Fig. 1

Typical recordings showing the effects of electrical stimulations of the mesencephalic ventral areas on arterial blood pressure, original and mean femoral blood flow, and femoral vascular conductance in an anesthetized, paralyzed cat. A The six sites of the stimulating electrode are shown in the frontal plane 3.0–3.5 mm anterior to the interaural line [14]. B Horizontal bars at the bottom indicate the 30-s period of electrical stimulation of each mesencephalic site. SC superior colliculus, CGN nucleus corporis geniculati medialis, PAG periaqueductal gray, RN red nucleus, SN substantia nigra, VTA ventral tegmental area, IPN nucleus interpeduncularis, cp cerebral peduncle