Episodic memory is believed to be intimately related to our experience of the passage of time. Indeed, neurons in the hippocampus and other brain regions critical to episodic memory code for the passage of time at a range of timescales. The origin of this temporal signal, however, remains unclear. Here, we examined temporal responses in the entorhinal cortex of macaque monkeys as they viewed complex images. Many neurons in the entorhinal cortex were responsive to image onset, showing large deviations from baseline firing shortly after image onset but relaxing back to baseline at different rates. This range of relaxation rates allowed for the time since image onset to be decoded on the scale of seconds. Further, these neurons carried information about image content, suggesting that neurons in the entorhinal cortex carry information about not only when an event took place but also, the identity of that event. Taken together, these findings suggest that the primate entorhinal cortex uses a spectrum of time constants to construct a temporal record of the past in support of episodic memory.

情节记忆被认为与我们经历时间的流逝密切相关。的确，对情景记忆至关重要的海马和其他大脑区域中的神经元在一定时间范围内编码时间的流逝。然而，该时间信号的起源仍不清楚。在这里，我们检查了猕猴观察复杂图像时内嗅皮层的时间响应。内嗅皮层中的许多神经元对图像发作有反应，显示出与图像发作后不久的基线放电有很大的差异，但以不同的速率放松回到基线。此松弛率范围允许自图像出现以来的时间以秒为单位进行解码。此外，这些神经元携带有关图像内容的信息，这表明内嗅皮层中的神经元不仅携带有关事件发生的时间的信息，还携带有关该事件的身份的信息。综上所述，这些发现表明灵长类动物内嗅皮层使用一系列时间常数来构建过去的时间记录，以支持情节记忆。