Perfusion-related BOLD fMRI to transient hypoxic stimuli in awake vs. anesthetized mice

Motivation: Non-invasive mapping of cerebral perfusion is essential for understanding neurodegenerative diseases. To evaluate the impact of anesthesia on cerebral perfusion, studies need to be conducted under awake conditions. Goal(s): To investigate differences in cerebral perfusion and spatiotemporal BOLD responses to hypoxic stimulation in awake and anesthetized mice. Approach: BOLD MRI responses to a hypoxic stimulus (90%N2) were measured in both awake and 0.5% isoflurane anesthetized mice. Results: In the awake state, the reduced negative BOLD signals were followed by post-stimulus overshoot in cortical regions, compared to anesthetized condition, indicating lower CBV and CBF across the brain under awake state. Impact: We identified differences in cerebral perfusion-related properties between awake and anesthetized conditions in normal mice. Our findings indicate that our awake perfusion imaging approach can be applied to neurodegenerative disease models.