Synchronous processing of temporal information across the hippocampus, striatum, and orbitofrontal cortex

Information processing for interval timing is supported by several brain regions, including the hippocampus, basal ganglia, and frontal cortical areas. However, little is known about the mechanism by which temporal information is processed cooperatively in the distributed brain network. Here, we investigated the neuronal processing of temporal information in the hippocampal CA1, dorsal striatum, and orbitofrontal cortex by simultaneously recording neuronal activity during a temporal bisection task. We found time cells representing elapsed time during the interval period across all three regions. Seeking a potential mechanism for the correlative representation of time, we found that theta oscillations were dominant in these areas and modulated the activity of these time cells. Moreover, the synchronization of the time cell pairs across the areas was also regulated by theta oscillations. Taken together, these results demonstrated the presence of synchronous activity of time cells across the three areas on a fine time scale, which was supported by theta oscillations. In addition, decoding analysis revealed that the activity of the time cells in these areas correlated with the rats decisions based on their internal time estimation, with the decoded time also showing correlations across the three regions. Thus, the cooperative activity of time-cell assemblies in the three regions reflected the recognition of elapsed time in the rats. In conclusion, these results demonstrate the pivotal role of neuronal synchronization of time cells in supporting temporal processing in the distributed brain network.