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Abstract Recent behavioral studies have shown that humans possess self-awareness of their individual timing ability in that they can discern the direction of their timing error. However, in these studies which included a single repeat (re-do) trial for each duration, it remains unclear whether the reduction in errors in the re-do trials was due to self-awareness of individual timing ability or because the participants used the feedback from the initial trials to improve on the re-do ones. To investigate this further, we conducted a behavioral study in which subjects were divided into two groups: one in which the “re-do” phase occurred frequently, but not always (80% of trials; called the “high-double” group), and one in which re-do trials were rare (20% of trials; called the “low-double” group). This was done to test the possibility of subjects relying on the re-do trials as a method of improvement. Subjects significantly improved in their performance on re-do trials regardless of whether re-dos were rare or frequent. Further, an unexpected finding was observed, where subjects in the low-double group also overall performed better than those in the high-double group. This finding suggests that subjects, knowing that re-do opportunities were rare, engaged better timing at the outset; yet these subjects still improved on re-do trials, suggesting humans are able to incorporate both global uncertainty and feedback. 

Abstract A longstanding issue concerns the extent to which episodic autobiographical memory (EAM) and episodic future thinking (EFT) are the expression of the same cognitive ability and may be dissociated at the neural level. Here, we provided an updated picture of overlaps and dissociations between brain networks supporting EAM and EFT, using Activation Likelihood Estimation. Moreover, we tested the hypothesis that spatial gradients characterize the transition between activations associated with the two domains, in line with accounts positing a transition in the relative predominance of their features and process components. We showed the involvement of a core network across EAM and EFT, including midline structures, the bilateral hippocampus/parahippocampus, angular gyrus and anterior middle temporal gyrus (aMTG) and the left superior frontal gyrus (SFG). Contrast analyses highlighted a cluster in the right aMTG significantly more activated during EFT compared with EAM. Finally, gradiental transitions were found in the ventromedial prefrontal cortex, left SFG, and bilateral aMTG. Results show that differences between EAM and EFT may arise at least partially through the organization of specific regions of common activation along functional gradients, and help to advocate between different theoretical accounts. 

This work proposes how humans perceive the difference between two simultaneously presented tempos and bring them into perceived synchrony. EEG data provide evidence of entrainment to both tempos that move into alignment, and transcranial alternating current stimulation (tACS) data provide causal evidence that strengthening one tempo improves performance. 

Abstract Previous studies have demonstrated that human participants can keep track of the magnitude and direction of their trial-to-trial errors in temporal, spatial, and numerical estimates, collectively referred to as “metric error monitoring.” These studies investigated metric error monitoring in an explicit timing/counting context. However, many of our judgments may also depend on temporal mismatches between stimuli where the temporal information is not processed explicitly, which eventually brings about the simultaneity perception. We investigated whether participants can monitor errors in their simultaneity perception. We tested participants in temporal orer judgment (TOJ) task, where they judged which of the two consecutive stimuli (one on each side of the screen) appeared first and reported their confidence rating for each TOJ. The results of all four experiments showed that the confidence judgements for correct judgments increased and for incorrect judgments decreased with longer absolute SOA. A more granular analysis showed that participants could only monitor their errors for left-first and bottom-first judgments, which suggests a metacognitive spatial–temporal association of response codes (STEARC) effect. 

Abstract In this study, we ran a meta-analysis of neuroimaging studies to pinpoint the neural regions that are commonly activated across space, time, and numerosity, and we tested the existence of gradient transitions among these magnitude representations in the brain. Following PRISMA guidelines, we included in the meta-analysis 112 experiments (for space domain), 114 experiments (time domain), and 115 experiments (numerosity domain), and we used the activation likelihood estimation method. We found a system of brain regions that was commonly recruited in all the three magnitudes, which included bilateral insula, the supplementary motor area (SMA), the right inferior frontal gyrus, and bilateral intraparietal sulci. Gradiental transitions between different magnitudes were found along all these regions but insulae, with space and numbers leading to gradients mainly over parietal regions (and SMA) whereas time and numbers mainly over frontal regions. These findings provide evidence for the GradiATOM theory (Gradient Theory of Magnitude), suggesting that spatial proximity given by overlapping activations and gradients is a key aspect for efficient interactions and integrations among magnitudes. 

Error monitoring is an essential human ability underlying learning and metacognition. In the time domain, humans possess a remarkable ability to learn and adapt to temporal intervals, yet the neural mechanisms underlying this are not well understood. Recently, we demonstrated that humans exhibit improvements in sensorimotor time estimates when given the chance to incorporate feedback from a previous trial (Bader and Wiener, 2021), suggesting that humans are metacognitively aware of their own timing errors. To test the neural basis of this metacognitive ability, human participants of both sexes underwent fMRI while they performed a visual temporal reproduction task with randomized suprasecond intervals (1.5-6s). Crucially, each trial was repeated following feedback, allowing a “re-do” to learn from the successes or errors in the initial trial. Behaviorally, we replicated our previous finding that subjects improve their performance on re-do trials despite the feedback being temporally uninformative (i.e. early or late). For neuroimaging, we observed a dissociation between estimating and reproducing time intervals, with the former more likely to engage regions associated with the default mode network (DMN), including the superior frontal gyri, precuneus, and posterior cingulate, whereas the latter activated regions associated traditionally with the “Timing Network” (TN), including the supplementary motor area (SMA), precentral gyrus, and right supramarginal gyrus. Notably, greater DMN involvement was observed in Re-do trials. Further, the extent of the DMN was greater on re-do trials, whereas for the TN it was more constrained. Finally, Task-based connectivity between these networks demonstrated higher inter-network correlation on initial trials, but primarily when estimating trials, whereas on re-do trials communication was higher during reproduction. Overall, these results suggest the DMN and TN work in concert to mediate subjective awareness of one’s sense of time for the purpose of improving timing performance. Significance StatementA finely tuned sense of time perception is imperative for everyday motor actions (e.g., hitting a baseball). Timing self-regulation requires correct assessment and updating duration estimates if necessary. Using a modified version of a classical task of time measurement, we explored the neural regions involved in error detection, time awareness, and learning to time. Reinforcing the role of the SMA in measuring temporal information and providing evidence of co-activation with the DMN, this study demonstrates that the brain overlays sensorimotor timing with a metacognitive awareness of its passage. 

Abstract To navigate through the environment, humans must be able to measure both the distance traveled in space, and the interval elapsed in time. Yet, how the brain holds both of these metrics simultaneously is less well known. One possibility is that participants measure how far and how long they have traveled relative to a known reference point. To measure this, we had human participants (n = 24) perform a distance estimation task in a virtual environment in which they were cued to attend to either the spatial or temporal interval traveled while responses were measured with multiband fMRI. We observed that both dimensions evoked similar frontoparietal networks, yet with a striking rostrocaudal dissociation between temporal and spatial estimation. Multivariate classifiers trained on each dimension were further able to predict the temporal or spatial interval traveled, with centers of activation within the SMA and retrosplenial cortex for time and space, respectively. Furthermore, a cross-classification approach revealed the right supramarginal gyrus and occipital place area as regions capable of decoding the general magnitude of the traveled distance. Altogether, our findings suggest the brain uses separate systems for tracking spatial and temporal distances, which are combined together along with dimension-nonspecific estimates.