The time locked theta response reflects interindividual differences in human memory performance

Recent research indicates that an increase in theta band power is related to episodic memory performance. In this study with human subjects, the evoked (time locked) and induced (not time locked) theta response is analyzed in a recognition task. The results show a strong evoked theta response during an early retrieval period of up to 400 ms. Only for good memory performers theta is strictly time locked, indicating that theta peaks appear in preferred time windows after a target is presented. This effect - which coincides with a large P3 - suggests that good performance requires a strict timing of different processing stages that correspond to cycles of theta activity. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.