FIG. 1.

A horizontal slice was obtained that permits the electrical stimulation of the trigeminal nerve rootlet while keeping the pathway to cardiac vagal neurons in the nucleus ambiguus intact as illustrated in A. Cardiac vagal neurons in the nucleus ambiguus were identified by the presence of the fluorescent tracer, XRITC (B) previously injected into the pericardial sac. Patch electrodes were positioned onto the surface of the cardiac vagal neurons for whole cell recording using IR light and an IR sensitive camera as illustrated in C.