A combined neural-oxygen sensing multi-channel electrode array

We are developing a neural probe with integrated oxygen sensors to investigate the relationship between tissue oxygenation and neural activity within the brain. A quantitative understanding of this relationship at a submillimeter scale could enhance current non-invasive brain imaging techniques and extend their application in science and medicine. The neural probe is a microfabricated multichannel electrode array. Two of 16 recording sites of the array were converted to amperometric oxygen sensors by applying a polarization voltage relative to a reference electrode. The remaining electrode sites were used to record neural activity. In-vitro tests demonstrated a linear relationship between oxygen sensor current and dissolved oxygen. Preliminary in-vivo tests within the cat´s visual cortex demonstrated stimulus induced oxygen responses similar to those obtained using a conventional single channel Clark-style oxygen sensor.