Anatomical relationships between sensory afferent arborizations in the cricket cercal system.

The anatomical relationships between sensory afferents within a topographic map in the cricket cercal sensory system were studied using a computer-based reconstruction system developed in our laboratory. Individual identified mechanosensory afferents were characterized physiologically, stained with cobalt, silver intensified, and reconstructed in three dimensions. All reconstructions were scaled to a common standard. The results indicate that there is very little variability in the position or extent of the terminal arborization of identified mechanosensory afferents. The topographic map was divided relatively equally into four regions representing each of the four classes of afferents studied. These regions were discrete but not completely segregated. Approximately 30% of the topographic map contained regions of overlap between two or more classes or afferents.