Valles Rodrigo, Rocha Angelica, Nation Jack R
Department of Psychology, Texas A&M University, College Station, 77843, USA.
Exp Clin Psychopharmacol. 2006 May;14(2):245-53. doi: 10.1037/1064-1297.14.2.245.
Partial reinforcement is known to increase resistance to extinction (Rn) relative to training with continuous reinforcement. This phenomenon, referred to as the partial reinforcement extinction effect, is one of the most robust in learning and conditioning studies. Experiment 1 investigated manipulations known to affect the partial reinforcement extinction effect and determined their possible relevance for drug use patterns. Male rats received intravenous cocaine self-administration training under partial reinforcement (FR-10) training or continuous reinforcement (FR-1) conditions with either a low (0.25 mg/kg infusion) or a high cocaine dose (1.00 mg/kg infusion). Animals were placed on an extinction (recurrent nonreward) schedule for 10 days (1-hr sessions) prior to being tested for cue-induced reinstatement (single 2-hr session). Experiment 2 involved acquisition of cocaine self-administration under FR-1 conditions of short training (15 days) or extended training (30 days) with a low dose (0.25 mg/kg infusion) or a medium dose (0.50 mg/kg infusion) of cocaine reward prior to extinction or reinstatement. Experiment 1 showed that rats trained with FR-10-high dose outcomes exhibited greater Rn than the remaining groups. Additionally, FR-10-high dose and FR-10-low dose rats were more likely to return to active drug seeking during the reinstatement test. In Experiment 2, rats trained under FR-1-medium dose conditions were more persistent during extinction following short acquisition training than comparable rats experiencing extended acquisition training. The reinstatement test was conducted following extinction, in which it was observed that overtraining under FR-1-medium dose reward schedules resulted in a decrease in the tendency to return to active drug seeking.
相对于连续强化训练，部分强化已知会增加消退抗性（Rn）。这种现象被称为部分强化消退效应，是学习和条件反射研究中最稳定的现象之一。实验1研究了已知会影响部分强化消退效应的操作，并确定了它们与药物使用模式的可能关联。雄性大鼠在部分强化（FR-10）训练或连续强化（FR-1）条件下接受静脉注射可卡因自我给药训练，可卡因剂量分为低剂量（0.25毫克/千克注射量）或高剂量（1.00毫克/千克注射量）。在进行线索诱导复吸测试（单次2小时测试）之前，将动物置于消退（反复无奖励）程序中10天（每次1小时）。实验2涉及在FR-1条件下，用低剂量（0.25毫克/千克注射量）或中等剂量（0.50毫克/千克注射量）的可卡因奖励进行短期训练（15天）或长期训练（30天）后，进行可卡因自我给药的习得，然后进行消退或复吸测试。实验1表明，接受FR-10高剂量结果训练的大鼠比其他组表现出更大的Rn。此外，FR-10高剂量组和FR-10低剂量组的大鼠在复吸测试中更有可能恢复积极的药物寻求行为。在实验2中，在短期习得训练后，接受FR-1中等剂量条件训练的大鼠在消退过程中比经历长期习得训练的同类大鼠更持久。在消退后进行了复吸测试，结果观察到，在FR-1中等剂量奖励程序下的过度训练导致恢复积极药物寻求行为的倾向降低。
