Spatial construal of time and experimental design.

(A) The schematic diagram of spatial construal of time. It illustrates two core time concepts (sequence and duration) and two major perspectives on event series (mental time travel and watching). (B) Stimulus: a fictional religious ritual of 15 events following a specific sequence, enduring particular durations, and happening on predetermined parts of the day. The event phrases were randomly assigned to the events twice, generating two versions for even and odd numbers of participants. Only one version was illustrated here. (C) Task paradigm. In the external-perspective task, participants judged whether the target events happened in the same part of the day as the reference event. In the internal-perspective task, participants imagined themselves doing the reference events and judged whether the target event happened in the past or will happen in the future.

The reaction time of the corrected trials indicates that time was differently processed under internal and external perspectives1.

Neural correlates of specific perspectives and syllable length.

(A) Univariate contrast between external-perspective and internal-perspective tasks (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05). All the significant areas were in the right hemisphere. PreC: precuneus; RSC: the retrosplenial cortex; SFG: the superior frontal gyrus; AG: angular gyrus; SMA: supplementary motor area; SMG: supramarginal gyrus. (B) Parametric modulation of syllable length as a sanity check (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05). The activation level in the anterior part of the left superior temporal gyrus and the visual cortex positively correlated with syllable length.

Univariate contrast between internal- and external-perspective tasks (p < 0.001, cluster-level FWE corrected p < 0.05 across the whole cortex).

Neural correlates of event sequence.

A-C: Interaction effect between Task Type (i.e., external- vs. internal-perspective tasks) and Sequential Distance. (A) The only cortical region showing a significant interaction effect was localized in the right posterior parietal cortex (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05). (B) Regions of interest analysis shows that the activation level in the right posterior parietal cortex correlated with sequential distance positively in the external-perspective task and negatively in the internal-perspective task. (C) A further illustration of the relations between the activation level in the right posterior parietal cortex and sequential distance in the two tasks. The error bar indicates the standard error relative to the mean, and the shaded band around the linear regression line indicates 95% confidence interval. D-F: main effect of Sequential Distance. (D) The right hippocampal head shows a significant main effect of Sequential Distance within the mask of the bilateral hippocampus (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05; voxel-level p < 0.05 for illustration purposes). (E) Regions of interest analysis shows that the correlation between the activation level in the right hippocampal head and the sequential distance was independent of perspectives. (F) A further illustration of the relations between the activation level in the right hippocampal head and sequential distance in the two tasks. The error bar indicates the standard error relative to the mean, and the shaded band around the linear regression line indicates 95% confidence interval. **: p < 0.01; ***: p < 0.001

Neural correlates of event duration.

(A) The right hippocampal body shows a significant main effect of Duration within the mask of the bilateral hippocampus (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05; voxel-level p < 0.05 for illustration purposes). (B) However, regions of interest analysis shows that the correlation between the activation level in the right hippocampal body and Duration significantly differs in the internal- and the external-perspective task. (C) A further illustration of the relations between the activation level in the right hippocampal body and duration in the two tasks. The error bar indicates the standard error relative to the mean, and the shaded band around the linear regression line indicates 95% confidence interval. (D) Directly comparing the effects of Sequential Distance and Duration in the head and the body of the hippocampus shows a double dissociation pattern: the hippocampal head represented Sequential Distance but not Duration, while the hippocampal body represented Duration but not Sequential Distance. ***: p < 0.001

(A) Brain surface view of the univariate contrast between external-perspective and internal-perspective tasks (voxel-level p < 0.001, cluster-level FWE corrected p < 0.05). This view is transformed from the significant clusters in the MNI space in Figure 2A to the fsLR space using the toolbox neuromaps (https://github.com/netneurolab/neuromaps). (B) Brain surface view of the default network A and the default network B. They were respectively identified as the 8th and the 1st components among the 25 components of the “group-ICA” template from the UK Biobank brain imaging (https://www.fmrib.ox.ac.uk/ukbiobank/). We preserved the positive voxels above 7 in the MNI space and transformed them into the fsLR space using the toolbox neuromaps. Both plots are illustrated using the Connectome Workbench 2.0 (https://www.humanconnectome.org/software/connectome-workbench). They are displayed on an inflated surface against the group-averaged all sulcus image of 1096 young adults from the dataset of the Human Connectome Project (https://balsa.wustl.edu/reference/pkXDZ).