Neural substrates underlying episodic future thinking: A voxel-based morphometry study

Episodic future thinking (EFT), the mental ability of projecting oneself into the future to pre-experience an event, has strong adaptive value for allowing people to consider potential consequences before taking actions. EFT includes two important components: the ability to construct detailed and vivid scenes of future events to achieve a goal (measured here by the EFT-sensory perceptual qualities scale) and the ability to subjectively experience "mental time travel" in which the person feels oneself to be in the future (measured here by the EFT-Autonoetic consciousness scale). However, little is known about the neuroanatomical structures of EFT. To shed light on this question, we employed voxel-based morphometry (VBM) to investigate the neural substrates underlying EFT. In Sample 1 (135 participants), EFT-sensory perceptual qualities was positively correlated with the gray matter (GM) volume of the hippocampus and putamen. EFT-Autonoetic consciousness was positively correlated with GM volume of the insula and amygdala, and negatively correlated with GM volumes of the medial frontal gyrus. The verification results from Sample 2 (59 participants) found that EFT-sensory perceptual qualities can be predicted by the GM volumes of the hippocampus and putamen, and EFT-Autonoetic consciousness can be predicted by the GM volumes of insula and amygdala. The present findings suggest that the hippocampus, putamen, and amygdala and insula are key regions for scene construction, goal-directed processing, and emotion respectively, and play important roles in the underlying structural neural substrates of EFT.