Further Studies on the Electrophysiological Anatomy of the Left and Right Giant Cells in Aplysia

Electrophysiological studies on cells of Aplysia central ganglia have become of general interest in recent years and have developed from work on the nature of integrative mechanisms (Arvanitaki & Chalazonitis, 1959; Tauc, 1955; Tauc & Hughes, 1963) to investigations of plastic change at a cellular level (Bruner & Tauc, 1966; Kandel & Tauc, 1965). Earlier work showed the range of phenomena found in a variety of cells, particularly in the abdominal ganglia, but research has now become more concentrated on certain cells which are readily identifiable in all preparations (Strumwasser, 1965 ; Hughes & Tauc, 1961 ; Kandel & Tauc, 1965). Of these cells, the large cell in the right upper quadrant, which is often called the giant cell, or right giant cell (RGC), has been used a great deal in studies on the basic phenomena of spike initiation in molluscan cells (Tauc, 1962). The anatomy of this cell was shown to be quite complex as a result of electrophysiological studies (Hughes & Tauc, 1963) which also revealed the presence of a comparable cell (LGC) on the left side of the C.N.S. Because of similarities in the general pattern of branching of these cells, they were considered homologous.