Activation of existing memories in anterograde amnesia.

Two principal arguments against a consolidation-block formulation of anterograde amnesia are the existence of pnor-list intrusion errors and the facilitating effect of cued recall Both of these findings can be explained if one assumes an additional process trace activation of already existing memories. This consolidation-block plus trace-activation view predicts that in densely amnesic patients, learning of new items or relationships is almost impossible to demonstrate and cued recall facilitates performance only on already familiar material We test for trace activation by comparing the performance of six dense anterograde amnesia patients with control subjects on three tasks arbitrary word-paired associates (e.g., late-man), recall of disyllabic words cued with the first syllable (e.g., per-son), and recall of disyllabic pseudowords cued with the first syllable (e.g., com-da). As predicted, amnesic patients showed substantial cued-recall effects for real words and not for pseudowords or arbitrarily paired associates The effect of the cuemg on real words was demonstrated to decay over approximately 120 mm, providing some estimate of the time course of trace activation