Diversity and homogeneity in responses of midbrain dopamine neurons.
Diversity and homogeneity in responses of midbrain dopamine neurons.
复制标题
DOI：
10.1523/jneurosci.3886-12.2013
复制
发表时间：
2013-03-13
期刊：
影响因子：
--
通讯作者：
Song MR
中科院分区：
文献类型：
--
作者：
Fiorillo CD;Yun SR;Song MR
腹侧中脑的多巴胺神经元被发现发出奖励预测错误的信号，可以介导正强化。尽管在细胞和分子水平上表现出适度的多样性，但对行为动物的反应多样性的分析很少。在这里，我们研究反应的多样性恒河猴的食欲，厌恶，和中性刺激具有相对的动机价值，通过选择任务的测量和控制。首先，与以前的研究一致，我们观察到一个连续的反应变异性和散点图中明显缺乏不同的集群，这表明缺乏统计离散的神经元亚群。其次，我们发现一组“敏感”的神经元往往会受到各种刺激的更强烈的抑制，并被果汁更强烈地激活。第三，发现黑质的“腹侧层”中的神经元具有更大的抑制，并且其中一个子集具有更高的基线放电率和抑制后的晚期“反弹”激活。这些神经元可能属于先前鉴定的多巴胺神经元亚组，其表达高水平的H型阳离子通道，但缺乏钙结合蛋白。第四，神经元进一步吻侧表现出更大的抑制。第五，虽然我们观察到一些神经元对厌恶刺激的微弱激活，但这与它们的厌恶程度无关。总之，我们发现一个多样性的响应特性，分布沿着一个连续，在什么可能是一个单一的功能群体的神经元信号奖励预测错误。
Dopamine neurons of the ventral midbrain have been found to signal a reward prediction error that can mediate positive reinforcement. Despite the demonstration of modest diversity at the cellular and molecular levels, there has been little analysis of response diversity in behaving animals. Here we examine response diversity in rhesus macaques to appetitive, aversive, and neutral stimuli having relative motivational values that were measured and controlled through a choice task. First, consistent with previous studies, we observed a continuum of response variability and an apparent absence of distinct clusters in scatter plots, suggesting a lack of statistically discrete subpopulations of neurons. Second, we found that a group of “sensitive” neurons tend to be more strongly suppressed by a variety of stimuli and to be more strongly activated by juice. Third, neurons in the “ventral tier” of substantia nigra were found to have greater suppression, and a subset of these had higher baseline firing rates and late “rebound” activation after suppression. These neurons could belong to a previously identified subgroup of dopamine neurons that express high levels of H-type cation channels but lack calbindin. Fourth, neurons further rostral exhibited greater suppression. Fifth, although we observed weak activation of some neurons by aversive stimuli, this was not associated with their aversiveness. In conclusion, we find a diversity of response properties, distributed along a continuum, within what may be a single functional population of neurons signaling reward prediction error.