We should stress that our findings do not automatically discount the internal orienting hypothesis. As noted, the DMN is not only active during mental imagery, but during various other internally-oriented tasks, including self-referential processing [29], envisioning the future [27], and thinking about another person's perspective [37]. In this respect, it is conceivable that, in the current study, the DMN was not only active during goal-directed internal operations that are relevant for mental imagery and the encoding of internal events, but also during spontaneous internal processes that are intrusive and not relevant to the task at hand. In other words, the fact that more DMN activity is also detrimental to encoding of internal events might be because, activity for task-irrelevant internal processes outweighs the activity for task-relevant internal processes, leading to less rather than more overall activity during successful Int-Enc. Yet, as discussed below, there is an alternative attentional account that can provide a better description of our results.
