Examinations of CS and US preexposure and postexposure in conditioned taste aversion: Applications in behavioral interventions for chemotherapy anticipatory nausea and vomiting

Examining CS or US preexposure and postexposure to dissociate conditioned stimulus (CS)-unconditioned stimulus (US) conditioned learning and apply these findings to alleviate anticipatory nausea and vomiting are crucial for cancer chemotherapy patients. The present study utilized a conditioned taste aversion (CTA) paradigm in rats to develop a new behavioral intervention. Experiment 1 evaluated Control, Conditioning, CS preexposure, and CS postexposure groups. Experiment 2 evaluated Control, Conditioning, US preexposure, and US postexposure groups. After conditioning in both experiments, rats were given the CS alone without the US once per day over three trials, and their conditioned taste aversion was measured. The results showed that both CS preexposure and US preexposure interfered with subsequent CS-US conditioning, indicating that both induced proactive interference. Although CS postexposure interfered with prior CS-US conditioning, which indicated extinction, US postexposure did not alter CS-US conditioning. The findings should be considered for the development of new nonpharmacological clinical interventions for cancer patients with chemotherapy-induced anticipatory nausea and vomiting.