Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany.
Bernstein Center for Computational Neuroscience Munich, Munich, Germany.
Elife. 2021 Dec 23;10:e71612. doi: 10.7554/eLife.71612.
As we interact with the external world, we judge magnitudes from sensory information. The estimation of magnitudes has been characterized in primates, yet it is largely unexplored in nonprimate species. Here, we use time interval reproduction to study rodent behavior and its neural correlates in the context of magnitude estimation. We show that gerbils display primate-like magnitude estimation characteristics in time reproduction. Most prominently their behavioral responses show a systematic overestimation of small stimuli and an underestimation of large stimuli, often referred to as regression effect. We investigated the underlying neural mechanisms by recording from medial prefrontal cortex and show that the majority of neurons respond either during the measurement or the reproduction of a time interval. Cells that are active during both phases display distinct response patterns. We categorize the neural responses into multiple types and demonstrate that only populations with mixed responses can encode the bias of the regression effect. These results help unveil the organizing neural principles of time reproduction and perhaps magnitude estimation in general.
当我们与外部世界互动时，我们会根据感官信息来判断大小。大小的估计在灵长类动物中已经得到了描述，但在非灵长类动物中还很大程度上没有被探索。在这里，我们使用时间间隔再现来研究啮齿动物在大小估计背景下的行为及其神经相关性。我们表明，沙鼠在时间再现中表现出类似灵长类的大小估计特征。最突出的是，它们的行为反应表现出对小刺激的系统高估和对大刺激的低估，通常称为回归效应。我们通过记录内侧前额叶皮层的神经元活动来研究潜在的神经机制，并表明大多数神经元在时间间隔的测量或再现期间都会产生反应。在两个阶段都活跃的细胞显示出不同的反应模式。我们将神经反应分为多种类型，并证明只有具有混合反应的群体才能对回归效应的偏差进行编码。这些结果有助于揭示时间再现的组织神经原则，也许还有一般的大小估计。
