Meisch Richard A, Gomez Thomas H
Department of Psychiatry and Behavioral Sciences, Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA.
Behav Pharmacol. 2013 Jun;24(3):155-63. doi: 10.1097/FBP.0b013e32836104cd.
Relative reinforcing effects of different ethanol and different cocaine doses were studied under concurrent independent fixed-ratio (FR) schedules and concurrent nonindependent FR schedules with rhesus monkeys. Nonindependent FR schedules differed from independent FR schedules in that responses on either side counted towards the FR requirements of two concurrently presented choices. Thus, responses on the right operandum counted toward completion of both right and left FR schedules and, symmetrically, responses on the left did the same. Nonindependent schedules allow the number of responses per drug delivery to vary considerably, unlike independent schedules, thereby making the number of responses per delivery a sensitive dependent variable. In contrast, standard independent schedules do not allow responses per drug delivery to vary; the required number of responses is an independent variable. Three rhesus monkeys were subjects, and choices between different doses of ethanol or cocaine were studied. Larger doses maintained higher response rates than smaller doses - consistent with previous choice studies. By using nonindependent schedules, however, graded responses per drug delivery and increased switching between sides were obtained, providing additional data and useful measures of choice.
在恒河猴身上，采用并发独立固定比率（FR）时间表以及并发非独立FR时间表，研究了不同剂量乙醇和不同剂量可卡因的相对强化作用。非独立FR时间表与独立FR时间表的不同之处在于，两侧的反应都计入同时呈现的两种选择的FR要求。因此，右侧操作反应既计入右侧FR时间表的完成，也计入左侧FR时间表的完成，对称地，左侧反应也是如此。与独立时间表不同，非独立时间表允许每次给药的反应次数有很大差异，从而使每次给药的反应次数成为一个敏感的因变量。相比之下，标准的独立时间表不允许每次给药的反应次数有所变化；所需的反应次数是一个自变量。以三只恒河猴为实验对象，研究了它们在不同剂量乙醇或可卡因之间的选择。与之前的选择研究一致，较大剂量维持的反应率比较小剂量更高。然而，通过使用非独立时间表，获得了每次给药的分级反应以及两侧之间增加的切换，提供了额外的数据和有用的选择度量。
