Characterization of an Insect Neuron which cannot be Visualized in situ

Abstract

The inability to visualize a target is a problem common to intracellular recording in many nervous systems. This problem can be mitigated by the injection of stain into the neurons of interest. By determining the geometry of a neuron and correlating that geometry with respect to external landmarks, it is possible to record routinely from the dendrites and somata of single, physiologically identifiable but “invisible” neurons in the central ganglia of crustacea (Zucker et al., 1971; Zucker, 1972a, b, c) and insects (illustrated here). In the insects, injection of stain into “blindly” impaled neurons can provide unique morphological identification of those neurons. By combining intracellular recording and staining techniques, we can now obtain meaningful data on the integrative processes underlying behavior in this well-studied group of organisms. In addition, intracellular staining techniques should facilitate analysis of the geometry of neurons which develop under various experimental conditions.