Electrophysiological studies of identifying and modulating the preparatory strategic processes involved in episodic memory retrieval

Abstract

Successful retrieval of episodic memories has been shown to depend on the overlap between the processes engaged during encoding and those re-engaged during retrieval. The ability to strategically adapt cue processing to maximize this overlap, sometimes referred to as “retrieval orientation”, has been supported by numerous studies employing electroencephalography (EEG), which demonstrate differences according to the class of memories being sought. However, research in this domain has largely focused on event-related potential (ERP) effects of sustained amplitude that occur after the onset of retrieval cues, thereby failing to indicate whether such effects might be engaged in a preparatory manner before cue onset. Here, we describe two experiments that addressed this issue by employing an analysis approach focusing on the pre-stimulus period of retrieval test trials and capitalizing on the increased sensitivity of multivariate pattern analysis (MVPA) of oscillatory activity. Experiment 1 established evidence of a preparatory form of retrieval orienting and examined the potential fluctuation versus stability of such processing. Experiment 2 attempted to directly modulate the engagement of orienting processes by parametrically manipulating the extent to which responses during the retrieval task are speeded. By novelly quantifying the relationship between multivariate neural correlates of retrieval orientation and behavioral measures of performance, and testing how orienting might be flexibly adjusted to meet task demands, the current project serves as a starting point for developing techniques aimed at improving episodic memory retrieval through strategic control.