​​​Talk from Tatsuhiro Hisatsune - University of Tokyo

Short abstract:

The hippocampal formation is not only processing spatial information, but also perceiving temporal information. Investigating how the silencing of newborn neurons (NBN) affects the hippocampus's time perception capabilities is fascinating, therefore this study examined the impact of NBN silencing on time perception through a temporal bisection in mouse models of contextual fear conditioning and operant drinking learning. In the temporal bisection evaluation, by presenting several intermediate durations between two standard lengths of short (2 sec) and long (8 sec) durations, the study observed the responses of subjects to different time lengths, measuring their behavior assessing the point of subjective equality (PSE). The results revealed an earlier shift of long duration PSE in NBN group from the two experimental settings, suggesting that NBN silencing may impair the hippocampus's role of time perception, leading to time dilation incident. For an in-depth exploration, examining the impact of silenced NBNs on the time dilation, awake task-fMRI experiments were conducted in 14T-MRI (Ref. 1), along with functional connectivity (FC) analysis after resting-state fMRI. Awake-fMRI shows reduced brain-wide BOLD activation with elevated hippocampal activation in NBN mice, probably due to the dys-inhibition of dentate gyrus local circuit in NBN-mice. The rs-fMRI analysis pointed out dysregulated FC in both intra- and extra- hippocampal networks in NBN. Especially, reduced circuit stability was observed in NBN group along with the reduced interaction between the dorsal hippocampus and the medial prefrontal cortex, signifies potential disruptions in executive function including temporal perception.

​(1) Li et al., Science dvances 10, eadk4741 (2024).​

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