Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain
Sensory and Working Memory Representations of Small and Large Numerosities in the Crow Endbrain
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DOI：
10.1523/jneurosci.1521-16.2016
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发表时间：
2016-11-23
影响因子：
5.3
通讯作者：
Nieder, Andreas
中科院分区：
文献类型：
--
作者：
Ditz, Helen M.;Nieder, Andreas
鸟类尾侧核(NCL)是一种独立于哺乳动物新皮质的终脑结构，其神经元处理视觉数字。为了阐明鸟类这个在解剖学上截然不同的终脑区域的数字密码，我们分析了神经元对广泛数字范围的反应。我们记录了执行延迟匹配到样本任务的乌鸦的NCL的单个神经元活动，并以视觉数字为判别符。20%的随机选择的神经元的反应被从1到30个项目的数字显著调制。数字选择神经元显示钟形调谐曲线，其中一个数字是首选数字，与物品的物理外观无关。由此得到的标签线码表现出对数压缩，其幅度服从韦伯-费克纳定律。不仅在刺激呈现阶段，而且在延迟阶段，也发现了类似比例的选择性神经元，这表明NCL在数字工作记忆中起主导作用。在工作记忆中的感觉编码和数字记忆过程中，NCL活动都能预测乌鸦的数字辨别能力。这些神经元数据揭示了脊椎动物之间在数字编码上惊人的相似之处，尽管它们的终脑结构是一致进化的，在解剖学上截然不同。
Neurons in the avian nidopallium caudolaterale (NCL), an endbrain structure that originated independently from the mammalian neocortex, process visual numerosities. To clarify the code for number in this anatomically distinct endbrain area in birds, neuronal responses to a broad range of numerosities were analyzed. We recorded single-neuron activity from the NCL of crows performing a delayed match-to-sample task with visual numerosities as discriminanda. The responses of > 20% of randomly selected neurons were modulated significantly by numerosities ranging from one to 30 items. Numerosity-selective neurons showed bell-shaped tuning curves with one of the presented numerosities as preferred numerosity regardless of the physical appearance of the items. The resulting labeled-line code exhibited logarithmic compression obeying the Weber-Fechner law for magnitudes. Comparable proportions of selective neurons were found, not only during stimulus presentation, but also in the delay phase, indicating a dominant role of the NCL in numerical working memory. Both during sensory encoding and memorization of numerosities in working memory, NCL activity predicted the crows' number discrimination performance. These neuronal data reveal striking similarities across vertebrate taxa in their code for number despite convergently evolved and anatomically distinct endbrain structures.