Palatability changes during attenuation of flavor neophobia assessed with licking microstructure and taste reactivity

Novel flavors elicit a neophobic response, which attenuates as they are recognized as safe. The attenuation of taste neophobia has been widely studied through measuring overall intake, however, changes in hedonic value have not been systematically considered. We conducted two experiments to assess, in both male and female Sprague-Dawley rats, the hedonic changes across a six-day attenuation of the neophobia process using two different methods. In the first experiment, we analyzed the microstructure of licking, which affords measuring both consumption and hedonic value at the same time. This study used animals heterozygous for Cacna1c (a key genetic risk factor for multiple psychiatric disorders associated with anhedonia) and wild type controls. In the second experiment, we used the taste reactivity test. The analysis of licking microstructure, but not the taste reactivity test, was sensitive to hedonic value changes during attenuation of the neophobia. Females showed more hedonic reactivity than males in both experiments, and there was no effect of the Cacna1c manipulation. The findings highlight the importance of considering hedonic factors in the attenuation of neophobia process. The difference between the hedonic assessment methods in the sensitivity to hedonic changes during attenuation of neophobia is discussed, although this is complicated by differences in the procedures themselves (e.g. voluntary vs involuntary consumption).