Heart rate changes related to risky selections and outcomes in rat gambling tasks

Risk-taking behavior is crucial to increase potential outcomes and alter arousal states in the brain and body represented by heart rates. In this study, we monitored changes in heart rate as rats performed a 50:50 gambling task in which they selected either a certain outcome with 100 % probability (sure option) or a double outcome with 50 % probability (risky option). When rats selected risky options, they exhibited significantly greater decreases in their heart rates before selection than when they selected certain options. In addition, we observed significantly larger increases in heart rates when the rats recognized larger outcomes after selecting the risky options than the sure options. Similar dynamic changes in heart rates were observed in a 25:75 gambling condition with different reward magnitudes and probabilities. These results demonstrate that animals can dynamically alter their heart rates in response to risky selection and outcomes.