Department of Psychiatry & Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, 94304, USA.
Department of Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, CA, 94304, USA.
Nat Commun. 2023 Jun 29;14(1):3843. doi: 10.1038/s41467-023-39548-5.
Number sense, the ability to decipher quantity, forms the foundation for mathematical cognition. How number sense emerges with learning is, however, not known. Here we use a biologically-inspired neural architecture comprising cortical layers V1, V2, V3, and intraparietal sulcus (IPS) to investigate how neural representations change with numerosity training. Learning dramatically reorganized neuronal tuning properties at both the single unit and population levels, resulting in the emergence of sharply-tuned representations of numerosity in the IPS layer. Ablation analysis revealed that spontaneous number neurons observed prior to learning were not critical to formation of number representations post-learning. Crucially, multidimensional scaling of population responses revealed the emergence of absolute and relative magnitude representations of quantity, including mid-point anchoring. These learnt representations may underlie changes from logarithmic to cyclic and linear mental number lines that are characteristic of number sense development in humans. Our findings elucidate mechanisms by which learning builds novel representations supporting number sense.
数感，即解读数量的能力，是数学认知的基础。然而，学习过程中数感是如何产生的还不得而知。在这里，我们使用一种受生物启发的神经架构，由皮质层 V1、V2、V3 和顶内沟（IPS）组成，来研究神经表示如何随数量训练而变化。学习在单个单元和群体水平上都极大地改变了神经元的调谐特性，导致 IPS 层中数量的调谐表示的出现。消融分析表明，学习前观察到的自发数字神经元对于学习后数量表示的形成并不是关键的。至关重要的是，群体反应的多维标度揭示了数量的绝对和相对大小表示的出现，包括中点锚定。这些习得的表示可能是对数到循环和线性心理数字线变化的基础，对数到循环和线性心理数字线是人类数感发展的特征。我们的研究结果阐明了学习构建支持数感的新表示的机制。
