Neural Correlates of Temporal Presentness in the Precuneus: A Cross-linguistic fMRI Study based on Speech Stimuli

Abstract

The position of any event in time could be in the present, past, or future. This temporal discrimination is vitally important in our daily conversations, but it remains elusive how the human brain distinguishes among the past, present, and future. To address this issue, we searched for neural correlates of presentness, pastness, and futurity, each of which is automatically evoked when we hear sentences such as “it is raining now,” “it rained yesterday,” or “it will rain tomorrow.” Here, we show that sentences that evoked “presentness” activated the bilateral precuneus more strongly than those that evoked “pastness” or “futurity.” Interestingly, this contrast was shared across native speakers of Japanese, English, and Chinese languages, which vary considerably in their verb tense systems. The results suggest that the precuneus serves as a key region that provides the origin (that is, the Now) of our time perception irrespective of differences in tense systems across languages.

The Dark Energy Sector of Generalised Proper Time

“…The fact that the strongest response of the precuneus is to presentness is presumably important for survival, with a clear evolutionary advantage in focussing upon an accurate representation of the current situation of the individual and state of affairs of the external world. Further, the response to the 'future' comes second, as is again reasonable given the need to make plans for upcoming events, while response to the 'past' comes third, perhaps since 'it is no use crying over spilt milk' ( [85] figure 3D and discussion).…”

“…In particular it has been demonstrated that the precuneus plays a central role in the neural basis for our subjective experience of the present, that is the 'now' of our time perception [85]. In fact precuneus activation is found to be significant in association with subjective feelings of the past, present and future, as evoked by speech stimuli, with the response up to three times greater for the experience of 'presentness', in a manner that is independent of the language used.…”

“…In turn a basis for a continuous temporal flow can itself be identified as an intrinsic subjective aspect of the mind emerging from neural structures in the brain as reviewed in this subsection. The precuneus, located in a central interhemispheric region of the cerebral cortex, plays a key role in this 'chronogenesis' [80,85].…”

“…Figure 6: For the theory based upon generalised proper time physical structures of the universe derive directly from the arithmetic substructures implicit in the flow of time alone, as reviewed in section 3 and represented in figures 3 and 5.In turn a basis for a continuous temporal flow can itself be identified as an intrinsic subjective aspect of the mind emerging from neural structures in the brain as reviewed in this subsection. The precuneus, located in a central interhemispheric region of the cerebral cortex, plays a key role in this 'chronogenesis'[80,85].…”

Malleability and fluidity of time perception

“…In addition, time perception is impaired in disorders of the precuneus/posterior cingulate gyrus 35 and supramarginal gyrus 36 . In particular, the precuneus may contribute to our sense of “presentness”, providing the “now” in the passage of time 37 , 38 .…”