Olanzapin is a commonly used atypical antipsychotic drug. We hypothesize that long term therapy of olanzapin could alter region dependent blood brain perfusion, which we tested by arterial spin labeling (ASL) MR imaging. Statistical evaluation of the ASL results in the hippocampus, somatosensory cortex and piriform cortex revealed significantly lower somatosensory cortex perfusion in olanzapin-treated animals.