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. 2010 Dec 21;107(51):22356-9.
doi: 10.1073/pnas.1016823108. Epub 2010 Dec 6.

Consciousness of subjective time in the brain

Lars Nyberg  1 , Alice S N Kim, Reza Habib, Brian Levine, Endel Tulving
Affiliations

Consciousness of subjective time in the brain

Lars Nyberg et al. Proc Natl Acad Sci U S A. .

Abstract

"Mental time travel" refers to conscious experience of remembering the personal past and imagining the personal future. Little is known about its neural correlates. Here, using functional magnetic resonance imaging, we explored the hypothesis that mental time travel into "nonpresent" times (past and future) is enabled by a special conscious state (chronesthesia). Well-trained subjects repeatedly imagined taking one and the same short walk in a familiar environment, doing so either in the imagined past, present, or future. In an additional condition, they recollected an instance in which they actually performed the same short walk in the same familiar setting. This design allowed us to measure brain activity correlated with "pure" conscious states of different moments of subjective time. The results showed that the left lateral parietal cortex was differentially activated by nonpresent subjective times compared with the present (past and future > present). A similar pattern was observed in the left frontal cortex, cerebellum, and thalamus. There was no evidence that the hippocampal region is involved in subjective time travel. These findings provide support for theoretical ideas concerning chronesthesia and mental time travel.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Similarities in brain activity patterns for remembering and imagery are projected on a left cortical rendering view of the brain. Brain regions activated during the episodic retrieval task relative to the counting baseline task are plotted in red, and brain regions revealed in the comparison of imagery (past, present, and future) relative to counting are plotted in yellow. The overlap in activation patterns for REMEMBER (R) and IMAGERY (I) was pronounced in the inferior frontal cortex (x,y,z: R = −34,38,−16, Z = 5.07; I = −34,38,−16, Z = 4.49), fusiform gyrus (x,y,z: R = −32,−48,−10, Z = 5.87; I = −32, −50, −10, Z = 5.73), posterior cingulum/precuneus (x,y,z: R = −10,−60,62, Z = 6.23; I = −16,−58,60, Z = 5.83), and inferior parietal cortex (x,y,z: R = −40,−76,46, Z = 6.45; I = −40,−76,46, Z = 4.49). Threshold for illustration: P < 0.001 uncorrected.
Fig. 2.
Fig. 2.
Brain activity related to mental time travel. The contrast of nonpresent time (PAST, FUTURE, REMEMBER) with the present revealed differential activation in the left parietal cortex. The activation difference in the left parietal cortex was plotted relative to present for each of the nonpresent time conditions. Threshold for illustration: P < 0.005 uncorrected.
See this image and copyright information in PMC

References

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