Excitotoxic lesions of the medial striatum delay extinction of a reinforcement color discrimination operant task in domestic chicks; a functional role of reward anticipation
Excitotoxic lesions of the medial striatum delay extinction of a reinforcement color discrimination operant task in domestic chicks; a functional role of reward anticipation
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DOI：
10.1016/j.cogbrainres.2004.08.001
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发表时间：
2004-12-01
期刊：
影响因子：
--
通讯作者：
Matsushima, T
中科院分区：
文献类型：
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作者：
Ichikawa, Y;Izawa, EI;Matsushima, T
为了揭示纹状体的功能作用，我们研究了在食物强化辨色操作任务中，兴奋性毒性损伤对双侧内侧纹状体（mSt）和核（Ac）的影响。以食物奖励作为强化，训练1周龄的雏鸡选择性地啄红色和黄色珠子（S+），而不啄蓝色珠子（S-）。然后，这些小鸡要么接受损伤，要么接受假手术，并在灭绝训练课程中进行测试，在此期间，黄色被证明是无回报的（S-），而红色和蓝色保持不变。为了进一步研究对术后非工具行为的影响，我们还测量了“等待时间”，在此期间，小鸡在啄食黄色后停留在空喂食器上。尽管受损雏鸡在无奖励的黄色试验中表现出明显更高的错误率，但它们的术后等待时间逐渐减少，与假对照组相似。此外，患病的雏鸟比对照组等待的时间明显更长，甚至从第一个灭绝块开始。在蓝色的试验中，受伤的和假的小鸡都一直避免啄食，这表明延迟灭绝不是由于啄食的普遍解除抑制。同样，在新的训练课程中没有发现任何影响，这表明这些损伤对习得的操作人员的消失有选择性的影响。这些结果表明，mSt/Ac中基于记忆的奖励预期的神经表征可能导致消退所需的预期误差。(C) 2004 Elsevier B.V.版权所有
To reveal the functional roles of the striatum, we examined the effects of excitotoxic lesions to the bilateral medial striatum (mSt) and nucleus (Ac) in a food reinforcement color discrimination operant task. With a food reward as reinforcement, 1-week-old domestic chicks were trained to peck selectively at red and yellow beads (S+) and not to peck at a blue bead (S-). Those chicks then received either lesions or sham operations and were tested in extinction training sessions, during which yellow turned out to be nonrewarding (S-), whereas red and blue remained unchanged. To further examine the effects on postoperant noninstrumental aspects of behavior, we also measured the "waiting time", during which chicks stayed at the empty feeder after pecking at yellow. Although the lesioned chicks showed significantly higher error rates in the nonrewarding yellow trials, their postoperant waiting time gradually decreased similarly to the sham controls. Furthermore, the lesioned chicks waited significantly longer than the controls, even from the first extinction block. In the blue trials, both lesioned and sham chicks consistently refrained from pecking, indicating that the delayed extinction was not due to a general disinhibition of pecking. Similarly, no effects were found in the novel training sessions, suggesting that the lesions had selective effects on the extinction of a learned operant. These results suggest that a neural representation of memory-based reward anticipation in the mSt/Ac could contribute to the anticipation error required for extinction. (C) 2004 Elsevier B.V. All rights reserved.