Tetrodes for Monkeys

Abstract

We have adapted the Recce-O'Keefe tetrode for use in monkey cortex. Eleven penetrations have been made over macaque area MT to evaluate the mechanical and electrical properties of our design. Experiments have been made with 15 and 25 mu m insulated nichrome wire running through oil-filled 33 gauge stainless steel guide tubes. Electrically, the tetrodes compare favorably with traditional tungsten electrodes for single-unit isolation, and are superior for multi-unit recordings. Preliminary histology shows straight tracks at up to 12 mm tetrode extension.