Intelligent agents can significantly improve their predictive and problem-solving performanceby possessing metacognitive skills to monitor and control their own thinking, knowledge, cognition, andlearning. One of the most important abilities is introspection, which involves recall about past episodes andimagination on counterfactual time developments. Because such abilities are not yet realized by currentartificial intelligence, it is significant to refer to the brain mechanism. In recent years, there has been agrowing body of knowledge on metacognition and introspection in the brain, but the full extent of itsinformation processing is still unclear. In this paper, a working hypothesis of metacognition in the brain isproposed, based on the knowledge that representations that become conscious in the brain are independentof the working memory. The proposed model encodes a series of indices for object-level representations onthe neocortex to representations on the hippocampus, and then monitors and controls the representations onthe hippocampus from the meta-level through a part of the neocortex. Next, anatomical findings of Papezcircuit were collected, that circuit sit between the hippocampus and the higher-order cortical area, and thesefindings were organized into an information flow diagram. The retrosplenial cortex (RSC) - entorhinalcortex pathway is predicted as a plausible candidate for the transmitting metacognitive control signals fromthe neocortex to the hippocampus from the analysis of the flow diagram.