ABSTRACT
One of the fundamental principles of mammalian brain function that has emerged from recent research is that learning and memory processes are not the province of a single neuronal system. Instead, several anatomically discrete systems each mediate the acquisition and/or storage of different classes of learned behaviors (Berger, Berry, & Thompson, 1986; Cohen, 1984; Desmond & Moore, 1982; Disterhoft & Segal, 1978; Gabriel et al., 1980; Gabriel & Sparenborg, 1987; Hirsh, 1974; LeDoux, 1987; Milner, 1970; Mishkin & Petri, 1984; O'Keefe & Nadel, 1975; Olds et al., 1972; Olton, Becker, & Handlemann, 1979; Squire, 1982; Thompson, Berger, & Madden, 1983) One of the most well-characterized examples of such a specialization of learning and memory function is the hippo-campal formation. In humans, the hippocampus and adjacent limbic brain regions are essential for the formation of long-term memories of names and facts (i.e., “data-based” memory; Cohen & Squire, 1980; Zola-Morgan, Squire, & Amaral, 1986). In lower mammals an analogous specialization is expressed in the necessity of the hippocampus for learning higher order associations, or conditional operations (Berger & Orr, 1983; Eichenbaum, Fagan, Mathews, & Cohen, 1988; Fagan & Olton, 1986; Hirsh, 1974, 1980; Loechner & Weisz, 1987; Nadel & Willner, 1980; O'Keefe & Nadel, 1975; Port & Patterson, 1984; Ross et al., 1984.)
