The functional role of neural activity preceding memory formation Leun Otten & Matthias Gruber BUCNI project presentation 19 Feb 2009 Part of BBSRC project grant application Aim: to understand the neural correlates of anticipatory processes in encoding MEG and fMRI

Background Neural activity elicited by an event can index its successful encoding into memory Recently, shown that encoding is also influenced by activity before an event Important for several reasons Largely unknown what brain regions underlie encoding-related pre-stimulus activity EEG work suggests role for semantic preparation Event Time

Current study Aim: to assess which brain regions show activity that precedes memory formation in semantic and non-semantic study tasks Design: Study phase: Incidental study phase Recognition memory test Delay (~20 min) In scanner Outside scanner Time TABLE CAT ROSE o x o -120 words in living/non-living and alphabetic/non-alphabetic study tasks -120 null events -Cue-word and inter-trial intervals optimized to allow maximum separation of activity before and after word onset

fMRI methods Rapid event-related fMRI sequence Whole-head scanning Two sessions of about 25 min each plus structural 16 subjects with acceptable memory performance (twenty 1.5-hour slots) SPM, modeling pre- and post-stimulus activity simultaneously, random effects analyses Scanning Basic contrast is between study items that are later remembered vs. forgotten (subsequent memory effects) Which regions show pre-stimulus subsequent memory effects in the semantic study task? LIFG, MTL, PPC, midbrain? Do these regions overlap with those differentiating semantic vs. non-semantic preparation? Which regions (if any) show pre-stimulus effects in the non-semantic study task? Is there overlap between the regions demonstrating pre- and post-stimulus effects? Does pre-stimulus activity predict an individuals overall memory performance? Questions/contrasts of interest