The results of our first functional magnetic resonance imaging study provide new insights into how personal events are temporally organized in the human brain. In brief, we found that a distributed network of brain regions (i.e. occipital, temporal, parietal, frontal, and subcortical regions) is involved in mental projection across the past and future. Interestingly, we observed that most of these regions exhibited neural modulation as a function of life span and/or as a function of compatibility with a back-to-front mental timeline, suggesting a key role for these regions in representing the temporal organization of personal events. Furthermore, the closer the personal events, the stronger the functional coupling between regions of the parietotemporal network and the visual cortex and hippocampus. Revealing the neural underpinnings of mental travel across past and future autobiographical events as a function of temporal reference and distance will significantly advance the field of neuropsychology of memory. Although several studies have investigated neuropsychological aspects of episodic autobiographical memory and episodic future thinking, little was known about the fine-grained spatiotemporal dynamics of mental travel prior to our study. Our results reveal a network of brain areas involved in mental projection across the past and future. These results would inform new investigations aimed at testing the causal contribution of these brain areas to the human ability to place oneself in the past and in the future.
As a corollary aspect of the project, we provided new evidence about validity and reliability of the autobiographical fluency test to be used in both clinical and experimental contexts to test autobiographical memory. This test taps both episodic and experience-near personal semantics. The neural networks underlying these components were also described.
