Fig. 7. Morphological and physiological properties of cells SIN1. A. Morpholo gy of cell SIN1 in the subesophageal ganglion and segmental ganglion 1. Cell S IN1 was drawn from a Lucifer Yellow fill. B. Interaction between cell SIN1 pai r. Intense stimulation of one cell SIN1 only slightly increases the firing frequency of the other cell SIN1.