Miaoetectiodes fabricated using integrated-circuit technology are shown to be suitable for extracellular single-unit recording, and the factors influencing electrode-cell coupling are discussed. Electrode tip size as well as location is found to be critical in recording high spike amplitudes, suggesting that the paths for current flow in central nervous system (CNS) tissue may be extremely small. A. Starr was with the Department of Neurology, Stanford University, Stanford, Calif. He is now with the Department of Neurology, University of California College of Medicine, Irvine, Calif. Copyright © 1973 by The Institute of Electrical and Electronics Engineers, Inc.