Recent studies suggest that a brain network mainly associated with episodic memory has a more general function in imagining oneself in another time, place or perspective (e.g. episodic future thought, theory of mind, default mode). If this is true, counterfactual thinking (e.g. 'If I had left the office earlier, I wouldn't have missed my train.') should also activate this network. Present functional magnetic resonance imaging (fMRI) study explores the common and distinct neural activity of counterfactual and episodic thinking by directly comparing the imagining of upward counterfactuals (creating better outcomes for negative past events) with the re-experiencing of negative past events and the imagining of positive future events. Results confirm that episodic and counterfactual thinking share a common brain network, involving a core memory network (hippocampal area, temporal lobes, midline, and lateral parietal lobes) and prefrontal areas that might be related to mentalizing (medial prefrontal cortex) and performance monitoring (right prefrontal cortex). In contrast to episodic past and future thinking, counterfactual thinking recruits some of these areas more strongly and extensively, and additionally activates the bilateral inferior parietal lobe and posterior medial frontal cortex. We discuss these findings in view of recent fMRI evidence on the working of episodic memory and theory of mind.

Past fMRI research has demonstrated that to understand other people's behavior shown visually, the mirror network is strongly involved. However, the mentalizing network is also recruited when a visually presented action is unusual and/or when perceivers think explicitly about the intention. To further explore the conditions that trigger mentalizing activity, we replicated one of such studies (de Lange, Spronk, Willems, Toni, & Bekkering, 2008, Current Biology, 18, 454) under the minimal instruction to "view" pictures of unusual actions, without giving any "intention" instruction as in the original study. Contrary to earlier research, merely viewing unusual actions did not activate mentalizing areas. Instead, the dorsal anterior cingulate cortex was activated. We conclude that unusual actions are not sufficient by themselves to trigger mentalizing. In order to activate the mentalizing network without an intention instruction, a richer action context informative of the implausibility of the action might be a prerequisite.