The in situ brainstem preparation for musk shrews, mice, and rats.

Animals were deeply anesthetized, decerebrated, and perfused with artificial blood. Recordings included the phrenic nerve activity, esophagus and mouth contraction force, and shoulder displacement. Electrocardiogram (ECG) was recorded from pins placed in the lateral edges of the preparation. Perfusion pressure was measured with a pressure tranducer located close to tip of the aorta perfusion catheter. The location of vagus nerve electrical stimulation is also shown. This preparation is adapted from Paton and colleagues [28]–[30], [36].