マウスの3コンパートメント葛藤課題における接近・回避行動の評価

抄録

Selecting an appropriate behavior is critical for survival in conflict situations during which animals face both appetitive and aversive stimuli. Animals in conflict situations exhibit several processes. First, they remain still in a safe place (suspension); once they decide to take action, they assess risks at a place where danger may occur (risk assessment) and finally reach the reward. However, most studies have not addressed these conflict processes. We developed a new experimental paradigm – the three-compartment conflict task – to quantitatively evaluate conflict processes. Our apparatus consisted of start, flat, and grid compartments. Mice were required to explore the grid compartment where they might receive foot shocks while trying to obtain sucrose. We found that applying foot shocks increased sucrose acquisition latency in the subsequent trials, reflecting an elevated conflict level throughout the trials. Time spent in the start compartment and the number of retreats were measured as parameters for conflict levels in suspension and risk assessment, respectively. Both parameters were increased by foot shocks. Treatment with diazepam decreased these parameters. Our new paradigm is a valuable tool for quantitatively evaluating conflict processes and contributes to the development of effective treatments for psychiatric disorders associated with maladaptive behaviors in conflict situations.