Gobin Christina, Schwendt Marek
Department of Psychology, College of Liberal Arts & Sciences University of Florida, Gainesville, USA.
J Addict Prev. 2017 Apr;5(1). doi: 10.13188/2330-2178.1000035. Epub 2017 Apr 27.
Cocaine use disorder is characterized not only by the high rate of relapse, but also by deficits in cognition and prefrontal cortical function. Still, the relationship between cognitive impairment and cocaine-seeking remains poorly understood. The current study used a rodent model to determine the effects of extended access cocaine self-administration on cognitive performance in a prefrontal cortex-dependent delayed match-to-sample/non-match-to-sample (DMS/DNMS) task. Further, this study sought to investigate how post-cocaine changes in cognitive performance correlate with cue/context-induced cocaine-seeking following a prolonged period of abstinence. Animals were trained to self-administer cocaine during 6 daily 1 hour-long sessions followed by 12 days of extended, 6 hour-long access. The extended access cocaine rats exhibited robust self-administration behavior and escalation of cocaine intake. Next, DMS/DNMS task was used to evaluate working memory capacity and reversal learning performance over a range of 0 - 30 s delays. Although this study failed to detect a major cognitive impairment, extended access to cocaine resulted in the persistent working memory/DMS deficit at a moderate cognitive load (10 s delay). There were no changes in the reversal learning/DNMS performance. It is likely that the parameters of the DMS/DNMS task, as used in the current study, exceeded acquisition capacity of rats thus obscuring cocaine effects at longer delays. Finally, rats showed a robust relapse of context/cue-elicited cocaine-seeking following the 45 - day abstinence. However, the intensity of cocaine-seeking did not correlate with the deficit in the DMS task. In conclusion, future studies must re-evaluate whether a more robust relationship between post-cocaine cognitive performance and cocaine-seeking can be detected under adjusted DMS/DNMS conditions.
可卡因使用障碍不仅以高复发率为特征，还伴有认知和前额叶皮质功能缺陷。尽管如此，认知障碍与觅可卡因行为之间的关系仍未得到充分理解。当前研究使用啮齿动物模型来确定延长获取可卡因自我给药对前额叶皮质依赖的延迟匹配样本/非匹配样本（DMS/DNMS）任务中认知表现的影响。此外，本研究旨在调查在长时间禁欲后，可卡因使用后认知表现的变化与线索/情境诱发的觅可卡因行为之间的相关性。动物在每天6次、每次1小时的时间段内接受可卡因自我给药训练，随后是12天的延长获取期，每次6小时。延长获取可卡因的大鼠表现出强烈的自我给药行为和可卡因摄入量的增加。接下来，使用DMS/DNMS任务在0 - 30秒的延迟范围内评估工作记忆能力和逆向学习表现。尽管本研究未能检测到主要的认知障碍，但延长获取可卡因导致在中等认知负荷（10秒延迟）下持续存在工作记忆/DMS缺陷。逆向学习/DNMS表现没有变化。本研究中使用的DMS/DNMS任务参数可能超过了大鼠的获取能力，从而掩盖了较长延迟下可卡因的作用。最后，在45天禁欲后，大鼠表现出强烈的情境/线索诱发的觅可卡因行为复发。然而，觅可卡因行为的强度与DMS任务中的缺陷无关。总之，未来的研究必须重新评估在调整后的DMS/DNMS条件下，是否能检测到可卡因使用后认知表现与觅可卡因行为之间更强有力的关系。
