Ceramic-based multisite electrode arrays for chronic single-neuron recording

A method is described for the manufacture of a microelectrode array for chronic, multichannel, single neuron recording. The ceramic-based, multisite electrode array has four recording sites patterned onto a ceramic shaft the size of a single typical microwire electrode. The sites and connecting wires are applied to the ceramic substrate using a reverse photolithographic procedure. Recording sites (22*80 (mu)m) are separated by 200 (mu)m along the shaft. A layer of alumina insulation is applied over the whole array (exclusive of recording sites) by ion-beam assisted deposition. These arrays were capable of recording single neuron activity from each of their recording sites for at least three weeks during chronic implantation in the somatosensory cortex of rats, and several sites had recordings that lasted for more than 8 weeks. The vertical arrangement of the recording sites on these electrodes is ideal for simultaneously recording across the different layers of brain areas such as the cerebral cortex and hippocampus in chronic preparations.