Variation in taste ganglion neuron morphology: insights into taste function and plasticity

Chemical information from food is transduced by cells in the taste bud (taste-transducing cells) and carried to the brain by peripheral taste ganglion neurons. These neurons are thought to act simply as cables without any transformation of the signal or circuitry between the taste-transducing cells and the neurons. However, these neurons vary in structure, particularly in the extent of their peripheral axon branching. Such structural differences would be expected to underlie differences in the number of taste-transducing cells providing convergent information to these neurons. However, axon branching may vary over time and morphological differences between neurons might also reflect neuron plasticity. Because taste-transducing cells die and are replaced, the morphology of neurons may change as they form connections with new cells within the taste bud. Modern genetic approaches may permit investigations of the complex relationship among gustatory neuron morphology, circuitry, and function. This review discusses potential relationships among peripheral taste neuron morphology, function, and plasticity to help advance our understanding of taste system function and dysfunction.