Department of Psychology, San Diego State University, San Diego, CA, United States.
Behav Brain Res. 2011 Oct 1;223(2):371-5. doi: 10.1016/j.bbr.2011.05.004. Epub 2011 May 10.
The present study examined the anticipation of future reward in 7-mo- and 26-mo-old Fischer 344/Brown Norway rats. Young and old rats were divided randomly and assigned into one of two conditions. In the Contrast Condition, subjects were given a water solution containing 2% sucrose for 3 min followed immediately by a water solution containing 32% sucrose for 3 min. In the No-Contrast Condition, subjects were given a water solution containing 2% sucrose for 3 min followed immediately by a water solution containing 2% sucrose for 3 min. Across 10 days of testing in the Contrast Condition, young rats showed significantly less intake of the less preferred 2% sucrose solution, whereas old rats showed increased intake of the 2% sucrose solution. Young rats showed a significant increase in intake of the preferred 32% sucrose solution compared to aged rats across the 10-day testing period with the exception of days 8-10 where intake did not differ between groups. In the No-Contrast Condition, there were no significant differences between young and old rats, with both groups consuming significantly more of the first 2% solution than the second 2% solution. Therefore, these data suggest that age-related changes may impair the ability to anticipate future rewards.
本研究考察了 7 月龄和 26 月龄 Fischer 344/Brown Norway 大鼠对未来奖励的预期。将年轻和年老的大鼠随机分为两组，并分配到以下两种条件之一。在对照条件下，将大鼠给予含有 2%蔗糖的水溶液 3 分钟，随后立即给予含有 32%蔗糖的水溶液 3 分钟。在无对照条件下，将大鼠给予含有 2%蔗糖的水溶液 3 分钟，随后立即给予含有 2%蔗糖的水溶液 3 分钟。在对照条件下，10 天的测试中，年轻大鼠明显减少了对较不受欢迎的 2%蔗糖溶液的摄入，而老年大鼠则增加了对 2%蔗糖溶液的摄入。在 10 天的测试期内，与老年大鼠相比，年轻大鼠对首选的 32%蔗糖溶液的摄入量显著增加，除了第 8-10 天，两组之间的摄入量没有差异。在无对照条件下，年轻和老年大鼠之间没有显著差异，两组大鼠都明显更多地摄入了第一个 2%溶液，而第二个 2%溶液则摄入较少。因此，这些数据表明，与年龄相关的变化可能会损害对未来奖励的预期能力。
