Redwood Center for Theoretical Neuroscience, Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States.
Department of Physics, University of California, Berkeley, Berkeley, United States.
Elife. 2019 Nov 18;8:e46351. doi: 10.7554/eLife.46351.
Grid cells fire in sequences that represent rapid trajectories in space. During locomotion, theta sequences encode sweeps in position starting slightly behind the animal and ending ahead of it. During quiescence and slow wave sleep, bouts of synchronized activity represent long trajectories called replays, which are well-established in place cells and have been recently reported in grid cells. Theta sequences and replay are hypothesized to facilitate many cognitive functions, but their underlying mechanisms are unknown. One mechanism proposed for grid cell formation is the continuous attractor network. We demonstrate that this established architecture naturally produces theta sequences and replay as distinct consequences of modulating external input. Driving inhibitory interneurons at the theta frequency causes attractor bumps to oscillate in speed and size, which gives rise to theta sequences and phase precession, respectively. Decreasing input drive to all neurons produces traveling wavefronts of activity that are decoded as replays.
网格细胞以代表空间中快速运动轨迹的序列方式放电。在运动过程中，θ 序列编码的位置扫掠从动物稍微落后的位置开始，结束于其前方。在静止和慢波睡眠期间，同步活动的爆发代表了被称为重放的长轨迹，这些在位置细胞中已经得到很好的证实，并且最近在网格细胞中也有报道。θ 序列和重放被假设为促进许多认知功能，但它们的潜在机制尚不清楚。网格细胞形成的一种机制是连续吸引子网络。我们证明，这种既定的架构自然会产生θ 序列和重放，作为调节外部输入的不同结果。以θ 频率驱动抑制性中间神经元会导致吸引子凸起以速度和大小的方式振荡，分别产生θ 序列和相位进动。减少对所有神经元的输入驱动会产生被解码为重放的活动的行波前。
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