Kido Teruaki, Yotsumoto Yuko, Hayashi Masamichi J
Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan.
Nat Commun. 2025 Jan 6;16(1):419. doi: 10.1038/s41467-024-55599-8.
The ability to estimate numerical magnitude is essential for decision-making and is thought to underlie arithmetic skills. In humans, neural populations in the frontoparietal regions are tuned to represent numerosity. However, it remains unclear whether their response properties are fixed to a specific numerosity (i.e., absolute code) or dynamically scaled according to the range of numerosities relevant to the context (i.e., relative code). Here, using functional magnetic resonance imaging combined with multivariate pattern analysis, we uncover evidence that representations of relative numerosity coding emerge gradually as visual information processing advances in the frontoparietal regions. In contrast, the early sensory areas predominantly exhibit absolute coding. These findings indicate a hierarchical organization of relative numerosity representations that adapt their response properties according to the context. Our results highlight the existence of a context-dependent optimization mechanism in numerosity representation, enabling the efficient processing of infinite magnitude information with finite neural resources.
估计数值大小的能力对于决策至关重要，并且被认为是算术技能的基础。在人类中，额顶叶区域的神经群体被调整以表征数量。然而，它们的反应特性是固定于特定数量（即绝对编码）还是根据与上下文相关的数量范围动态缩放（即相对编码）仍不清楚。在这里，我们使用功能磁共振成像结合多变量模式分析，发现有证据表明，随着视觉信息在前额叶顶叶区域的处理推进，相对数量编码的表征逐渐出现。相比之下，早期感觉区域主要表现出绝对编码。这些发现表明存在一种相对数量表征的层次组织，其根据上下文调整反应特性。我们的结果突出了数量表征中存在一种依赖于上下文的优化机制，能够利用有限的神经资源高效处理无限的数量信息。
