Department of Neurosurgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Center for Brains, Minds and Machines, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Cell Rep. 2023 Nov 28;42(11):113271. doi: 10.1016/j.celrep.2023.113271. Epub 2023 Oct 31.
Grid cells in the entorhinal cortex demonstrate spatially periodic firing, thought to provide a spatial map on behaviorally relevant length scales. Whether such periodicity exists for behaviorally relevant time scales in the human brain remains unclear. We investigate neuronal firing during a temporally continuous experience by presenting 14 neurosurgical patients with a video while recording neuronal activity from multiple brain regions. We report on neurons that modulate their activity in a periodic manner across different time scales-from seconds to many minutes, most prevalently in the entorhinal cortex. These neurons remap their dominant periodicity to shorter time scales during a subsequent recognition memory task. When the video is presented at two different speeds, a significant percentage of these temporally periodic cells (TPCs) maintain their time scales, suggesting a degree of invariance. The TPCs' temporal periodicity might complement the spatial periodicity of grid cells and together provide scalable spatiotemporal metrics for human experience.
网格细胞在海马旁回皮层表现出空间周期性放电，被认为提供了与行为相关的尺度上的空间图谱。在人类大脑中，这种周期性是否存在于与行为相关的时间尺度上仍不清楚。我们通过向 14 名神经外科患者展示视频，同时记录来自多个脑区的神经元活动，来研究在时间上连续的体验中神经元的放电情况。我们报告了一些神经元，它们在不同的时间尺度上以周期性的方式调节它们的活动——从秒到几分钟，最常见于海马旁回皮层。这些神经元在随后的识别记忆任务中，将其主导的周期性重新映射到更短的时间尺度上。当视频以两种不同的速度呈现时，相当一部分的这些时间周期性细胞（TPC）保持其时间尺度，这表明存在一定程度的不变性。TPC 的时间周期性可能补充了网格细胞的空间周期性，共同为人类体验提供了可扩展的时空度量。
