Sclafani Anthony, Ackroff Karen
Department of Psychology, Brooklyn College and the Graduate School, The City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210-2889, USA.
Physiol Behav. 2003 Sep;79(4-5):663-70. doi: 10.1016/s0031-9384(03)00143-4.
Progressive ratio (PR) schedules, which require increasing numbers of responses for successive reinforcements, are widely used to measure the reward value of foods, fluids, and drugs in operant lever-pressing tasks. The present study evaluated a PR operant licking task as a measure of sweet taste reward. In Experiment 1, food deprived rats were offered sucrose to drink on PR lick or fixed ratio (FR) lick schedules (30 min/day). In Experiment 2, nondeprived rats were offered sucrose to drink on PR or FR schedules and free access to water and food 23 h/day. In both experiments, the FR rats increased and then decreased their sucrose solution intake as concentration increased from 1% to 32% or 64%. The PR rats, in contrast, showed a near-linear increase in sucrose solution intake, lick rates, and break points (highest ratio completed) as a function of sucrose concentration. The PR rats drank less sucrose than did the FR rats although they emitted more total licks at the highest concentration tested. These results are similar to those reported with PR lever-pressing tasks. Thus, PR operant licking, which requires minimal training and equipment, is a useful alternate measure of fluid reward in rodents.
渐进比率（PR）程序要求为连续强化增加反应次数，广泛用于在操作性杠杆按压任务中测量食物、液体和药物的奖励价值。本研究评估了PR操作性舔舐任务作为甜味奖励的一种测量方法。在实验1中，对食物剥夺的大鼠按照PR舔舐或固定比率（FR）舔舐程序提供蔗糖饮用（每天30分钟）。在实验2中，对未剥夺的大鼠按照PR或FR程序提供蔗糖饮用，并允许它们每天23小时自由获取水和食物。在两个实验中，随着蔗糖浓度从1%增加到32%或64%，FR组大鼠的蔗糖溶液摄入量先增加后减少。相比之下，PR组大鼠的蔗糖溶液摄入量、舔舐速率和断点（完成的最高比率）随蔗糖浓度呈近乎线性的增加。尽管在测试的最高浓度下PR组大鼠发出的总舔舐次数更多，但它们饮用的蔗糖比FR组大鼠少。这些结果与PR杠杆按压任务的报告结果相似。因此，PR操作性舔舐所需训练和设备最少，是啮齿动物液体奖励的一种有用替代测量方法。
