Neural correlates of the proximity and quantity of anticipated food rewards in the ventral striatum of domestic chicks
Neural correlates of the proximity and quantity of anticipated food rewards in the ventral striatum of domestic chicks
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DOI：
10.1111/j.1460-9568.2005.04311.x
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发表时间：
2005-09-01
影响因子：
3.4
通讯作者：
Matsushima, T
中科院分区：
文献类型：
--
作者：
Izawa, EI;Aoki, N;Matsushima, T
为了确定评估和选择的神经认知基础，我们分析了自由行为的小鸡腹侧纹状体中预期食物奖励的神经相关性。一周大的小鸡被训练用四种颜色线索（红、黄、绿、蓝）辨别颜色，每一种线索都与不同的食物奖励有关。选择一个红色的珠子会立即得到大量的食物奖励，选择一个黄色的珠子会立即得到少量的食物奖励，选择一个绿色的珠子会得到大量的食物奖励。我们选择了那些一直选择大而直接的食物奖励（红色胜过黄色，红色胜过绿色）的小鸡，它们对食物的接近程度高于食物奖励的大小（黄色胜过绿色）。在这些小鸡腹侧纹状体记录的47个神经元中，有20个神经元选择性地对与食物奖励相关的线索表现出线索周期反应。这20个神经元中有5个在提示期间根据预期的奖励延迟做出不同的反应，因此被认为是对奖励的接近程度进行编码。此外，另外三个神经元对奖励的数量做出反应。此外，在术后延迟期，这20个神经元中的许多都表现出与食物奖励的接近或存在有关的奖励相关活动。因此，我们提出，在腹侧纹状体损伤后观察到的冲动选择和行为坚持可能分别是由于提示期和延迟期对奖励的预期受损。
To identify the neuro-cognitive substrates of valuation and choice, we analysed the neural correlates of anticipated food rewards in the ventral striatum of freely behaving chicks. One-week-old chicks were trained in a color-discrimination task using four color cues (red, yellow, green and blue), each of which was associated with a different food reward. Choosing a red bead was immediately rewarded with a large amount of food, choosing a yellow bead resulted in an immediate-small food reward, and choosing a green bead resulted in a late-large food reward. We selected chicks that consistently chose a large and immediate food reward (red over yellow, and red over green), with the proximity of the food valued higher than the size of the food reward (yellow over green). Of the 47 neurons recorded from the ventral striatum of these chicks, 20 neurons selectively showed cue-period responses to cues associated with food rewards. Five of these 20 neurons responded differentially during the cue period according to the expected delay to reward, and were thus assumed to code for the proximity of the reward. Additionally, three other neurons responded to the quantity of the reward. Furthermore, in the post-operant delay period, many of these 20 neurons showed reward-related activities that were linked to the proximity or presence of the food reward. We therefore propose that impulsive choice and behavioral perseveration observed after lesions of the ventral striatum could be due to impaired anticipation of rewards in the cue and delay periods, respectively.