Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, North Carolina, United States.
Elife. 2018 Nov 2;7:e38052. doi: 10.7554/eLife.38052.
Hippocampal oscillations arise from coordinated activity among distinct populations of neurons and are associated with cognitive functions. Much progress has been made toward identifying the contribution of specific neuronal populations in hippocampal oscillations, but less is known about the role of hippocampal area CA2, which is thought to support social memory. Furthermore, the little evidence on the role of CA2 in oscillations has yielded conflicting conclusions. Therefore, we sought to identify the contribution of CA2 to oscillations using a controlled experimental system. We used excitatory and inhibitory DREADDs to manipulate CA2 neuronal activity and studied resulting hippocampal-prefrontal cortical network oscillations. We found that modification of CA2 activity bidirectionally regulated hippocampal and prefrontal cortical low-gamma oscillations and inversely modulated hippocampal ripple oscillations in mice. These findings support a role for CA2 in low-gamma generation and ripple modulation within the hippocampus and underscore the importance of CA2 in extrahippocampal oscillations.
海马体振荡源于不同神经元群体之间的协调活动,与认知功能有关。在确定特定神经元群体在海马体振荡中的贡献方面已经取得了很大进展,但对于被认为支持社交记忆的海马体区域 CA2 的作用知之甚少。此外,关于 CA2 在振荡中作用的少量证据得出了相互矛盾的结论。因此,我们试图使用受控实验系统来确定 CA2 对振荡的贡献。我们使用兴奋性和抑制性 DREADDs 来操纵 CA2 神经元活动,并研究了由此产生的海马-前额叶皮质网络振荡。我们发现,CA2 活性的修饰双向调节海马体和前额叶皮质的低γ波振荡,并反向调节小鼠海马体的涟漪振荡。这些发现支持 CA2 在海马体内部的低γ波产生和涟漪调制中的作用,并强调了 CA2 在海马体外振荡中的重要性。