Department of Epileptology, University of Bonn Medical Center, Venusberg-Campus 1, 53127 Bonn, Germany; Animal Physiology, Institute of Neurobiology, University of Tübingen, 72076 Tübingen, Germany.
Department of Epileptology, University of Bonn Medical Center, Venusberg-Campus 1, 53127 Bonn, Germany.
Curr Biol. 2024 Oct 21;34(20):4794-4802.e3. doi: 10.1016/j.cub.2024.08.041. Epub 2024 Sep 24.
The number zero holds a special status among numbers, indispensable for developing a comprehensive number theory. Despite its importance in mathematics, the neuronal foundation of zero in the human brain is unknown. We conducted single-neuron recordings in neurosurgical patients while they made judgments involving nonsymbolic number representations (dot numerosity), including the empty set, and symbolic numbers (Arabic numerals), including numeral zero. Neurons showed responsiveness to either the empty set or numeral zero, but not both. Neuronal activity to zero in both nonsymbolic and symbolic formats exhibited a numerical distance effect, indicating that zero representations are integrated together with countable numerosities and positive integers at the low end of the number line. A boundary in neuronal coding existed between the nonsymbolic empty set and small numerosities, correlating with the relative difficulty in discriminating numerosity zero behaviorally. Conversely, no such boundary was found for symbolic zero activity, suggesting that symbolic representations integrate zero with other numerals along the number line, reconciling its outlier role. The status of zero as a special nonsymbolic numerical quantity is reflected in the activity of neurons in the human brain, which seems to serve as a scaffold for more advanced representations of zero as a symbolic number.
零在数字中具有特殊地位，对于发展全面的数论不可或缺。尽管零在数学中很重要，但人类大脑中零的神经元基础尚不清楚。我们在神经外科患者进行了单神经元记录，当他们进行涉及非符号数字表示（点数量）的判断时，包括空集和符号数字（阿拉伯数字），包括数字零。神经元对空集或数字零都有反应，但不是两者都有。零在非符号和符号格式中的神经元活动都表现出数值距离效应，表明零的表示与可数数量和正数在线性数字的低端一起被整合在一起。在非符号空集和小数量之间存在神经元编码的边界，与行为上区分数量零的相对难度相关。相反，对于符号零的活动没有发现这样的边界，这表明符号表示沿着数线将零与其他数字整合在一起，从而协调了它的异常作用。零作为一种特殊的非符号数量的地位反映在人类大脑中神经元的活动中，这似乎为零作为符号数字的更高级表示提供了一个基础。
