In vivo visualization of individual neurons in arthropod ganglia facilitates intracellular neuropil recording

Summary A simple method for the in vivo visualization of dye filled cells by laser illumination is used to characterize neurons in situ in the segmentai ganglia of the locust and the crayfish (Fig. 1). Neuron visualization provides the structural information necessary for identification of cells during an ongoing physiological experiment (Figs. 2, 3). Sequential penetrations of soma and neuropil as well as simultaneous double neuropil penetrations of spiking and nonspiking cells are facilitated by the visual control afforded by neuron visualization (Figs. 4, 5, 6). Furthermore, neuron visualization allows the sampling of cellular properties at multiple, predetermined sites in the dendritic and axonal arbors of identified neurons (Fig. 7) and aids in establishing synaptic connectivity through double neuropil recordings (Fig. 8).