Animal Physiology Unit, Institute of Neurobiology, University of Tübingen, Auf der Morgenstelle 28, 2872076, Tübingen, Germany.
Nat Commun. 2020 Feb 4;11(1):686. doi: 10.1038/s41467-020-14519-2.
Humans' symbolic counting skills are built on a primordial ability to approximately estimate the number of items, or numerosity. To date it is debated whether numerosities presented in categorically different formats, that is as temporal sequences versus spatial arrays, are represented abstractly in the brain. To address this issue, we identified the behavioral characteristics and neuronal codes for sequential and simultaneous number formats in crows. We find a format-dependent representation by distinct groups of selective neurons during the sensory encoding stage. However, an abstract and format-independent numerosity code emerges once the encoding phase is completed and numerosities needed to be memorized. These results suggest a successive two-stage code for categorically different number formats and help to reconcile conflicting findings observed in psychophysics and brain imaging.
人类的符号计数能力建立在一种原始的能力基础上，即大约估计物品数量或数值的能力。迄今为止，人们一直在争论在大脑中是否以抽象的方式表示以截然不同的格式呈现的数值，即作为时间序列与空间数组。为了解决这个问题，我们确定了乌鸦的顺序和同时数字格式的行为特征和神经元代码。我们在感觉编码阶段发现了不同选择性神经元群体的格式依赖性表示。然而，一旦完成编码阶段并需要记住数值，就会出现一个抽象的、与格式无关的数值代码。这些结果表明，对于截然不同的数字格式，存在一个连续的两阶段代码，有助于调和在心理物理学和脑成像中观察到的相互矛盾的发现。
