In humans and animals, episodic memory requires the concerted association of objects, space and time coordinated by the entorhinal cortex (EC)-hippocampal (HPC) network. While the encoding of space and object associations in this network have been well explored, our understanding of the time-related aspect of episodic memory is only very recently coming to light. For instance, the input from medial EC layer III cells to CA1 pyramidal cells is important for the temporal association of discontiguous events. While most cognitive and motor phenomena temporal association memory must be regulated for optimal adaptive benefit, virtually nothing is known about the underlying mechanisms of this regulation. In my talk, I will provide the next major step by mapping and characterizing an unsuspected neuronal circuit within the EC-HPC network and examining the effect of its optogenetic manipulations on a temporal association learning. I report a distinct set of excitatory neurons (Island cells), which appear in a curvilinear matrix of bulb-like structures in layer II of the entorhinal cortex, project directly to pyramidal cell dendrite-targeting inhibitory neurons in the hippocampal CA1 area, and control the formation of temporal association memory driven by layer III of the medial entorhinal cortex through the feedforward inhibition to control the strength and duration of temporal association in trace fear memory. Together, the two EC inputs into CA1 area comprise a control circuit for temporal association memory.