Zhang Wei, Guo Lei, Liu Dongzhao
School of Information Engineering, Tianjin University of Commerce, No. 409 Guangrong Rd, Beichen District, Tianjin, 300134, China.
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, School of Electrical Engineering, Hebei University of Technology, Tianjin, 300130, China.
Brain Struct Funct. 2022 Jun;227(5):1735-1755. doi: 10.1007/s00429-022-02469-y. Epub 2022 Feb 20.
Spatial working memory (SWM) refers to a short-term system for temporary manipulation of spatial information and requires the cooperation of multiple brain regions. Despite evidence that the hippocampus (HPC) and prefrontal cortex (PFC) are involved in SWM, how the PFC and HPC interact during SWM remains puzzling. In this study, local field potentials (LFPs) were recorded simultaneously from rat ventral HPC and medial PFC during SWM tasks firstly. A cross-frequency coupling algorithm was used to test for functional connectivity in the PFC and HPC. Granger causality (GC) algorithm was used to test for effective connectivity in the PFC and HPC. Finally, concurrent interactions across two brain regions were analyzed based on functional connectivity and effective connectivity. Experimental results show that the LFPs power in the PFC and HPC decreased during the learning period and peaked before the rats' behavioral selection during SWM. Moreover, the LFPs power mainly distributed in theta and gamma that are related to SWM. In relation to the functional connectivity, the effect of activity transmission during SWM in the PFC and HPC is the same; the phase-amplitude coupling (PAC) between gamma in the PFC and theta in the HPC is correlated with the formation of SWM and supports concurrent interactions between the PFC and HPC. In relation to the effective connectivity, the directed activity transmission in the HPC is greater than that in the PFC during SWM, indicating flow of activity from the HPC to the PFC.
空间工作记忆（SWM）是指一种用于临时处理空间信息的短期系统，需要多个脑区的协同作用。尽管有证据表明海马体（HPC）和前额叶皮质（PFC）参与了SWM，但在SWM过程中PFC和HPC如何相互作用仍不清楚。在本研究中，首先在大鼠进行SWM任务期间，同时记录其腹侧HPC和内侧PFC的局部场电位（LFP）。使用交叉频率耦合算法来测试PFC和HPC中的功能连接性。使用格兰杰因果关系（GC）算法来测试PFC和HPC中的有效连接性。最后，基于功能连接性和有效连接性分析两个脑区之间的并发相互作用。实验结果表明，在学习期间，PFC和HPC中的LFP功率下降，并在大鼠进行SWM的行为选择之前达到峰值。此外，LFP功率主要分布在与SWM相关的theta和gamma频段。关于功能连接性，在SWM期间PFC和HPC中活动传递的效果是相同的；PFC中的gamma与HPC中的theta之间的相位-幅度耦合（PAC）与SWM的形成相关，并支持PFC和HPC之间的并发相互作用。关于有效连接性，在SWM期间HPC中的定向活动传递大于PFC中的定向活动传递，表明活动从HPC流向PFC。
