The HIV transgenic (HIVtg) rat is a commonly used animal model of chronic HIV infection that exhibits a wide range of cognitive deficits. To date, relatively little work has been conducted on these rats’ capacity for reversal learning, an assay of executive function and cognitive flexibility used in humans. The present study sought to determine the impact of HIV genotype on probabilistic reversal learning, effortful motivation, and spontaneous locomotion/exploration in rats. Male (n = 8) and female (n = 8) HIVtg rats and wildtype (WT) controls were utilized. Cognitive flexibility was assessed via the Probabilistic Reversal Learning Task (PRLT), which reinforced responses to two stimuli on differential probabilistic schedules that periodically reversed. Effortful motivation and locomotor/exploratory behavior were assessed via the Progressive Ratio Breakpoint Task (PRBT) and the Behavioral Pattern Monitor (BPM), respectively. Regardless of sex, HIVtg rats required fewer trials to ascertain initial PRLT reward schedules than WT rats, and completed the same number of reversals. Secondary behaviors suggested that HIVtg PRLT performance was facilitated by a speed-accuracy tradeoff strategy. No main or interactive effects of genotype were observed in the PRBT or BPM. Relative to WT controls, HIVtg rats exhibited superior probabilistic reinforcement learning. Reversal learning was unaffected by HIV genotype, as was effortful motivation and exploratory behavior. These findings contrast with previous characterizations of the HIVtg rat, thus indicating a nuanced cognitive profile that is dependent upon such task specifications as within- versus between-session assessment and probabilistic versus deterministic reward schedules.

HIV 转基因 (HIVtg) 大鼠是一种常用的慢性 HIV 感染动物模型，表现出广泛的认知缺陷。迄今为止，对这些老鼠的逆转学习能力进行的研究相对较少，这是一种用于人类执行功能和认知灵活性的测定。本研究旨在确定 HIV 基因型对大鼠概率逆转学习、努力动机和自发运动/探索的影响。使用雄性 (n = 8) 和雌性 (n = 8) HIVtg 大鼠和野生型 (WT) 对照。认知灵活性是通过概率逆转学习任务 (PRLT) 评估的，该任务加强了对周期性逆转的差异概率时间表上的两种刺激的反应。努力动机和运动/探索行为分别通过渐进比率断点任务 (PRBT) 和行为模式监测器 (BPM) 进行评估。无论性别如何，HIVtg 大鼠比 WT 大鼠需要更少的试验来确定初始 PRLT 奖励计划，并完成相同数量的逆转。次要行为表明 HIVtg PRLT 性能受到速度-准确性权衡策略的促进。在 PRBT 或 BPM 中没有观察到基因型的主要或交互影响。相对于 WT 控件，HIVtg 大鼠表现出优越的概率强化学习。逆转学习不受 HIV 基因型的影响，努力的动机和探索行为也是如此。这些发现与之前对 HIVtg 大鼠的特征形成对比，