Stimulus temperature modulates the psychophysical dimensions of salt taste

Temperature is a fundamental yet understudied parameter of gustatory experience. In this study, we designed a set of experiments that examined how stimulus temperature affects the motivational and sensory-discriminative properties of sodium (NaCl) and nonsodium (KCl) salts. In brief-access tests, water-deprived mice consistently preferred cool (14°C) over warm (36°C) stimuli regardless of salt content. Progressive ratio tests confirmed that cool stimuli possess greater appetitive efficacy, suggesting that, under our experimental conditions, water deprivation may confound temperature preferences in brief-access procedures. In contrast, operant conditioning tasks revealed robust temperature effects on sensory-discriminative function. In a two-response taste detection task in which mice were trained to distinguish each salt from water, enhanced sensitivity to both NaCl and KCl was observed at 36°C compared with 14°C, with detection thresholds significantly lower at warm temperatures. Critically, in discrimination tasks where mice were required to distinguish between NaCl and KCl with stimulus intensity controlled by anchoring concentrations at their respective detection thresholds, mice showed significantly impaired discrimination performance at 36°C compared with 14°C, indicating that the qualitative signatures of the two salts became perceptually more similar at the warmer temperatures. These findings demonstrate that temperature profoundly modulates the sensory-discriminative properties of salts: although warm temperatures enhance detection sensitivity, they simultaneously reduce qualitative discriminability between sodium and nonsodium salts. Overall, these results have implications for the operational principles of taste function and highlight the promising possibility that temperature manipulation could serve as an effective strategy for dietary sodium reduction.NEW & NOTEWORTHY Despite being a fundamental parameter of gustatory experience, how temperature shapes taste perception remains poorly understood. Using a multifaceted behavioral approach in mice, we found that water deprivation confounds temperature-driven motivational responses. In contrast, warm temperatures both lowered detection thresholds for NaCl and KCl and impaired discrimination between the two salts, revealing that temperature modulates the perceptual similarity between sodium and nonsodium salts with implications for taste neuroscience and sodium reduction strategies.