Grilly D M, Nocjar C
Psychology Department, Cleveland State University, OH 44115.
Pharmacol Biochem Behav. 1990 Dec;37(4):643-8. doi: 10.1016/0091-3057(90)90540-x.
In two experiments rats were food-reinforced for pressing one of two levers in an operant chamber, with the correct lever being indicated by the position of a briefly illuminated light. In Experiment 1 the levers were always in the chamber, whereas in Experiment 2 the levers were inserted into the chamber immediately after cue light termination and withdrawn immediately after a choice response. The rats were tested under four conditions: after an injection (SC) of saline or 2.5 mg/kg cocaine and with delay of reinforcement (DOR) of either 0 or 8 s. In both experiments, cocaine enhanced accuracy under the 0-s DOR condition. However, in neither experiment was there evidence of facilitation with cocaine under 8-s DOR, which by itself increased choice latencies and decreased accuracy when choice latencies exceeded 0.5 s. These results indicate that cocaine may only enhance performance in vigilance tasks under constrained conditions, e.g., those that require minimal levels of information processing.
在两项实验中，大鼠在操作箱中按压两个杠杆之一可获得食物强化，正确的杠杆由短暂亮起的灯光位置指示。在实验1中，杠杆始终在操作箱内，而在实验2中，杠杆在提示光熄灭后立即插入操作箱，并在做出选择反应后立即取出。大鼠在四种条件下接受测试：皮下注射生理盐水或2.5毫克/千克可卡因后，以及强化延迟（DOR）为0或8秒时。在两项实验中，可卡因在0秒DOR条件下提高了准确性。然而，在两项实验中，均未发现可卡因在8秒DOR条件下有促进作用，当选择潜伏期超过0.5秒时，8秒DOR本身会增加选择潜伏期并降低准确性。这些结果表明，可卡因可能仅在受限条件下，例如那些需要最低信息处理水平的条件下，才会提高警觉任务中的表现。
