Dopamine Regulates Two Classes of Primate Prefrontal Neurons That Represent Sensory Signals
Dopamine Regulates Two Classes of Primate Prefrontal Neurons That Represent Sensory Signals
复制标题
DOI：
10.1523/jneurosci.0210-13.2013
复制
发表时间：
2013-08-21
影响因子：
5.3
通讯作者：
Nieder, Andreas
中科院分区：
文献类型：
--
作者：
Jacob, Simon N.;Ott, Torben;Nieder, Andreas
侧前额叶皮层（PFC）是高级认知处理的中枢，受中脑多巴胺（DA）神经元的强烈调节。在短期记忆的背景下，细胞机制已经得到了全面的研究，但关于DA如何调节PFC的感觉输入，这些输入在这种记忆活动之前和之后是如何产生的，我们知之甚少。通过为接收信号准备受体皮层回路，DA可能是下游认知处理的一个强大决定因素。在这里，我们测试了前额叶DA调节感知决策所需的感觉信号表征的假设。在恒河猴中，我们训练它们在不同对比度水平下报告视觉刺激的存在或不存在，同时记录细胞外单单位活动，并通过微离子导入将DA应用于神经元附近。我们发现前额叶神经元的DA调节不是统一的，而是针对特定的神经元类别量身定制的。在一个神经元群体中，DA抑制活动具有较高的时间精度，但保留了信噪比。这组神经元具有较短的视觉反应潜伏期，包括所有记录的窄尖峰，假定的中间神经元。在不同的人群中，DA通过降低反应变异性增加兴奋性和增强信噪比。这些神经元具有较长的视觉反应潜伏期，并且完全由宽尖峰，假定的锥体神经元组成。通过将感觉输入门控到PFC并随后加强感觉信号的表征，DA可能在塑造PFC如何启动响应感觉环境变化的适当行为方面发挥重要作用。
The lateral prefrontal cortex (PFC), a hub of higher-level cognitive processing, is strongly modulated by midbrain dopamine (DA) neurons. The cellular mechanisms have been comprehensively studied in the context of short-term memory, but little is known about how DA regulates sensory inputs to PFC that precede and give rise to such memory activity. By preparing recipient cortical circuits for incoming signals, DA could be a powerful determinant of downstream cognitive processing. Here, we tested the hypothesis that prefrontal DA regulates the representation of sensory signals that are required for perceptual decisions. In rhesus monkeys trained to report the presence or absence of visual stimuli at varying levels of contrast, we simultaneously recorded extracellular single-unit activity and applied DA to the immediate vicinity of the neurons by micro-iontophoresis. We found that DA modulation of prefrontal neurons is not uniform but tailored to specialized neuronal classes. In one population of neurons, DA suppressed activity with high temporal precision but preserved signal/noise ratio. Neurons in this group had short visual response latencies and comprised all recorded narrow-spiking, putative interneurons. In a distinct population, DA increased excitability and enhanced signal/noise ratio by reducing response variability. These neurons had longer visual response latencies and were composed exclusively of broad-spiking, putative pyramidal neurons. By gating sensory inputs to PFC and subsequently strengthening the representation of sensory signals, DA might play an important role in shaping how the PFC initiates appropriate behavior in response to changes in the sensory environment.