Pinkston Jonathan W, Madden Gregory J, Fowler Stephen C
Schiefelbusch Institute for Life Span Studies, Dole HDC, Lawrence, Kansas 66049, USA.
Behav Pharmacol. 2008 Jul;19(4):347-52. doi: 10.1097/FBP.0b013e32830990ac.
This experiment was concerned with the role of the environment in the production and form of apomorphine-induced pecking of pigeons. Earlier literature has suggested that the pecking occurs even when pigeons are placed in complete darkness, but there are no systematic or quantitative reports of such pecking. Six pigeons were tested with doses of 0.1, 0.3, and 1.0 mg/kg apomorphine. Tests were made in conditions of white and infrared light. The apparatus used novel force transduction measures that provided for both the detection of a peck as well as its peak forcefulness. At the lowest dose tested, apomorphine elicited pecking when the pigeon was placed in white light, but not when the dose was examined under infrared lighting. As the dose increased, however, pecking was observed regardless of lighting condition. No consistent differences were found in forcefulness of pecking as a function of lighting condition or dose. Though response output was seemingly unaffected by the lighting condition at higher doses, videotaped analysis revealed important changes in the formal characteristics of pecking. In white light, apomorphine elicited pecking at stimuli in the chamber (e.g. screw heads or the pigeon's own toes), whereas in infrared light pecking was directed at the floor directly in front of the pigeon. Such differences may be attributable to shifts in control to other stimulus modalities when vision is limited. Additionally, apomorphine may have direct effects on retinal dopamine function modulating the expression of pecking in the dark.
本实验关注环境在阿扑吗啡诱导鸽子啄食行为的产生及形式方面所起的作用。早期文献表明，即使将鸽子置于完全黑暗的环境中，啄食行为仍会发生，但尚无关于此类啄食行为的系统或定量报告。对6只鸽子分别注射0.1、0.3和1.0毫克/千克剂量的阿扑吗啡进行测试。测试在白光和红外光条件下进行。该实验装置采用了新型力传导测量方法，既能检测到啄食行为，又能测量其峰值力度。在测试的最低剂量下，当鸽子处于白光环境中时，阿扑吗啡会引发啄食行为，但在红外光照射下检测该剂量时则不会。然而，随着剂量增加，无论光照条件如何，均观察到啄食行为。未发现啄食力度在光照条件或剂量方面存在一致差异。尽管在较高剂量下反应输出似乎不受光照条件影响，但录像分析显示啄食行为的形式特征发生了重要变化。在白光下，阿扑吗啡会使鸽子对鸽笼内的刺激物（如螺丝头或鸽子自己的脚趾）产生啄食行为，而在红外光下，啄食行为则直接针对鸽子正前方的地面。此类差异可能归因于视觉受限情况下控制转向其他刺激模式。此外，阿扑吗啡可能对视网膜多巴胺功能有直接影响，从而调节黑暗环境中啄食行为的表现。
