In interval reproduction tasks, animals must remember the event starting the interval and anticipate the time of the planned response to terminate the interval. The interval reproduction task thus allows for studying both memory for the past and anticipation of the future. We analyzed previously published recordings from the rodent medial prefrontal cortex [J. Henke et al. , eLife 10 , e71612 (2021)] during an interval reproduction task and identified two cell groups by modeling their temporal receptive fields using hierarchical Bayesian models. The firing in the “past cells” group peaked at the start of the interval and relaxed exponentially back to baseline. The firing in the “future cells” group increased exponentially and peaked right before the planned action at the end of the interval. Contrary to the previous assumption that timing information in the brain has one or two time scales for a given interval, we found strong evidence for a continuous distribution of the exponential rate constants for both past and future cell populations. The real Laplace transformation of time predicts exponential firing with a continuous distribution of rate constants across the population. Therefore, the firing pattern of the past cells can be identified with the Laplace transform of time since the past event while the firing pattern of the future cells can be identified with the Laplace transform of time until the planned future event.

中文翻译：

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啮齿动物内侧前额叶皮层中的斜坡细胞通过真正的拉普拉斯变换编码过去和未来事件的时间


在间隔繁殖任务中，动物必须记住间隔开始的事件，并预测终止间隔的计划响应时间。因此，间隔再现任务可以研究过去的记忆和未来的预期。我们分析了先前发表的啮齿动物内侧前额叶皮层的记录[J.亨克等人。 ，eLife 10，e71612（2021）]在间隔复制任务期间，通过使用分层贝叶斯模型对它们的时间感受野进行建模来识别两个细胞组。 “过去的细胞”组的放电在间隔开始时达到顶峰，然后呈指数衰减回到基线。 “未来细胞”组的放电呈指数级增加，并在间隔结束时的计划行动之前达到峰值。与之前的假设相反，即大脑中的计时信息对于给定的时间间隔有一个或两个时间尺度，我们发现了强有力的证据表明过去和未来细胞群的指数速率常数连续分布。真正的时间拉普拉斯变换预测指数激发，速率常数在整个群体中连续分布。因此，过去细胞的放电模式可以通过自过去事件以来的时间拉普拉斯变换来识别，而未来细胞的放电模式可以通过计划的未来事件之前的时间拉普拉斯变换来识别。