Striatal dopamine release in the rat during a cued lever-press task for food reward and the development of changes over time measured using high-speed voltammetry
Striatal dopamine release in the rat during a cued lever-press task for food reward and the development of changes over time measured using high-speed voltammetry
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DOI：
10.1007/s00221-005-2345-3
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发表时间：
2005-09-01
影响因子：
2
通讯作者：
Nakazato, T
中科院分区：
文献类型：
--
作者：
Nakazato, T
灵长类动物的黑质多巴胺神经元活动被认为与预测奖励传递的错误有关。大鼠伏隔核中多巴胺的释放已被证明与药物/食物寻求行为有关。目前尚不清楚纹状体中多巴胺的释放如何对应于奖励性提示任务的许多不同步骤（例如识别提示、执行行为、预期奖励、接收奖励），以及多巴胺释放如何随着任务绩效的提高而随着时间的推移而变化。为了研究奖励、提示任务期间多巴胺的释放以及多巴胺释放随时间变化的发展，使用高速体内伏安法，每周几天测量奖励、提示杠杆按压任务期间细胞外纹状体多巴胺浓度的变化，持续 5 个月。老鼠被训练在听到声音后按下杠杆以获得食物奖励。随着训练的继续，压杆的反应时间逐渐减少。在最初的 6 天熟悉期（其中动物了解到按下杠杆会产生食物）以及 5 周的手术、恢复和电极准备期后，测量任务执行过程中前纹状体（腹侧部分）多巴胺浓度的变化。在任务执行过程中，多巴胺浓度在提示后开始增加，在按下杠杆时达到峰值，并在按下杠杆后 1-2 秒恢复到基础水平。在 5 个月的测试中观察到了多巴胺浓度的这种变化模式，峰值多巴胺浓度稳定增加，直到第 7 周达到峰值，此时任务表现尚未从第 2 周显着改善。到第 13 周，任务表现显着改善，峰值多巴胺浓度开始消退。因此，当任务尚未完善时，提示后多巴胺浓度的增加最高，并在学习过程结束时减弱。结论是，在提示性杠杆按压任务期间纹状体多巴胺的释放与条件的新颖性相关。
Substantia nigra dopamine neuronal activity in the primate is thought to be related to the error in predicting reward delivery. Dopamine release in rat nucleus accumbens has been shown to increase in relation to drug/food-seeking behaviour. It is not known how the release of dopamine in the striatum corresponds to the many distinct steps of a rewarded, cued task (e.g. recognizing the cue, executing the behaviour, anticipating the reward, receiving the reward) and how dopamine release then changes over time as task performance improves. To investigate dopamine release during a rewarded, cued task and the development of changes in dopamine release over time, changes in extracellular striatal dopamine concentration during a rewarded, cued lever-press task were measured a few days every week for 5 months using high-speed in vivo voltammetry. Rats were trained to press a lever after a tone to obtain a food reward. The reaction time for the lever press decreased gradually as training continued. Changes in dopamine concentration were measured in the anterior striatum (ventral portion) during the task performance after an initial 6-day familiarization period, in which the animals learned that a lever press yielded food, and a 5-week period for surgery, recovery, and electrode preparation. During the task performance, dopamine concentration started to increase just after the cue, peaked near the time of the lever press, and returned to basal levels 1-2 s after the lever press. This pattern of changes in dopamine concentration was observed over the 5 months of testing, the peak dopamine concentration increasing steadily until peaking at week 7, at which time the task performance had not yet improved significantly from week 2. By week 13, task performance had significantly improved and peak dopamine concentration had begun to subside. Thus, the increase in dopamine concentration after the cue was highest while the task was not yet perfected and subsided toward the end of the learning process. It was concluded that striatal dopamine release during a cued lever-press task is relevant to the novelty of the conditions.