Optical survey of vagus nerve-related neuronal circuits in the embryonic rat brainstem

► We surveyed N.X-related neural circuits in the E16 rat brainstem by optical imaging. ► N.X stimulation elicited bilateral optical response areas in addition to the NTS. ► These responses are the neural activity in the second/higher-ordered nucleus. ► The bilateral areas are considered to correspond to the PBN and the A5 group. ► The N.X-related neural circuits are established as in adults from embryonic stages.