Activity of baroreceptor-modulated neurons in the nucleus tractus solitarius (NTS) was recorded extracellularly during selective pressure stimulation of carotid baroreceptors, using an isolated carotid sinus preparation in anesthetized dogs. One of two different patterns of activity was recorded from individual baro-sensitive neurons in response to slow ramp increases in carotid sinus pressure. The cause of these two distinct firing patterns is not known but preliminary results indicate that it may be due in part to input from different functional types of baroreceptors. These results suggest that some differentiation in blood pressure control may be encoded in the responses of central baro-sensitive neurons in the NTS.