| Abstract: | The distribution of facial sensory axons to the tongue and palateof the rat was determined in relation to the spatial distributionof taste buds. Gross dissections and serial reconstruction ofsilverstained material revealed five divisions of the chorda-lingualnerve in the tongue and four divisions of the greater petrosalnerve in the palate. Axon counts were made in normal and de-efferentedchorda tympani and greater petrosal nerves from montages ofelectron micrographs. De-efferented facial nerves were preparedby intracranial section of the nervus intermedius and motorroot prior to sacrifice. Cell bodies were counted in the geniculateganglion and the total number of axon profiles in the chordatympani and greater petrosal nerves exceeded the number of ganglioncells by 30%. The greater petrosal nerves contained about threetimes as many profiles as the chorda tympani nerves with theprincipal disparity among unmyelinated axons. Taste bud numberson the palate and anterior tongue were nearly equivalent; however,their densities per unit of surface area varied 150 fold betweenregions. On the tongue, taste bud density seemed not to be correlatedwith the number of axons directed to a region as there was anearly linear distribution of axons from the base to the apex. |
