| “Sequential activity in brain networks has been observed across multiple species, neural structures, and behavioral contexts. For instance, a group of neurons named “”time-cells”” that fire sequentially during unfilled delay intervals has been widely discovered in the hippocampus. Interestingly, temporal information can be easily decoded through the population activities of this cell ensemble. To explain the timing mechanism behind time cells, a theoretical model was proposed that a set of leaky integrators performs a Laplace transform on the stimulus function, and time cells fire sequentially to estimate the present time by approximating the inversion of the Laplace transform. However, little experimental evidence was discovered to support the existence of these “”leaky integrators””. In this project, we identified a group of neurons in monkey’s precuneus that fire immediately after the video onset and decay back to the baseline with different rates. Furthur analyses illustrate that these neurons indeed integrate information from encoding for temporal order judgement. To summarize, these findings provide strong quantitative evidence that the monkey’s precuneal neurons construct a temporal record of the past by a spectrum of time constants in support of memory retrieval. “ |
