RT Journal Article
SR Electronic
T1 “Overshoot” of O<sub>2</sub> Is Required to Maintain Baseline Tissue Oxygenation at Locations Distal to Blood Vessels
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 13676
OP 13681
DO 10.1523/JNEUROSCI.1968-11.2011
VO 31
IS 38
A1 Devor, Anna
A1 Sakadžić, Sava
A1 Saisan, Payam A.
A1 Yaseen, Mohammad A.
A1 Roussakis, Emmanuel
A1 Srinivasan, Vivek J.
A1 Vinogradov, Sergei A.
A1 Rosen, Bruce R.
A1 Buxton, Richard B.
A1 Dale, Anders M.
A1 Boas, David A.
YR 2011
UL http://www.jneurosci.org/content/31/38/13676.abstract
AB In vivo imaging of cerebral tissue oxygenation is important in defining healthy physiology and pathological departures associated with cerebral disease. We used a recently developed two-photon microscopy method, based on a novel phosphorescent nanoprobe, to image tissue oxygenation in the rat primary sensory cortex in response to sensory stimulation. Our measurements showed that a stimulus-evoked increase in tissue pO2 depended on the baseline pO2 level. In particular, during sustained stimulation, the steady-state pO2 at low-baseline locations remained at the baseline, despite large pO2 increases elsewhere. In contrast to the steady state, where pO2 never decreased below the baseline, transient decreases occurred during the “initial dip” and “poststimulus undershoot.” These results suggest that the increase in blood oxygenation during the hemodynamic response, which has been perceived as a paradox, may serve to prevent a sustained oxygenation drop at tissue locations that are remote from the vascular feeding sources.