CBV fMRI with USPIO was used to study odorant-induced olfaction in rats.
Activations were observed in the olfactory bulb (OB) and higher olfactory regions (HOR).
Responses to repeated stimulations adapted more in HOR than in OB.
During continuous odor exposures, adaptation was only observed in HOR, not OB.
The results support that HOR plays a more significant role than OB in habituation.