Understanding physiological interactions between the central and peripheral nervous systems requires an experimental strategy to simultaneously monitor activity patterns of the brain and peripheral organs. In this study, we developed a novel method to record extracellular field potential signals from a wide range of brain regions together with electrocardiograms, electromyograms, and breathing signals from a freely moving rodent. This method collects all recorded signals into a single device mounted on an animal’s head, allowing the reduction of experimental costs and the simplification of data processing. The methodological concept is applicable to a number of biological research issues of how the brain–body association is altered in response to various environmental changes, emotional challenges, and acute and chronic dysfunction of internal organs.