Interaction of Working Memory Load and ResponseCompeting Distraction

Interaction of Working Memory Load and Response-Competing Distraction Todd Kelley & Nilli Lavie

Rationale • Previous work has shown that working memory (WM) load increases neural activity related to task-irrelevant faces (De Fockert et al. , 2001) in face-selective areas (e. g. FFA). • Proposed study: examine whether this modulation by WM load occur early (retinotopic cortex including V 1) or (and) late (areas that relate to response competition, e. g. parietal cortex). • Use response-competition (flanker) paradigm involving object categorization.

Stimuli and Design • WM task: digit recall and matching • – Low Load: hold 1 digit in memory – High Load: hold 6 digits in memory Categorization task: fruit or household object – Flanker appears to left or right of target item on %50 of trials • Trial Layout: 264197 + 1 s 2 s + 200 ms 1800 ms 4 0 -2 s 3 s

Data Collection & Analysis • 20 adult subjects (m/f, ages 18 -55) • 4 WML scans; 2 scans per load condition; Scan length: 480 s. – 12 s of fixation at beginning and end of each scan – 9. 5 s per trial (trials last 8 -10 s; ITI = 0. 5) – 48 trials/block • 2 -3 meridian mapping scans; 2 LOC localizer scans • Full brain coverage; TR = 3 s; TE = 50 ms; 3 mm cubic voxels • Interaction of WM load (high-low) and distractor (presentabsent, including retinotopy) • Interaction of WM load (high-low) and response competition (incongruent -congruent distractor conditions)