Large- and multi-scale networks in the rodent brain during novelty exploration

Neural activity is coordinated across multiple spatial and temporal scales, and these patterns of coordination are implicated in both healthy and impaired cognitive operations. However, empirical cross-scale investigations are relatively infrequent, due to limited data availability and to the difficulty of analyzing rich multivariate datasets. Here we applied frequency-resolved multivariate source-separation analyses to characterize a large-scale dataset comprising spiking and local field potential activity recorded simultaneously in three brain regions (prefrontal cortex, parietal cortex, hippocampus) in freely-moving mice. We identified a constellation of multidimensional, inter-regional networks across a range of frequencies (2-200 Hz). These networks were reproducible within animals across different recording sessions, but varied across different animals, suggesting individual variability in network architecture. The theta band (~4-10 Hz) networks had several prominent features, including roughly equal contribution from all regions and strong inter-network synchronization. Overall, these findings demonstrate a multidimensional landscape of large-scale functional activations of cortical networks operating across multiple spatial, spectral, and temporal scales during open-field exploration.

神经活动于多个空间与时间尺度间协同运转，此类协同模式既与健康认知功能密切相关，也参与认知功能受损的病理过程。然而，受限于数据可获取性不足与高维多元数据集的分析难度，此类实证性跨尺度研究相对匮乏。本研究采用频域解析多元源分离分析方法，对一项大型数据集开展特征表征工作：该数据集采集了自由活动小鼠三个脑区——前额叶皮层（prefrontal cortex）、顶叶皮层（parietal cortex）与海马体（hippocampus）——的同时记录信号，包括神经元尖峰放电与局部场电位（Local Field Potential, LFP）。我们在2~200 Hz的宽频范围内，识别出一组多维度脑区间协同网络集群。此类网络在同一动物的不同记录批次中具备可重复性，但在不同个体间存在显著差异，提示网络架构存在个体差异性。θ频段（~4~10 Hz）网络具备多项显著特征，包括各脑区贡献大致均等，以及网络间存在强同步性。综上，本研究结果揭示了小鼠在旷场探索过程中，跨多空间、频谱与时间尺度运作的皮层网络大规模功能激活的多维度图景。