A technique for recording local blood flow and neuronal activity with a single microelectrode

Abstract

A technique is presented for recording both local blood flow, by means of hydrogen clearance method, and neuronal activity of the cat's cortex using a single microelectrode. The requirements of electrodes for recording cerebral blood flow are different from those for recording extracellular spikes. Only electrodes within a small range of impedance (measured at 10 Hz) are suitable to record both. A bridge method is used for the recordings. The bridge signal is split in order to amplify cell activities and H₂ responses separately. Three examples demonstrate the method and the importance of appropriately selected electrodes.