CA2 neuronal activity controls hippocampal low gamma and ripple oscillations
- National Institute of Environmental Health Science, National Institutes of Health, United States
Abstract
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.
Data availability
The mouse line used in this study will be made freely available through Jackson Laboratories. The data used to generate bar graphs in figures are listed in Supplementary File 1.
Article and author information
Author details
Georgia M Alexander
Funding
National Institute of Environmental Health Sciences (ES100221)
- Serena M Dudek
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Laura Colgin, The University of Texas at Austin, Center for Learning and Memory, United States
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (ACUC) protocol (#2009-0023) of the NIEHS (A4149-1). All surgery was performed under ketamine and xylazine anesthesia, and every effort was made to minimize suffering.
Version history
- Received: May 2, 2018
- Accepted: November 2, 2018
- Accepted Manuscript published: November 2, 2018 (version 1)
- Version of Record published: November 23, 2018 (version 2)
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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CA2 neuronal activity controls hippocampal low gamma and ripple oscillations
eLife 7:e38052.
https://doi.org/10.7554/eLife.38052
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