Sodium appetite appears to be an excellent model to study the neural mechanisms of motivation. In this issue of Chemical Senses, experiments by St John (2016) challenge 2 hypotheses for how a systemic sodium deficit guides an animal to find and ingest more Na ions in the environment. Both hypotheses deal with modifications of the sensory neural code produced by Na+ ions on the tongue. One envisions a change in the Na+ signal amplitude. A reduction could make the strong Na+ signals less aversive; an increase, weak signals more noticeable. The other hypothesis requires no changes in the identity or amplitude of the Na+ signal, but a shift in its hedonic tone toward sweetness or reward. The results of the 3 behavioral experiments render both explanations unlikely but fail to suggest alternatives.