Astrand Elaine, Ibos Guilhem, Duhamel Jean-René, Ben Hamed Suliann
Centre de Neuroscience Cognitive, CNRS UMR 5229, Université Claude Bernard Lyon I, 69675 Bron cedex, France.
Centre de Neuroscience Cognitive, CNRS UMR 5229, Université Claude Bernard Lyon I, 69675 Bron cedex, France
J Neurosci. 2015 Feb 18;35(7):3174-89. doi: 10.1523/JNEUROSCI.2370-14.2015.
Despite an ever growing knowledge on how parietal and prefrontal neurons encode low-level spatial and color information or higher-level information, such as spatial attention, an understanding of how these cortical regions process neuronal information at the population level is still missing. A simple assumption would be that the function and temporal response profiles of these neuronal populations match that of its constituting individual cells. However, several recent studies suggest that this is not necessarily the case and that the single-cell approach overlooks dynamic changes in how information is distributed over the neuronal population. Here, we use a time-resolved population pattern analysis to explore how spatial position, spatial attention and color information are differentially encoded and maintained in the macaque monkey prefrontal (frontal eye fields) and parietal cortex (lateral intraparietal area). Overall, our work brings about three novel observations. First, we show that parietal and prefrontal populations operate in two distinct population regimens for the encoding of sensory and cognitive information: a stationary mode and a dynamic mode. Second, we show that the temporal dynamics of a heterogeneous neuronal population brings about complementary information to that of its functional subpopulations. Thus, both need to be investigated in parallel. Last, we show that identifying the neuronal configuration in which a neuronal population encodes given information can serve to reveal this same information in a different context. All together, this work challenges common views on neural coding in the parietofrontal network.
尽管我们对顶叶和前额叶神经元如何编码低级空间和颜色信息或高级信息（如空间注意力）的了解日益增加，但对于这些皮质区域如何在群体水平上处理神经元信息仍缺乏认识。一个简单的假设是，这些神经元群体的功能和时间响应特征与其组成的单个细胞相匹配。然而，最近的几项研究表明情况并非一定如此，单细胞方法忽略了信息在神经元群体中分布方式的动态变化。在这里，我们使用时间分辨群体模式分析来探究空间位置、空间注意力和颜色信息在猕猴前额叶（额叶眼区）和顶叶皮质（侧顶内区）中是如何被差异编码和维持的。总体而言，我们的工作带来了三个新的发现。第一，我们表明顶叶和前额叶群体在编码感觉和认知信息时以两种不同的群体模式运作：静止模式和动态模式。第二，我们表明异质性神经元群体的时间动态为其功能亚群带来了互补信息。因此，两者都需要并行研究。最后，我们表明识别神经元群体编码给定信息的神经元配置有助于在不同背景下揭示相同的信息。总之，这项工作挑战了关于顶额叶网络中神经编码 的普遍观点。
