Walker D J, Branch M N
Department of Psychology, University of Florida, Gainesville 32611, USA.
J Exp Anal Behav. 1996 Mar;65(2):375-88. doi: 10.1901/jeab.1996.65-375.
Key pecking by 4 pigeons was maintained by a multiple schedule consisting of two variable-interval 60-s schedules wherein each food presentation followed a nonresetting 27-s delay that was either briefly signaled at its outset or completely signaled. Brief-signal duration was adjusted so that response rates maintained by the briefly and completely signaled delays of reinforcement were similar. In general, acute administration of small to intermediate doses (0.3 to 3.0 mg/kg) of cocaine produced either small increases in response rates in both components or no change, and larger doses (5.6 to 13.0 mg/kg) decreased response rates. Chronic (i.e., daily) cocaine administration (10.0 mg/kg) resulted in tolerance to the rate-decreasing effects in both components. Cocaine's effects were generally similar whether delays were completely or briefly signaled. Discontinuation of cocaine administration and subsequent removal of the delay signals also had similar effects in both components of the multiple schedule. Taken together, these results are consistent with the view that the two types of delay signals were equally effective in maintaining responding during the variable-interval schedules.
4只鸽子的按键行为通过一个多重程序维持，该程序由两个60秒的可变间隔程序组成，其中每次食物呈现之前有一个27秒的非重置延迟，这个延迟在开始时要么有短暂信号提示，要么有完整信号提示。调整短暂信号的持续时间，以使由短暂和完整信号提示的强化延迟所维持的反应率相似。一般来说，急性给予小到中等剂量（0.3至3.0毫克/千克）的可卡因，在两个成分中要么使反应率小幅增加，要么没有变化，而较大剂量（5.6至13.0毫克/千克）则会降低反应率。慢性（即每日）给予可卡因（10.0毫克/千克）导致对两个成分中反应率降低效应产生耐受性。无论延迟是有完整信号还是短暂信号提示，可卡因的效应通常相似。停止给予可卡因并随后去除延迟信号，在多重程序的两个成分中也有相似的效果。综上所述，这些结果与以下观点一致，即在可变间隔程序中，这两种类型的延迟信号在维持反应方面同样有效。
