Contextual processing in episodic future thought.

Remembering events from one's past (i.e., episodic memory) and envisioning specific events that could occur in one's future (i.e., episodic future thought) invoke highly overlapping sets of brain regions. The present study employed functional magnetic resonance imaging to test the hypothesis that one source of this shared architecture is that episodic future thought--much like episodic memory--tends to invoke memory for known visual-spatial contexts. That is, regions of posterior cortex (within posterior cingulate cortex [PCC], parahippocampal cortex [PHC], and superior occipital gyrus [SOG]) elicit indistinguishable activity during remembering and episodic future thought, and similar regions have been identified as important for establishing visual-spatial contextual associations. In the present study, these regions were similarly engaged when participants thought about personal events in familiar contexts, irrespective of temporal direction (past or future). The same regions, however, exhibited very little activity when participants envisioned personal future events in unfamiliar contextual settings. These findings suggest that regions within PCC, PHC, and SOG support the activation of well-known contextual settings that people tend to imagine when thinking about personal events, whether in the past or future. Hence, this study pinpoints an important similarity between episodic future thought and episodic memory.