Pavlovian conditioning of taste aversion using a motion sickness paradigm

Objective: Pavlovian conditioning of taste aversion has rarely been investi gated in healthy humans using motion sickness as the unconditioned stimulus (US). Methods: Ninety subjects were pretested for susceptibility to illuso ry motion (vection) in a rotating drum. Thirty-two subjects susceptible to pseudomotion were assigned randomly to two groups and received either water 1 hour before rotation and a novel taste (elderberry juice, conditioned st imulus, [CS]) immediately before rotation in a rotating chair (conditioning group), of the sequence of water and juice was reversed (control group). D uring the test session 1 week later, all subjects were exposed to water 1 h our before and juice immediately before rotation. The amount of liquids ing ested, nausea ratings, rotation tolerance, and blood levels of hormones (AC TH, ADH, PP) were evaluated. Results: Subjects in the conditioning group de veloped taste aversion toward the novel taste, but not subjects in the cont rol group. Postrotation nausea rating was affected marginally by conditioni ng, but rotation tolerance was not changed by conditioning. ACTH and ADH bu t not PP levels increased with rotation, but were unaffected by conditionin g. Conclusions: Pavlovian conditioning of behavioral, but not of endocrine, indicators was effective in susceptible subjects using a rotating chair as US and a single CS-US pairing.