Simultaneous MRI oximetry and electrical recording in the brain using ECoG electrodes infused with pO2 reporter molecules

Motivation: Current technologies limit the capabilities of measuring pO2 levels in multiple locations while recording neural activity using surface electrodes. Goal(s): To demonstrate that we can measure brain cortical pO2 and response to oxygen breathing simultaneously with electrical recordings. Approach: We utilized MRI to measure oxygenation levels using proton imaging of siloxanes to map tissue oxygenation levels (PISTOL). Tetradecamethylhexasiloxane (L6) was used as a pO2 reporter molecule and infused into the polydimethylsiloxane (PDMS) coating of ECoG electrodes implanted into rat brains (n=3). Results: We recorded an increase in pO2 between air and oxygen breathing states of three rats while simultaneously examining the neural activity. Impact: Researchers aiming to measure neuronal activity would benefit from the additional quantitative pO2 measurements during rest, brain stimulations, and disease models such as stroke.