomotor skill learning, artificial grammar learning, and prototype abstraction; (ii) cortical areas adjacent to the hippocampal formation, including entorhinal, perirhinal, and parahippocampal cortices, are an essential part of the medial temporal lobe memory system that supports 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 retrograde amnesia covering as much as 25 years.

Footnotes

↵ * To whom reprint requests should be addressed at: Veterans Affairs Medical Center (ll6A), 3350 La Jolla Village Drive, San Diego, CA 92161. e-mail: LSquire{at}UCSD.edu.
This paper was presented at a colloquium entitled “Memory: Recording Experience in Cells and Circuits,” organized by Patricia S. Goldman-Rakic, held February 17–20, 1996, at the National Academy of Sciences in Irvine, CA.
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