Wenger G.R., McMillan D.E., Moore E., Williamson A.P.
Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA.
Behav Pharmacol. 1995 Jun;6(4):297-310.
Pigeons were trained to discriminate the length of a delay period (3s vs. 10s). Under control conditions, pigeons were able to discriminate between the two delay period lengths with a high degree of accuracy (>90%). When delays of 1, 3, 5, 7, 9 and 11s were randomly presented, the percentage of responses appropriate to the 10s delay increased as a function of increasing delay length. Dose-response curves determined for a series of drugs of abuse showed that pentobarbital, diazepam and phencyclidine displayed the greatest efficacy in disrupting the discrimination. The decrease in accuracy was a function of both a decrease in the ability of the pigeon to discriminate the passage of time, and the expression of a drug-induced red color bias. When the stimulus colors were changed, these drugs still decreased accuracy of the discrimination without any evidence of a color bias. Morphine disrupted the discrimination at doses which produced marked response suppression; there was no evidence of a drug-induced color bias. Delta(9)-THC failed to produce any significant effect on the discrimination. d-amphetamine and cocaine initially had no effect; however, upon subsequent determinations and when the stimulus colors were changed during the last part of the experiment, they did disrupt discrimination performance. These results show that drugs of abuse have differential effects on temporal discrimination, with some drugs affecting temporal discrimination at doses that do not suppress responding, some affecting the discrimination at doses that decrease response rates, and others that do not appear to affect temporal discrimination. Only sedative/hypnotic drugs disrupted temporal discrimination in part by producing a red-color bias.
鸽子经过训练以辨别延迟期的长度（3秒与10秒）。在对照条件下，鸽子能够以高度的准确性（>90%）区分这两种延迟期长度。当随机呈现1、3、5、7、9和11秒的延迟时，与10秒延迟相对应的反应百分比随着延迟长度的增加而增加。对一系列滥用药物测定的剂量-反应曲线表明，戊巴比妥、地西泮和苯环己哌啶在扰乱辨别方面显示出最大的效力。准确性的降低既是鸽子辨别时间流逝能力下降的函数，也是药物诱导的红色偏向表达的函数。当刺激颜色改变时，这些药物仍然会降低辨别准确性，且没有任何颜色偏向的证据。吗啡在产生明显反应抑制的剂量下扰乱了辨别；没有药物诱导的颜色偏向的证据。δ-9-四氢大麻酚未能对辨别产生任何显著影响。右旋苯丙胺和可卡因最初没有影响；然而，在随后的测定中以及当在实验的最后部分改变刺激颜色时，它们确实扰乱了辨别表现。这些结果表明，滥用药物对时间辨别有不同的影响，一些药物在不抑制反应的剂量下影响时间辨别，一些在降低反应率的剂量下影响辨别，而另一些似乎不影响时间辨别。只有镇静/催眠药物部分地通过产生红色偏向扰乱了时间辨别。
