Abstract
When confronted with an unwelcome reminder of a past event, people often attempt to prevent the event from coming to mind. Previ- ous research has shown that repeatedly preventing retrieval of an unwanted memory leads to forgetting of the avoided memory item (Anderson & Green, Nature, 2001). Neuroimaging evidence implicates extensive, bilateral aspects of lateral prefrontal cortex in mediating such memory suppression (Anderson et al., Science, 2004; Depue et al., Sci- ence, 2007). However, these studies did not examine the exact mecha- nism supported by different prefrontal subregions. The present
functional magnetic resonance imaging study employed a between-sub- ject design to elucidate the neural correlates of two potential mecha- nisms: ‘thought substitution’ (i.e., retrieving an alternative thought to distract from the unwanted memory) and ‘direct suppression’ of the unwanted item. Though both mechanisms led to forgetting of the sup- pressed items compared to a baseline condition, they were supported by partly separable prefrontal subregions. The results thus suggest that vol- untary memory suppression can be mediated by two distinct neuro-cog- nitive mechanisms.
