Neuroanatomy of Memory

Abstract

Three important developments have occurred in the area of during the past decade. The first was the recognition that there is more than one kind of (Cohen 1984; Schacter 1987; Squire 1982; Tulving 1985). Declarative (or, explicit memory) affords the capacity for con­ scious recollections about facts and events. This is the kind of that is usually referred to when the terms memory or remembering are used in ordinary language. Declarative can be contrasted with nondeclarative (or implicit) memory, a heterogeneous collection of nonconscious abilities that includes the learning of skills and habits, prim­ ing, and some forms of classical conditioning. In these cases, experience cumulates in behavioral change, but without affording access to any content. The distinction between declarative and nondeclarative is fundamental, because it has turned out that different kinds of are supported by different brain systems. The second important development was the establishment of an animal model of human amnesia in the monkey (Mahut & Moss 1984; Mishkin 1982; Squire & Zola-Morgan 1983). In the 1950s, Scoville & Milner (1957) described the severe amnesia that followed bilateral surgical removal of the medial temporal lobe (patient H.M.). This important case demon­ strated that is a distinct cerebral function, dissociable from other perceptual and cognitive abilities. Subsequently, surgical lesions of the medial temporai iobe in monkeys, which approximated the damage sus­ tained by patient H.M., were shown to reproduce many features of human impairment . In particular, both monkeys and humans were