Bizarro L, Stolerman I P
Section of Behavioural Pharmacology, Institute of Psychiatry P049, King's College London, De Crespigny Park, London, SE5 8AF, UK.
Psychopharmacology (Berl). 2003 Nov;170(3):271-277. doi: 10.1007/s00213-003-1543-6. Epub 2003 Sep 2.
The effects of drugs on performance of tasks used to assess attention might be confounded with changes in motivation. Few studies have investigated the role of motivational factors in such situations.
To determine how changes in motivation for food influence performance of the 5-choice serial reaction time task and whether the effects of nicotine and amphetamine can be explained by motivational changes.
Male hooded Lister rats were trained to respond to a 1-s light stimulus presented randomly in one of five apertures in order to obtain food reinforcers. For three groups of rats (n=9-10), access to food was restricted to maintain body weights at 80, 90 or 95% of control weights. Saline and nicotine (0.025-0.2 mg/kg) were tested in each group, with and without pre-feeding (5 g). In a second experiment, saline and amphetamine (0.03-0.9 mg/kg s.c.) were tested without pre-feeding.
High levels of motivation for food were associated with increases in anticipatory responses, fewer omission errors, shorter response latencies and completion of more trials, without change in accuracy. Nicotine, but not amphetamine, increased accuracy and the number of trials completed; whereas amphetamine, but not nicotine, increased omission errors. Both drugs decreased anticipatory responding at the largest doses tested. There were few interactions of motivational level with drug effects.
The improvements in performance produced by nicotine did not resemble the effect of increased motivation, but some effects of amphetamine resembled those of reducing the level of motivation for food. Motivational levels did not confound assessments of the attentional effects of the drugs in terms of response accuracy.
药物对用于评估注意力的任务表现的影响可能会与动机变化相混淆。很少有研究调查动机因素在这种情况下的作用。
确定食物动机的变化如何影响五选择连续反应时任务的表现，以及尼古丁和苯丙胺的作用是否可以用动机变化来解释。
对雄性带帽利斯特大鼠进行训练，使其对在五个孔之一中随机呈现的1秒光刺激做出反应，以获得食物强化物。对于三组大鼠（n = 9 - 10），限制食物获取以将体重维持在对照体重的80%、90%或95%。在每组中测试生理盐水和尼古丁（0.025 - 0.2毫克/千克），有或没有预喂食（5克）。在第二个实验中，测试生理盐水和苯丙胺（0.03 - 0.9毫克/千克皮下注射）且没有预喂食。
对食物的高动机水平与预期反应增加、遗漏错误减少、反应潜伏期缩短以及完成更多试验相关，准确性没有变化。尼古丁增加了准确性和完成的试验次数，但苯丙胺没有；而苯丙胺增加了遗漏错误，但尼古丁没有。在测试的最大剂量下，两种药物都减少了预期反应。动机水平与药物效应之间几乎没有相互作用。
尼古丁产生的表现改善与动机增加的效果不同，但苯丙胺的一些效果类似于降低对食物的动机水平的效果。就反应准确性而言，动机水平并未混淆对药物注意力效应的评估。
