The Anatomy of a Memory Modulatory System: From Periphery to Brain
Mark G. Packard Cedric L. Williams Larry Cahill James L. McGaugh University of California, Irvine
The fixing of an impression depends upon a physiological process. It takes time for an impression to become so fixed that it can be produced after a long interval; for it to become part of the permanent store of memory considerable time may be necessary.
-- Bumham ( 1903, p. 392)
The hypothesis that the storage of memory involves a physiological timedependent "consolidation" process ( Hebb, 1949; Muller & Pilzecker, 1900) is supported by considerable evidence from studies examining the effects of posttraining treatments on memory. Posttraining treatments including electrical brain stimulation and administration of various drugs and hormones are effective when administered shortly following a training experience, but lose their effectiveness as the training-treatment interval is increased (cf. Gold & MacGaugh, 1975; McGaugh, 1966, 1973, 1989b). Thus, the effects on retention performance produced by immediate posttraining treatments cannot be attributed to proactive influences on sensory, motivational, or motoric processes at the time of the retention test ( McGaugh, 1989a). The posttraining treatment paradigm clearly provides a stringent criterion for demonstrating an effect of a given treatment on memory storage processes, and the use of this paradigm in experimental investigations has contributed significantly to our understanding of the neurobiological bases of memory.
In this chapter, we examine the hypothesis that peripheral hormonal systems and specific brain systems serve to modulate the storage of re-