Poster B69, Sunday, March 25, 8:00-10:00 am, Exhibit Hall C
Prestimulus subsequent memory effects differ as a result of informative or uninformative cues
Eleanor Liu1,2, Paul F Hill1,2, Marianne de Chastelaine1,2, Michael D Rugg1,2; 1University of Texas at Dallas, 2Center for Vital Longevity
Neural activity elicited by a pre-stimulus cue that signals the task to perform on an upcoming stimulus event is predictive of subsequent event memory. Such ‘pre-stimulus subsequent memory effects’ (PSMEs) are found in, among other regions, the medial temporal lobe, especially in the hippocampus, as well as in regions comprising the default mode network. Here we contrasted PSMEs according to whether the pre-stimulus cue was informative (signaling the nature of the upcoming task) or uninformative (task neutral). In two separate experiments, participants made one of two study judgments – animacy or syllabic– on visually presented words. Experiment 1 used the informative cue whereas experiment 2 used the uninformative cue. In both cases the subsequent memory task comprised a recognition memory test incorporating ‘Remember/Know/New’ judgments. PSMEs were operationalized by a ‘Remember’ versus ‘Know’ contrast. A 2x2 full factorial analysis revealed a significant main effect of task type in bilateral parahippocampal cortex, which was driven by greater PSMEs for the animacy compared to the syllable tasks. Parahippocampal PSMEs were more robust in response to informative than uninformative cues. We also observed a cue by task interaction in the right anterior hippocampus, which was driven by informative cues signaling the animacy task (as reported previously for experiment 1). This effect partially overlapped with the parahippocampal PSMEs. These results suggest that hippocampal PSMEs are dependent on task informative cue and may reflect the anticipation of the nature of an upcoming task.
Topic Area: LONG-TERM MEMORY: Episodic