Figure 5.

Blood-oxygenation-level-dependent (BOLD) (A), relative cerebral blood flow (rCBF) change (B), relative cerebral arterial blood volume (rCBV_a) change (C), ΔCBF (D) and ΔCBV_a (E) during CO₂ stimulation. Hypercapnia-induced BOLD and rCBF responses in spontaneously hypertensive rats (SHR) were significantly higher than those in Wistar–Kyoto (WKY) rats in all regions examined (*P<0.05). ΔCBV_a responses between both groups were similar, whereas relative CBV_a responses appeared higher for hypertensive animals. Error bars: s.e.m.; CPU, caudate putamen; Th, thalamus; Hip, hippocampus.