Examining Motivational Influences on Cognitive Control and Memory

This project seeks to expand on a recent finding that cognitive control influences memory encoding (memory is better for stimuli encountered on conflict versus non-conflict trials in a cognitive control task; Krebs et al., 2015) by investigating the effect of approach versus avoidance motivation on this relationship. Motivation may have varying influences on cognitive processes depending on the type of motivational valence (i.e., reward approach versus punishment avoidance). Reward versus punishment motivation effects on cognitive performance have been associated with activity in different brain regions, but these effects typically are studied on control or memory in isolation. The effect of motivation on the relationship between cognitive control and memory encoding is currently unclear. To approach this problem, this study employs functional magnetic resonance imaging (fMRI) during performance of a behavioral task which requires participants to resolve cognitive conflict under differing motivational contexts and a follow up memory test for task stimuli. The modulation of performance on conflict tasks and subsequent memory tasks is examined in terms of activity in the brain regions of interest. fMRI findings from this study will be used in a follow-up study to target brain regions with transcranial magnetic stimulation (TMS), prior to task performance, to confirm their role in the observed differences. Preliminary analysis of the behavioral data from our first fifty participants shows that induced approach motivation decreases response time without damaging the accuracy of responses, while also improving next-day memory of stimuli. These results fit predictions based on the hypothesized mechanism of increased activation of the hippocampus via dopaminergic projections from the prefrontal cortex in potentially rewarding situations.