John Lowry1, Karen Griffin2, Stephen McHugh3, Nicola Sibson4
1Department of Chemistry, National University of Ireland, Maynooth, Ireland; 2University College Dublin, Ireland; 3Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom; 4Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, Oxfordshire, United Kingdom
Long-term in-vivo electrochemistry (LIVE) enables real-time measurement of brain metabolites. Here we have simultaneously obtained BOLD fMRI and amperometric LIVE tissue oxygen data from rat cerebral cortex, during both increases and decreases in inspired oxygen. BOLD and tissue oxygen measurements demonstrated close correlation during both complete oxygen removal (negative responses) and increases in inspired oxygen (positive responses). Our findings demonstrate the feasibility of obtaining real-time metabolite information during fMRI acquisition. The results show that the BOLD signal provides a close correlate of the tissue oxygen dynamics or, alternatively, that tissue oxygen concentration can predict the magnitude of the BOLD response.