Polar plots showing response vector orientations determined for the following types of NTS units: cardiovascular units (A), respiratory units (B), GI units (C); convergent units (D), and unknown units (E). Response vector orientations were determined using wobble stimuli, usually at 0.2 Hz. The response vector orientations were plotted using a head-centered coordinate system, with 0° corresponding to ipsilateral ear-down (IED) roll tilt, 90° to nose-down (ND) pitch, 180° to contralateral ear-down (CED) roll, and −90° to (NU) nose-up pitch.